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Reflection During a Day of Skeletal Processing

8 Feb

I have a day off from my normal job and I find myself carefully wet sieving the cremated remains of a suspected Romano-British individual in the processing room at the local unit, but I’m not alone here.  Instead I’m surrounded by recently excavated Anglo-Saxon remains drying slowly on paper towels, organised in numerous plastic trays on various shelves to my side and up above me.  In each tray there is a plastic zip bag, the site code and context number inked on for identification purpose and later site reconstruction.  By taking the right femoral head and neck (upper thigh) as an identifier of the minimum number of individuals (MNI), I count at least six individuals represented in the new assemblage, although there are a few trays I cannot quite see and as I am not here to look at them I do not uncover them.  A quick look at the morphology (size and shape) of the individual skeletal elements is enough to see that, demographically speaking, adults and non-adults are represented in the assemblage.

Browsing the mandibles (lower jaw) that are present I can see a few without the 3rd molar fully erupted, one or two lying in crypts waiting to reach up for the shaft of light from the outside world that would never come.  Another mandible has the majority of the teeth present, including the 1st, 2nd and 3rd molars in each half, but displays severe enamel wear of the crowns of the teeth (the occlusal, or biting surface), indicative of a rough diet and probable middle to advanced adult age.  The fact that most of the teeth are present suggest that the individual wasn’t too old though, as tooth loss is strongly correlated to increasing age for humans.

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A day in the archive stores analysing non-adult skeletal remains from an archaeological site. Photograph by the author use a Pentax ME Super camera and Lomography Lady Grey film, if used elsewhere please inform the author and credit as appropriate.

I turn my attention back to the cremated remains.  These are something of a mystery having looked at the context sheets dating from the excavation itself.  There is evidence for cremated non-human remains, likely to be bovine (cow to you and me) as there are a few distinctive teeth included in the bags in an associated context found near the cremated remains that I’m now processing, which itself has been bulk sampled at 100%.  A proper look through the sieved cremated material, which has been processed in accordance with the British Association of Biological Anthropology and Osteoarchaeology guidelines, will have to wait though as they need to dry over the next few days, ideally for another few days after too.  Once dry I can go through each fraction sieved (10mm, 6mm, 2mm) and sort as human and non-human, before identifying specific osteological features and assigning the fragments to either skull, limb, or trunk sections of the skeleton.

As I think about this I remember that I must complete this human osteology report soon.

For many people the thought of touching or analyzing human remains is too much, that in many minds remains are parceled off to the medical realm or are hurried to the cemetery to be removed out of sight.  In reality though we are often surrounded by human remains, though we may not always know it and may not always want to know it.  In archaeology the skeletal remains of humans are often the only direct biological matter to survive of individuals and past populations.  They can encode and preserve a lot of information on biological matters and past cultural practices.  This has been steadily recognized within the past century as osteological methodologies are refined for accuracy and new technology is applied in novel approaches to the remains unearthed.  One of the prime concerns for any bioarchaeologist or human osteologist is that ethical codes and guidelines are adhered to, with the relevant legal permits acquired as appropriate.  As I glance upon the presumed Anglo-Saxon remains I remember that these too were unexpected finds by the construction workers, I briefly wonder how they felt and what they thought on seeing them for the first time.

Anyhow, back to processing the cremation and to thinking about writing the report.

It is pretty interesting as although I’ve part-processed cremations within urns before, with careful micro-excavation spit by spit, I’ve never fully processed a cremation to completion.  Whether these cremated remains represent human skeletal material, as the field notes state, remains a different matter though and it is one I am eager to solve…

Further Learning

  • The British Association of Biological Anthropology and Osteoarchaeology (BABAO) promotes the study of understanding the ‘physical development of the human species from the past to the present’.  As an association they provide research grants for projects in which all members of BABAO are eligible, as well as offering prizes for presentations and posters in their annual conference, which is held in the United Kingdom.  I fully recommend attending and taking part if you are associated with any relevant field.
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Skeletal Series: The Basic Human Osteology Glossary

19 Dec

Introducing the Human Osteology Glossary

It is important for the budding human osteology student that they understand and correctly apply the basic terms used in the discipline to help identify and describe the skeletal anatomy under study.  Since human osteologists study the skeletal remains of anatomically modern humans (Homo sapiens) the terminology used, specifically the anatomical terminology, has to be precise and correct as befitting the medical use of such terms.

Human osteology remains the foundation on which the disciplines of forensic anthropology and bioarchaeology are built upon, although it is noted that the disciplines can be misleading across international divides.  For example, in the United Kingdom bioarchaeology is still used to refer to the study of both human and non-human skeleton remains from archaeological sites, whilst bioarchaeology in the United States normally refers to human remains only.  It should also be noted here that the other related disciplines, such as palaeoanthropology and biological anthropology, study not just the modern human skeleton but also the skeletal and fossilized remains of extant (genera such as Pan, Pongo and Gorilla) and extinct hominins.  Nevertheless the terminology remains the same when describing the skeletal anatomy of both human and non-human individuals.

Glossary Arrangement

This short glossary is intended to provide a basic introduction to the terminology used in the disciplines that utilizes human osteology as a core focus for the research undertaken.  The terminology documented here also includes a brief description of the word and, where possible, an example of its use.  Primarily the glossary acts as a reference post in order to be used in conjunction with the Skeletal Series posts on this site, which help outline and introduce each skeletal element of the human body section by section and as appropriate.  However please note that the glossary is also arranged in a manner in which it befits the student who needs to quickly scan the list in order to find a specific and relevant word.

Therefore the glossary is arranged in a thematic presentation as follows:

1. Discipline Definitions
2. The Human Body:
– a) Macro
– b) Micro
– c) Growth
– d) Disease and Trauma
3. Anatomical Foundations:
– a) Anatomical Planes of Reference
– b) Directional Terminology
– c) Movement Terminology
4. Postmortem Skeletal Change
– a) Postmortem Skeletal Change

The glossary ends with an introduction to the terminology used to describe the postmortem aspects of body deposition.  This is because it is an important aspect and consideration of any skeletal analysis undertaken.  The terminology used in this section leads away from the strictly anatomical terminology of the sections above it and introduces some terms that are used in archaeology and associated disciplines.

Reference Note

Please note that the bibliography provided indicates a number of important texts from which this glossary was compiled.  The key text books highlighted also introduce the study of the human skeleton, from a number of different perspectives, including the gross anatomical, bioarchaeological and human evolutionary perspectives.  Find a copy of the books at your library or order a copy and become engrossed in the beauty of the bones and the evidence of life histories that they can hold.

The Glossary:

1) – Discipline Definitions

Bioanthropology:  A scientific discipline concerned with the biological and behavioral aspects of human beings, their related non-human primates, such as gorillas and chimpanzees, and their extinct hominin ancestors.  (Related Physical Anthropology).

Bioarchaeology:  The study of human and non-human skeletal remains from archaeological sites.  In the United States of America this term is used solely for the study of human skeletal remains from archaeological sites.

Forensic Anthropology:  An applied anthropological approach dealing with human remains in legal contexts.  Forensic anthropologists often work with coroners and others, such as disaster victim identification teams, in analysing and identifying human remains (both soft and hard tissues) from a variety of contexts including but not limited ID’ing remains from natural disasters, police contexts, war zones, genocides, human rights violations, etc.

Human Osteology:  The study of human skeletal material.  Focuses on the scientific interpretation of skeletal remains from archaeological sites, including the study of the skeletal anatomy, bone physiology, and the growth and development of the skeleton itself.   

Palaeoanthropology:  The interdisciplinary study of earlier hominins.  This includes the study of their chronology, physical structure and skeletal anatomy, archaeological remains, geographic spans, etc. (Jurmain et al. 2011).

Physical Anthropology:  Concerned with the biological skeletal remains of both humans and extant and extinct hominins, anatomy, and evidence of behaviour.  The discipline is often considered congruent with the term bioanthropology, or biological anthropology.  (Related Bioanthropology).

2) a. – The Human Body: Macro

Appendicular Skeleton:  The skeletal bones of the limbs.  Includes the shoulder and pelvic girdles, however it does not include the sacrum.  Skeleton SK423 largely consisted of the non-fragmented disarticulated appendicular elements.

Axial Skeleton:  The skeletal elements of the trunk of the body.  Includes the ribs, vertebrae and sternum.  The body of SK424 was particularly fragmented in-situ, with little sign of excavation or post-excavation damage evidenced on the axial skeleton suggesting fragmentation post-burial.

Cortical (Compact) Bone:  The solid and dense bone found in the bone shafts and on the external surfaces of bone itself.  The cortical bone of the mid-shaft of the right humerus of the tennis player displayed increased thickening.  This is, in this individuals case whose physical history is known, due to the predominance of the right arm during intense and long-term use in physical exercise (see Wolff’s Law). 

Dentin (Dentine):  Calcified but slightly resilient dental connective tissue.  In human growth primary dentin appears during growth whereas secondary dentin forms after the root formation of the tooth is complete (White & Folkens 2005: 421).

Diaphysis:  The shaft portion of a long bone.  The diaphysis of the femur is one of the longest shafts found in the human skeleton, as the femur is the longest bone.

Dry Bone:  Refers to archaeological bone where no soft, or wet, tissue survives, hence the bone is dry.  It should be noted that, when subject to x-rays for investigation, archaeological dry bone radiological images are improved due to a lack of soft tissues obscuring the bone condition.

Elements (Skeletal):  Used to refer to each individual bone.  The human adult body has, on average, 206 individual skeletal elements.

Enamel:  Enamel is an extremely hard brittle material which covers the crown of a tooth.

Endosteum:  A largely cellular membrane that lines the inner surface of bones which is ill-defined (White & Folkens 2005: 421).

Epiphysis:  The epiphysis refers to the often proximal and distal ‘caps’ of long bones that develop from a secondary ossification centre.  The epiphysis of the long bones can, when used in conjunction with other skeletal markers of aging, particularly dentition, provide a highly accurate  age-at-death in non-adult human skeletal remains.

Medullary Cavity:  The cavity found inside the shaft of a long bone.  The medullary cavity of the femur is the site of the longest medullary cavity found in the human body.  The medullary cavity is the location where red and yellow bone marrow is stored and where the red and white blood cells are produced. 

Metaphyses:  The metaphyses refer to the expanded and flared ends of the shaft (or diaphysis) of long bones.  Both the femoral and humeral diaphyses display flared distal metaphyses which are indicative of their anatomical positioning.

Morphology:  The form and structure of an object.  The morphology of the femora is dictated by a variety of factors, not least the size, age, sex and weight of the individual.

Musculoskeletal System:  The musculoskeletal system provides the bony framework of the body in which the muscles attach onto and are able to leverage bones to induce movement.  The musculoskeletal system is responsible for a number of core bodily functions, including blood production and nourishment, alongside providing a stable and safe environment for vital organs.

Osteology:  The scientific study of bone.  Bones form the basis of the skeletal system of vertebrate animals, including humans.  In the United States of America bioarchaeology refers to the study of human bones within an archaeological context.

Periosteum:  The thin dense vascular connective tissue that covers the outer surfaces of bone during life, except on areas of articulation.  The periosteum tissue plays an important part in the maintenance of healthy bone, helping to also provide the body with blood via the bone marrow and associated vessels.  The periosteum provides an important area of osteogensis following a bone fracture.

Postcranial Skeleton:  All bones but the mandible and cranium.  The postcranial skeleton of SK543 was exceptionally well-preserved within the grave context but due to grave cutting the cranium and mandible were completely disturbed and not present within the context recorded.

Trabecular (Spongy) Bone:  Refers to the honeycomb like structure of bone found within the cavity of bones themselves.

2) b. – The Human Body: Micro

Cartilage:  Cartilage is a flexible connective tissue which consists of cells embedded in a matrix.  In the human skeletal system cartilage is found between joints, such as the knee and in forms such as the intervertebral disk in the spine and in the ribcage.  There are three types of cartilage: hyaline, fibrocartilage and elastic cartilage in the human skeletal system, although 28 different types of cartilage have now been identified in the human body as a whole (Gosling et al. 2008:9).

Collagen:  Collagen is a fibrous structural tissue in the skeleton which constitutes up to 90% of bone’s organic content (White & Folkens 2005: 42).

Haversian Canal (Secondary Osteons):  Microscopic canals found in compact, or cortical, bone that contain blood, nerve and lymph vessels, alongside marrow.

Hydroxyapatite:  A dense, inorganic, mineral matrix which helps form the second component of bone.  Together with collagen hydroxyapatite gives bone the unique ability to withstand and respond to physical stresses.

Lamellar (Mature) Bone:  Bone in which the ‘microscopic structure is characterized by collagen fibres arranged in layers or sheets around Haversian canals’ (White & Folkens 2005: 423).  Lamellar bone is mechanically strong.  Related woven (immature) bone.

Osteoblast:  Osteoblasts are the ‘bone-forming cells which are responsible for synthesizing and depositing bone material’ (White & Folkens 2005: 424).

Osteoclast:  Osteoclasts are the cells responsible for the resorption of bone tissue.

Osteocyte:  Osteocytes are the living bone cell which is developed from an osteoblast (White & Folkens 2005: 424).

Osteon:  The osteon is a Haversian system, ‘a structural unit of compact bone composed of a central vascular (Haversian) canal and the concentric lamellae surrounding it; a Primary Osteon is composed of a vascular canal without a cement line, whereas the cement line and lamellar bone organized around the central canal characterize a Secondary Osteon‘ (White & Folkens 2005: 424).

Remodeling:  Remodeling is the cyclical process of bone resorption and bone deposition at one site.  The human skeleton continually remodels itself throughout life, and after full growth has been achieved towards the end of puberty.  Further to this bone is a tissue that responds to physical stress and remodels as appropriate. 

Woven (Immature) Bone:  characterized by the haphazard organisation of collagen fibres.  Primarily laid down following a fracture and later replaced by lamellar bone.  Woven bone is mechanically weak.  Related lamellar (mature) bone.

2) c. – The Human Body: Growth

Appositional Growth:  The process by which old bone that lines the medullary cavity is reabsorbed and new bone tissue is grown beneath the periosteum, which increases the bone diameter.

Endochondral Ossification:  One of two main processes of bone development in which cartilage precursors (called cartilage models) are gradually replaced by bone tissue (White & Folkens 2005: 421).

Epiphyseal (Growth) Plate:  The hyaline cartilage plate found at the metaphyses of the long bones during growth of the individual (i.e. non-adults), where bone growth is focused until full growth cycle has been completed.

Idiosyncratic:  Referring to the individual.  The normal morphology of the human skeleton, and its individual elements, is influenced by three main factors of variation: biological sex (sexual dimorphism), ontogenetic (age), and idiosyncratic (individual) factors.

Intramembranous Ossification:  One of two main processes of ‘bone development in which bones ossify by apposition on tissue within an embryonic connective tissue membrane’ (White & Folkens 2005: 422).

Ontogeny:  The growth, or development, of an individual.  Ontogeny can be a major factor in the morphological presentation of the human skeleton.

Osteogenesis:  The formation and development of bone.  Embryologically the development of bone ossification occurs during two main processes: intramembranous and endochondral ossification.

Wolff’s Law:  Theory developed by German anatomist and surgeon Julius Wolff (1836-1902) which stated that human and non-human bone responded to the loads, or stresses, under to which it is placed and remodels appropriately within a healthy individual.

Sexual Dimorphism:  The differences between males and females.  The human skeleton has, compared to some animal species, discrete differences in sexual dimorphism; however there are distinct functional differences in the morphology of certain elements which can be used to determine biological sex of the individual post-puberty.

2) d. – The Human Body: Disease and Trauma

Atrophy:  The wastage of an organ or body tissue due to non-use.  Atrophy can be an outcome of disease processes in which the nerves are damaged, leading to the extended, or permanent, non-use of a limb which can lead to muscle wastage and bone resorption.

Blastic Lesion: Expansive bone lesion in which bone is abnormally expanded upon as part of part of a disease process.  The opposite of lytic lesion.

Calculus: Tartar; a deposit of calcified dental plaque on the surface of teeth.  The calculus found on the teeth of the archaeological skeleton can contain a wealth of information on the diet and extramasticatory activities of the individual.

Callus:  The hard tissue which is formed in the osteogenic (bone cell producing) layer of the periosteum as a fracture repair tissue.  This tissue is normally replaced by woven bone, which is in turn replaced by lamellar (or mature) bone as the bone continues to remodel during the healing process.

Caries:  Caries are ‘a disease characterized by the ‘progressive decalcification of enamel or dentine; the hole or cavity left by such decay’ (White & Folkens 2005: 420).  The extensive caries present on the 2nd right mandibular molar of Sk344 nearly obliterates the occlusal (chewing) surface of the tooth.

Compound Fracture:  A fracture in which the broken ends of the bone perforate the skin.  A compound fracture can be more damaging psychologically to the individual, due to the sight of the fracture itself and soft tissue damage to the skin and muscle.  Compound fractures also lead to an increased risk of fat embolism (or clots) entering the circulatory system via marrow leakage, which can be potentially fatal.

Dysplasia:  The abnormal development of bone tissue.  The bone lesions of fibrous dysplasia display as opaque and translucent patches compared to normal healthy bone on X-ray radiographic images.

Eburnation: Presents as polished bone on surface joints where subchondral bone has been exposed and worn.  Osteoarthritis often presents at the hip and knee joints where eburnation is present on the proximal femoral head and distal femoral condyle surfaces, alongside the adjacent tibia and iliac joint surfaces.

Hyperostosis:  An abnormal growth of the bone tissue.  Paget’s disease of bone is partly characterized by the hyperostosis of the cranial plates, with particularly dense parietal and frontal bones.

Hyperplasia:  An excessive growth of bone, or other, tissues.

Hypertrothy:  An increase in the volume of a tissue or organ.

Hypoplasia:  An insufficient growth of bone or other tissue.  Harris lines are dense transverse lines found in the shafts of long bones, which are indicative of arrested growth periods, as non-specific stress events, in the life of the individual.  Harris lines can often only be identified via X-ray radiography or through visual inspection of internal bone structure.

Lytic Lesion:  Destructive bone lesion as part of a disease process.  The opposite of a blastic lesion.  Syphilitic lytic bone lesions often pit and scar the frontal, parietal and associated facial bones of the skull.

Osteoarthritis:  Osteoarthritis is the most common form of arthritis, which is characterized by the destruction of the articular cartilage in a joint.  This often leads to eburnation on the bone surface.  Bony lipping and spur formation often also occur adjacent to the joint.  This is also commonly called Degenerative Joint Disease (DJD) (White & Folkens 2005: 424).

Osteophytes:  Typically small abnormal outgrowths of bone which are found at the articular surface of the bone as a feature of osteoarthritis.  Extensive osteophytic lipping was noted on the anterior portion of the vertebrae bodies of T2-L3 which, along with the evidence of eburnation, bony lipping and spurs presenting bilaterally on the femora and tibiae, present as evidence of osteoarthritis in SK469.

Pathognomonic:  A pathological feature that is characteristic for a particular disease as it is a marked intensification for a diagnostic sign or symptom.  A sequestrum (a piece of dead bone that has become separated from normal, or healthy, bone during necrosis) is normally considered a pathgonomic sign of osteomyelitis. 

Pathological Fracture:  A bone fracture that occurs due to the result of bones already being weakened by other pathological or metabolic conditions, such as osteoporosis (White & Folkens 2005: 424).

Palaeopathology:  The study of ancient disease and trauma processes in human skeletal (or mummified) remains from archaeological sites.  Includes the diagnosis of disease, where possible.  A palaeopathological analysis of the skeletal remains of individuals from the archaeological record is an important aspect of recording and contextualising health in the past.

Periodontitis:  Inflammation around the tissues of a tooth, which can involve the hard tissues of the mandibular and maxilla bone or the soft tissues themselves.  Extensive evidence of periodontitis on both the mandible and maxilla suggests a high level of chronic infection.

Periostitis: The inflammation of the periosteum which is caused by either trauma or infection, this can be either acute or chronic.  The anterior proximal third of the right tibia displayed extensive periostitis suggesting an a persistent, or long term, incidence of infection.

Radiograph:  Image produced on photographic film when exposed to x-rays passing through an object (White & Folkens 2005: 425).  The radiographic image of the femora produced evidence of Harris lines which were not visible on the visual inspection of the bones.

3) a. – Anatomical Planes of Reference

Anatomical Position (Standard):  This is defined as ‘standing with the feet together and pointing forward, looking forward, with none of the leg bones crossed from a viewer’s perspective and palms facing forward’ (White & Folkens 2005: 426).  The standard anatomical position is used when referring to the planes of reference, and for orientation and laying out of the skeletal remains of an individual for osteological examination, inventory, and/or analysis.

Coronal (frontal/Median):  The coronal plane is a vertical plane that divides the body into an equal forward and backward (or anterior and posterior) section.  The coronal plane is used along with the sagittal and transverse planes in order to describe the location of the body parts in relation to one another.

Frankfurt Horizontal:  A plane used to systematically view the skull which is defined by three osteometric points:  the right and left porion points (near the ear canal, or exterior auditory meatus) and left orbitale.

Oblique Plane:  A plane that is not parallel to the coronal, sagittal or transverse planes.  The fracture to the mid shaft of the left tibia and fibula was not a transverse or spiral break, it is an oblique fracture as evidenced by the angle of the break. 

Sagittal:  A vertical plane that divides the body into symmetrical right and left halves.

Transverse:  Situated or extending across a horizontal plane.  A transverse fracture was noted on the midshaft of the right femur.  The fracture was indicative of a great force having caused it, likely in a traumatic incident.

3) b. – Anatomical Directional Terminology

Superior:  Superior refers towards the head end of the human body, with the most superior point of the human body the parietal bone at the sagittal suture (White & Folkens 2005: 68).

Inferior:  Inferior refers towards the foot, or the heel, which is the calcaneus bone.  Generally this is towards the ground.  The tibia is inferior to the femur.

Anterior:  Towards the front of the body.  The sternum is anterior to the vertebral column.

Posterior:  Towards the back of the body.  The occipital bone is posterior to the frontal bone of the cranium.

Proximal:  Near the axial skeletonThe term is normally used for the limb bones, where for instance the proximal end of the femur is towards the os coxa.

Medial:  Towards the midline of the body.  The right side of the tongue is medial to the right side of the mandible.

Lateral:  The opposite of medial, away from the midline of the body.  In the standard anatomical position the left radius is lateral to the left ulna.

Distal:  furthest away from the axial skeleton; away from the body.  The distal aspect of the humerus articulates with the proximal head of the radius and the trochlear notch of the ulna.

Internal:  Inside.  The internal surface of the frontal bone has the frontal crest, which is located in the sagittal plane.

External: Outside.  The cranial vault is the external surface of the brain.

Endocranial:  The inner surface of the cranial vault.  The brain fills the endocranial cavity where it sits within a sack.

Ectocranial:  The outer surface of the cranial vault.  The frontal bosses (or eminences) are located on the ectocranial surface of the frontal bone.

Superficial:  Close to the surface of the body, i.e. towards the skin.  The bones of the cranium are superficial to the brain.

Deep:  Opposite of superficial, i.e. deep inside the body and far from the surface.  The lungs are deep to the ribs, but the heart is deep to the lungs.

Palmar:  Palm side of the hand.  The palm side of the hand is where the fingers bear fingerprints.

Plantar:  The plantar side of the foot is the sole.  The plantar side of the foot is in contact with the ground during normal ambulation.

Dorsal:  Either the top of the foot or the back of the hand.  The ‘dorsal surface often bears hair whilst the palmar or plantar surfaces do not’ (White & Folkens 2005: 69).

3) c. – Anatomical Movement Terminology

Abduction:  Abduction is a laterally directed movement in the coronal plane away from the sagittal, or median, plane.  It is the opposite of adduction.  Standing straight, with the palm of the left hand anterior, raise the left arm sideways until it is horizontal with the shoulder: this is the action of abducting the left arm.

Adduction:  Adduction is the medially directed movement in the coronal plane towards the sagittal, or median, plane.  It is the opposite of abductionStanding straight, with the palm of the right hand anterior, and the right arm raised sideways until it is horizontal with the shoulder, move the arm down towards the body.  This is adduction.

Circumduction:  Circumduction is a ‘circular movement created by the sequential combination of abduction, flexion, adduction, and extension’ (Schwartz 2007: 373).  The guitarist who performs the action of windmilling during playing is circumducting their plectrum holding limb.

Extension:  Extension is a movement in the sagittal plane around a transverse axis that separates two structures.  It is the opposite of flexionThe extension of the forearm involves movement at the elbow joint.

Flexion:  A bending movement in the saggital plane and around a transverse axis that draws two structures toward each other (Schwartz 2007: 374).  It is the opposite of extensionThe flexion of the forearm involves movement at the elbow joint.

Lateral Rotation:  The movement of a structure around its longitudinal axis which causes the anterior surface to face laterally.  It is the opposite of medial rotation.

Medial Rotation:  The movement of a structure around its longitudinal axis that causes the anterior surface to face medially.  It is the opposite of lateral rotation (Schwartz 2007: 376).

Opposition: The movement of the ‘thumb across the palm such that its “pad” contracts the “pad” of another digit; this movement involves abduction with flexion and medial rotation’ (Schwartz 2007: 377).

4) a. – Postmortem Skeletal Change

Antemortem:  Before the time of death.  The evidence for the active bone healing on both the distal radius and ulna diaphyses, with a clean fracture indicating use of a bladed instrumented, suggests that amputation of the right hand occurred antemortem. 

Bioturbation:  The reworking of soils and associated sediments by non-human agents, such as plants and animals.  Bioturbation can lead to the displacement of archaeological artefacts and structural features and displace deposited human skeletal bone.  Evidence of bioturbation in the cemetery was noted, as irregular tunnels were located across a number of different grave contexts suggesting the action of a burrowing or nesting mammal.  This led to the disarticulation of skeletal material within the grave contexts themselves which, on first investigation, may have led to an incorrect analysis of the sequence of events following the primary deposition of the body within the grave.

Commingled:  An assemblage of bone containing the remains of multiple individuals, which are often incomplete and heavily fragmented.  The commingled mass grave found at the Neolithic site of Talheim, in modern southern Germany, suggest that, along with the noted traumatic injuries prevalent on the individuals analysed, rapid and careless burial in a so-called ‘death pit’ took place by the individuals who carried out the massacre.  The site is a famous Linearbandkeramik (LBK) location which dates to around 5000 BC, or the Early European Neolithic.  Similar period mass burials include those at Herxheim, also in Germany, and Schletz-Asparn in nearby Austria.

Diagenesis:  The chemical, physical, and biological changes undergone by a bone through time.  This is a particularly important area of study as the conservation of bones must deal with bacteria and fungal infection of conserved bone if the skeletal material is to be preserved properly.  Analysis of the diagenesis of skeletal material can also inform the bioarchaeologist of the peri and postmortem burial conditions of the individual by comparing the environmental contexts that the bone had been introduced to.

Perimortem: At, or around, the time of death.  The decapitation of SK246 occurred perimortem as evidenced by the sharp bladed unhealed trauma to the associated body,  pedicles, lamina and spinal arches of the C3 and C4 vertebrae.

Postmortem: Refers to the period after the death of the individual.  It is likely that the body had been moved postmortem as indicated by position of the body in the bedroom and by the extensive markers on the skin, suggesting physical manipulation and accidental contusions.  Further to this the pooling of the blood within the first few hours postmortem was not indicative of where the body was located at the time of discovery.

Postmortem Modification:  Modifications, or alterations, that occur to the skeletal remains after the death of the individual.  No postmortem modification of the skeletal elements of SK543 was noted, however extensive evidence of bioturbation in the form of root action was noted on across the majority (> 80%) of the surface of the surviving skeletal elements recovered.

Taphonomy:  The study of processes that can affect the skeletal remains between the death of the individual and the curation, or analysis, of the individual.  There are a variety of natural and non-natural taphonomic processes that must be considered in the analysing of human skeletal material from archaeological, modern and forensic contexts.  This can include natural disturbances, such as bioturbation, or non-natural, such as purposeful secondary internment of the body or skeletal remains.

Note on the Terminology Used & Feedback

The terminology used above, and their definitions, are taken in part from the below sources.  Direct quotations are referenced to the source and page.  They, the sources in the bibliography, are a small handful of some of the exceptional books available which help to introduce the human skeletal system and the importance of being able to identify, study and analyse the bones in a scientific manner.  The human skeletal glossary present here is subject to revision, amendments and updates, so please do check back to see what has been included.  Finally, I heartily advise readers to leave a comment if revisions, or clarifications, are needed on any of the terms or definitions used in the glossary.

Bibliography & Further Reading

Gosling, J. A., Harris, P. F., Humpherson, J. R., Whitmore, I., Willan, P. L. T., Bentley, A. L., Davies, J. T. & Hargreaves, J. L. 2008. Human Anatomy: Colour Atlas and Texbook (5th Edition). London: Mosby Elsevier.

Jurmain, R., Kilgrore, L. & Trevathan, W. 2011. Essentials of Physical Anthropology. Belmont: Wadsworth.

Larsen, C. S. 1997. Bioarchaeology: Interpreting Behaviour from the Human Skeleton. Cambridge: Cambridge University Press.

Lewis, M. E. 2007. The Bioarchaeology of Children: Perspectives from Biological and Forensic Anthropology. Cambridge: Cambridge University Press.

Roberts, C. & Manchester, K. 2010. The Archaeology of Disease (3rd Edition). Stroud: The History Press.

Schwartz, J. H. 2007. Skeleton Keys: An Introduction Human Skeletal Morphology, Development, and Analysis (2nd Edition). New York: Oxford University Press.

White, T. D. & Folkens, P. A. 2005. The Human Bone Manual. London: Elsevier Academic Press.

Dental Delights and Disability in Archaeology

26 Mar

I’ve recently had the joy of a dealing with a dental abscess affecting the left hand side of my mandible, and whilst I’m thankful for modern medicine I can only imagine the pain and frustration for pre-modern populations suffering with such an infection, especially those who didn’t have access to antibiotics and strong painkillers.  As such I haven’t posted properly for a while, and it might be a bit longer before I do.  Having had surgery to relieve the effect of the swelling and to drain the infection and remove two pesky teeth (with added complications courtesy of Fibrous Dysplasia), I’m once again learning how to chew (farewell 1st and 3rd left mandibular molars!).  It has also given me the time to think about the role of disability in the archaeological record and how it is approached by modern-day researchers.  What follows below is a very quick and brief overview of the main points of how disability has been approached in the archaeological sector and the changes therein.  Articles of interest are noted in the bibliography.

Dettwyler famously wrote a paper entitled ‘Can paleopathology provide evidence for compassion‘ (1991: 375-384, PDF embedded) that rightly questioned the interpretations of archaeologists and osteologists on the inferred aspects of care and compassion that disabled individuals from the archaeological record may or may not have received during their lifetimes.  The author cautioned that archaeologists and researchers are not ‘justified in drawing conclusions either about quality of life for disabled individuals in the past or attitudes of the rest of the community from skeletal impairment of physical impairment’ (Dettwyler 1991: 375).  This was a much-needed wake up call, and rightly raised questions in the realms of archaeology and palaopathology regarding how we viewed individuals, and how we analysed them.

The majority of disability studies before the Dettwyler (1991) article focused on disabled individuals as case studies, reported in journals and rarely integrated or investigated as part of the society or cemetery population they may belonged to.  Mays (2012) rightly investigated the impact of the relative value of individual case studies compared to quantitative and problem orientated population studies, and found that although the publishing gap had lessened between the two types, singular case studies still predominated.  Mays (2012) main contention is that individual case studies do little to further the advance of palaeopathology, something which Larsen (1997) effectively demonstrates throughout his book and review (2002), in the consideration of how palaeopathology can indicate society or cultural wide rituals, actions or lifestyles.

Since the publication of the Dettwyler paper there has been a slew of articles, journals and books dedicated to researching disability as evidenced from the skeletal and archaeological record, both from a bioarchaeological perspective and from a theory perspective (Battles 2011, Brothwell 2010, Hawkey 1998, Kleinman 1972, Vilos 2011, Wood et al. 1992).  Indeed the study of disability and the implications for affected individuals, their communities and societies, has moved on considerably since the descriptive days of Calvin Wells, especially in the consideration of the theory of ‘compassion’ as an evolutionary force in the primate family (Hublin 2009, Stewart et al. 2012), or as evidenced in other mammals (Fashing & Nyuyen 2011).

This is in accordance with the rise and debate of disability theory and studies in numerous other disciplines.  This has had real life applications in many areas of modern-day life, where multi-agented approaches to understanding,  recognising and implementing programs that are designed to raise awareness or life quality for disabled individuals.  Two prominent examples from the UK are the 2005 Disability Discrimination Act and the 2010 Equality Law where disability itself is given a legal definition, and here we come to a prominent problem in the archaeological and palaeopathological record itself.

Disability, as we would recognise it today, can mean both a physical and/or a mental impairment that can be substantial and lifelong, and it is worth noting some problems inherent in the archaeological record.  Firstly, in the archaeological record, we can only recognise physical disability when it has affected the skeletal remains of individuals, normally at a late and severe stage in the disease progression (Aufderheide & Rodriquez 1998, Waldron 2009, Wood et al. 1992).  As such, a large number of individuals with diseases or traumatic injuries that only affected the flesh will go unknown, and as such are unstudied.  Secondly, there is no universal or standard definition of disability that archaeologists and researchers use, it is solely up to the person/persons to define clearly and openly which definition they are using at the outset of their research (and there are a lot of definitions and models depending on which source you base your definition on).  Thirdly, the usage of terminology itself, such as the very word disability, can have vastly different connotations or implications for different populations and cultures (Battles 2011).

There may have been distinct differences as to who was considered disabled or not in historic and prehistoric cultures, and we should, as researchers, always be aware of observer bias ourselves (Dettwyler 1991).  As such researchers should always be clear who they are addressing, and the possible differences highlighted, where evidence is available, as to how a disabled person was treated within their culture when archaeological or cultural evidence is available.

To complicate the matter further is the ‘osteological paradox‘, as highlighted by Larsen (1997), Woods et al. (1992) and Wright & Yoder (2003) amongst others, which heavily influences the health status of skeletal remains that survive and that are then studied.  Therefore it should always be understood that no skeletal sample is entirely representative of their population, that there are many caveats (Hahn 1995, Roberts 2000).

Battles (2011) highlighted the need to move towards a more holistic approach to disability, to take advantage of different fields (including physical anthropology, sociocultural anthropology, experimental studies and archaeology itself) to understand disability at archaeological sites and affected individuals, to a model that integrates the data and insight of the various fields.  In particular Battles (2011) makes the salient point of noting the individuals  (largely females and sub-adults) that historically have been under-studied in archaeological and population analyses.

An important methodological update has been the advancement of a ‘Bioarchaeology of Care‘, as espoused by Tilley & Oxenham (2011), where a four stage assessment of an individual produces an assessment of the care needed for the disabled individual found in a Neolithic Vietnam community.  The stages are: (1) describing,  diagnosing and documenting the individual and site, (2) identify the clinical/functional impacts of disease or trauma, and determine if care was needed, (3) produce a model of care, and finally (4) interpret the implications for the individual and society, as well as possible indications for the identity and nature of both (Tilly & Oxenham 2011: 36).  It could be argued that other researchers have espoused the same sentiments (Roberts & Manchester 2010, Vilos 2011), but it is the clear initiation of the applying the model to individuals who fit the criteria that will hopefully produce further studies and elicit meaningful result which highlight this recent study as one to watch.  The Tilley & Oxenham (2011) model is particularly useful for prehistoric cases where there are no written or documentary sources.

Hawkey’s (1998) study of musculoskeletal markers (MSM’s) of a disabled individual from a New Mexico Pueblo culture highlighted the worth of applying existing osteological techniques to disabled individuals in order to assess the quality of bodily movement.  The modelling of the movement capable for this individual suggested that bodily manipulation, feeding, and the cleaning of this person was likely carried out by members of his culture (possibly family relatives, although this is conjecture) due to the severity of his disability (Hawkey 1998: 330).  Craig & Craig (2011) make extensive use of modern medical imaging to diagnosis a specific disease (fibrous dysplasia) in the case of a sub-adult from an English Anglo-Saxon site.  The striking bone expansion in the mandible is discussed within the social sphere of the community that the individual belonged.  The implications, via the the inference of position of the body within the grave, grave goods and grave location, and studies into Anglo-Saxon culture and social stratification give rise to the theory that the individual was not treated any differently due to his disability, although it is unknown if the disease led to the early demise of the individual (Craig & Craig 2011: 3).

Craig & Craig’s (2011) case study, and the above studies, highlight the use of modern medical literature and imaging technology in establishing a likely disease diagnosis, yet Brothwell (2010) rightly highlights the dangers of the differential diagnosis of diseases in skeletal remains at a macroscopic level.  Waldron’s (2009) palaeopathology handbook presents an ideal source on how to identify diseases that can lead to disability, but highlights the value of the differential diagnosis when the osteologist cannot be exactly sure of the disease.

The battery of scientific techniques used in archaeological investigations, including aDNA analysis, trace chemical analysis, and isotopic analysis amongst others, have become significantly refined within the past two decades, and are now allowing for a more nuanced understanding of individual and population dynamics (Brown & Brown 2011).  This includes the ability to analysis the movement of a person in a landscape within their lifetime (Marstellar et al. 2011), and to understand the changes in diet and the effects of diet on the body (Larsen 1997, Roberts 2000, Roberts & Manchester 2010). It also includes the ability to indicate the likely exposure of populations to various chemicals and diseases (Barnes et al. 2011), and exploration of how social structure (Bentley et al. 2012), and hence the role of the population or of the individual, changed through time.

Perhaps what the above studies cannot show, especially in prehistoric societies, are the actions of the disabled individuals themselves.  It is most likely that we will never know if they took an active interest in their society, if they took part, or how they felt as disabled individuals, or even if they saw themselves as disabled (Battles 2011, Hahn 1995).  Compassion  itself cannot be excavated (Dettwyler 1991), but with careful examination of the available evidence results can be produced that suggest that severely disabled individuals did survive past natural limitations.

The progress continually being made in the hard sciences and in the humanities continues to advance our knowledge of past populations via their skeletal remains and their cultural context.  The understanding of disability within an archaeological and osteological context provides the opportunity to investigate of how individual’s survived, and whether care was a key component (Hawkey 1998, Kleinman 1978, Tilley & Oxenham 2011).  This is a burgeoning area of bioarchological research, and when combined with a multidisciplinary approach, it opens up a wide range of interesting and diverse approaches and avenues.

Case Studies, Theories and Further Information:

Full articles are linked where possible, although a number hide behind Journal pay walls.

Aufderheide, A. C. & Roderiquez-Martin, C. 1998. The Cambridge Encyclopedia of Human Palaeopathology. Cambridge: Cambridge University Press.

Barnes, I., Duda, A., Pybus, O. G. & Thomas, M. G. 2011. Ancient Urbanization Predicts Genetic Resistance to Tuberculosis. Evolution. 65 (3): 842-848.

Battles, H. 2011. Toward Engagement: Exploring the Prospects for an Integrated Anthropology of Disability. Explorations in Anthropology. 11 (1): 107-124.

Bentley, R. A., Bickle, P., Fibiger, L., Nowell, G. M., Dale C. W., Hedges, R. E. M., Hamiliton,. J., Wahl, J., Francken, M., Grupe, G., Lenneis, E., Teschler-Nicola, M., Arbogast, R-M., Hofmann, D. & Whittle, A. 2012. Community Differentiation and Kinship Among Europe’s First Farmers. Proceedings of the National Academy of Sciences Early Edition. 1-5. (Early View).

Brothwell, D. 2010. On problems of Differential Diagnosis in Palaeopathology, as Illustrated by a Case from Prehistoric Indiana. International Journal of Osteoarchaeology. 20: 621-622.

Brown, T. & Brown, K. 2011. Biomolecular Archaeology: An Introduction. Chichester: Blackwell Publishing.

Churchill, S. E., Franciscus. R. G., McKean-Peraza, H. A., Daniel, J, A. & Warren, B. R. 2009. Shanidar 3 Neandertal Rib Puncture Wound and Palaeolithic Weaponry. Journal of Human Evolution. 57: 163-178.

Craig, E. & Craig, G. 2011. The Diagnosis and Context of a Facial Deformity from an Anglo-Saxon Cemetery at Spofforth, North Yorkshire. International Journal of Osteoarchaeology. (Early View doi: 10.1002/oa.1288).

Dettwyler, K. A. 1991. Can Palaeopathology Provide Evidence for “Compassion”? American Journal of Physical Anthropology. 84: 375-384.

Fashing, P. J. & Nguyen, N. 2011. Behaviour Towards the Dying, Diseased, or Disabled Among Animal and its Relevance to Palaeopathology.  International Journal of Palaeopathology. 1: 128-129. 

Hahn, R. A. 1995. Sickness and Healing: An Anthropological Perspective. New Haven: Yale University.

Hawkey, D. E. 1998. Disability, Compassion and the Skeletal Record: Using Musculoskeletal Stress Markers (MSM) to Construct an Osteobiography from Early New Mexico. International Journal of Osteoarchaeology. 8: 326-340.

Hublin, J. J. 2009. The Prehistory of Compassion. Proceedings of the National Academy of Sciences. 106 (16): 6429-6430.

Kleinman A. 1978. Concepts and a Model for the Compassion of Medical Systems as Cultural Systems. Soc Sci Med. 12: 85-93.

Knusel, C. J. 1999.  Orthopaedic Disability: Some Hard Evidence. Archaeological Review Cambridge. 15: 31-53.

Larsen, C. 1997. Bioarchaeology: Interpreting Behaviour from the Human Skeleton. Cambridge: Cambridge University Press.

Larsen, C. S. 2002. Bioarchaeology: The Lives and Lifestyles of Past Peoples. Journal of Archaeological Research. 10 (2): 119-166.

Marstellar, S. J., Torres-Rouff, C. & Knudson, K. J. 2011. Pre-Columbian Andean Sickness Ideology and the Social Experience of Leishmaniasis: A Contextualised Analysis of Bioarchaeological and Palaeopathological Data from San Pedro de Atacama, Chile. International Journal of Palaeopathology. 1 (1): 23-34.

Mays, S. 2012. The Impact of Case Reports Relative to Other Types of Publication in Palaeopathology. International Journal of Osteoarchaeology. 22: 81-85.

Roberts, C. A. 2000. ‘Did They Take Sugar? The Use of Skeletal Evidence in the Study of Disability in Past Populations’. In Hubert, J. (ed) Madness, Disability and Social Exclusion: The Archaeology and Anthropology of Difference. London: Routledge. 46-59.

Roberts, C. & Manchester, K. 2010. The Archaeology of Disease. Stroud: The History Press.

Stewart, F.A., Piel, A.K., O’Malley, R.C., 2012. Responses of Chimpanzees to a Recently Dead Community Member at Gombe National Park, Tanzania. American Journal of Primatology. 74: 1–7.

Tilley, L. & Oxenham, M. F. 2011. Survival Against the Odds: Modelling the Social Implications of Care Provision to the Seriously Disabled. International Journal of Palaeopathology. 1 (1): 35-42.

Vilos, J. D. 2011.  Bioarchaeology of Compassion: Exploring Extreme Cases of Pathology in a Bronze Age Skeletal Population from Tell Abraq, U. A. E. Master’s Dissertation. Las Vegas: University of Nevada.

Waldron, T. 2009. Palaeopathology. Cambridge: Cambridge University Press.

Wood, J. W., Milner, G.R., Harpending H. C., & Weiss, K. M. 1992.  The Osteological Paradox: Problems of Inferring Prehistoric Health from Skeletal SamplesCurrent Anthropology 33:  343-370.

Wright, L. E. & Yoder, C. J. 2003.  Recent Progress in Bioarchaeology: Approaches to the Osteological ParadoxJournal of Archaeological Research 11 (1): 43-70. (**An extensive bibliography of articles can be found in the bibliography of this article**).

My Readings…

13 Sep

Soon I’ll be moving down to Sheffield to study anew.  At the moment, this is my current core collection of books but I feel it will soon be expanded upon…

All the classics… just missing an anatomy book!

Before I left for Sheffield I picked up a DK guide to the complete human body today, alongside a copy of the Concise Book of Muscles; so I have plenty of hard reading and memorising ahead.  Now that I have recently arrived in Sheffield and had the introduction talk for the MSc in Human Osteology today (21st Sept),  I also gained the Human Anatomy Colour Atlas & Textbook by Gosling et al for the Human Anatomy module.  Now I have too much reading!

Any recommendations?  Please comment below!

Modes Of Transport

13 Jun

I have to agree with the writer Paul Theroux and his love of the train as the medium for travelling.  Although I have done nothing on his scale (read his books The Great Railway Bazaar or The Old Patagonian Express for a taste of his epic journeys) I, too, feel that the journey matters more then the destination.  I believe it to be a fine metaphor for life itself as well.

I found myself, as every Monday and Tuesday morning, pounding down the rail tracks on the way to York.  Half way through the journey I was joined by a bulky man sitting opposite me with a large camouflaged backpack,  bulging at the sides with this and that.  He flew at midnight tonight he said, six and a half hours to a land of camel spiders and the ever present threat of IEDs.  It was his second tour, six months long.  I wished him luck as he jumped out of the train doors at York station.

Replica Viking skates (credit: Hurstwic).

After a fast and thunderous wheel through the streets, I found myself at the archaeology base ready to start the day properly.  As normal the talk flowed easy and well through a variety of topics.  The big talking point of the day was the fact that Alice Roberts was on site to film for her Digging For Britain TV series.  The topic was Viking age York, and is due to be shown sometime around mid to late Summer on the BBC.  Although we didn’t really get to talk to her it was interesting to see archaeology being filmed for the masses.  Archaeological education and entertainment outreach helping to invigorate the youth of tomorrow, just as the summer season of excavations begin across the country.

After this brief interlude of celebrity archaeological intrusion, we carried on cleaning finds.  One of the more interesting finds today was the finding of a single Viking animal metatarsal skate.  As described on this interesting site, the skates (likely 10th Century AD) were used as a form of transport across ice during winter, and were tied on using leather thongs whilst the user pushed themselves across the ice with the probable help of two wooden poles.

On the example I helped clean, it was clear that the skate probably hadn’t been worn much as the underside was little worn.  Nevertheless it was interesting to see such an artefact in the flesh having only heard of them from other Scandinavian sites, both historic and prehistoric.

Viking skates made from bovine metatarsals in York (Image credit: YAT).

On my journey back to the railway station I passed the modern population of York and thought of those that had gone before.  The current site at Hungate criss crosses many different historic slices; from 3rd to 4th century AD Roman Eboracum, Viking Jorvik, to the later Medieval and Post Medieval city of York.  It is easy to think of past populations as pieces of pottery, discarded brick or tile but this not always the case.  As the quite frankly massive Lloyd Bank Coprolite shows, sometimes even the shit survives the journey through time!

The journey home was as pleasant a train ride as I’ve had.  I was thankful that the train slowed several times during the trip, as I had chance to look at and admire the Medieval agricultural technique of the ridge and furrows.  They are found throughout the North East, the landscape relics of a bygone age.  Today only the cows were happily lying down on them and chewing the grass.

Cows on the ridge and furrows, a feature of the medieval landscape and agricultural practices.

Skeletal Series Part 4: The Human Spine

30 Apr

As we started with the skull in this series of posts, we shall continue with the axial skeleton, and discuss the vertebral column (or spine) in the human skeleton.  The human spine consists of vertebrae that help support the back muscles, protect the spinal column, and provides the rod function for the axial skeleton (Mays 1999).  We’ll firstly discuss the moveable vertebrae, then move onto the hyoid, sacrum and coccyx elements.

On a personal note, I have difficulty with identifying vertebrae and reconfiguring them in the right order.  This is something I’m hoping to improve soon!  Meantime, here is a short guide…

As the basic excavation methods have already been discussed in the previous post, we will miss them out here.  Once again, care should be taken with handling, and it is unlikely all the elements would survive.  The hyoid bone is particularly liable to be missing or broken as it is a fairly small and fragile bone (Larsen 1997).

Vertebrae Anatomy, Terminology and Elements

The human spine consists of 33 vertebrae in total; 24 are considered to be part of the upper spine, whilst the other 11 are found in the Sacrum & Coccyx (discussed below).  The 24 vertebrae can be split into three separate groups based on morphology, spinal curvature and position; those of the Cervical, Thoracic & Lumbar vertebrae (White & Folkens 2005).  The vertebrae are often referred to by their first distinction, and by the number in that area.  So the second cervical vertebrae is referred to as the C2 etc.

The main bone landmark features of a typical vertebra are presented in the diagram below.  Please note that there are variations depending on the class of vertebrae under discussion.

Typical bone landmarks found on vertebrae and anatomical information (Eckalbar et al 2012. Scoliosis and Segmentation Defects of The Vertebrae. Developmental Biology. 1 (3): 402.)

The vertebrae in these groups are typically found as below (proximal to distal):

Cervical: 7 Vertebrae present.  The normal cervical vertebrae include interlocking vertebral bodies, with saddle shaped superior and inferior surfaces; alongside this the canal (see below) is triangular and of a similar size to the vertebral body (Mays 1999).  The spinous process are shorter than in thoracic and not as massive as lumbar vertebrae processes (White & Folkens 2005: 163).

Thoracic: 12 Vertebrae present.  The elements in this section of spine again increase in body size (vertebral body).  Each thoracic element articulates with a pair of ribs in the human skeleton.  It has been noted that ‘upper thoracic bodies are roughly triangular in a superior outline whilst the lower thoracic vertebral bodies are more circular’ (White & Folkens 2005: 170).  The vertebrae canal (or arch which the spinal column runs through posteriorly) are smaller relative to the vertebral body, and importantly, more circular than in cervical vertebrae (Waldron 2009).

Lumbar: 5 Vertebrae present.   Finally the vertebral bodies of the lumbar vertebrae once again increase in size from superior to inferior (as all vertebrae do).  They are the largest of all the unfused vertebrae, and should be easily identifiable by their size and features (larger spinous process, vertebral bodies, & smaller transverse process and lumbar arches) (White & Folkens 2005: 178).

It must be remembered that due to variation, an added or missing vertebra, is a possibility.  Between the individual vertebrae bones are intervetebral discs present.  In life, they help to provide movement between bones and act as ligaments.

Cervical, Thoracic & Lumbar Vertebrae & Anatomical Features.

As discussed above, there are three vertebrae types, as seen in the diagram above and below.  Important changes in the morphology and shape of these elements can be noted, thus each part can be ascertained to the differing thirds of the spine (White & Folkens 2005).  As it can be seen from the diagram below, the thoracic & lumbar vertebrae have a much more developed Vertebral Body (cementum in other animals), alongside a much more elongated Spinous Process.

Differences In Body Shape for Cervical (C4), Thoracic (T6) & Lumbar (L2) Vertebrae.

Distinctive Elements

The Atlas and Axis Vertebrae (diagram below), the first and second cervical vertebrae, are the most distinctive in terms of size and morphology.  The Atlas bone (C1) lies between the cranium (connecting with the condyles of the occipital bone) and the Axis  vertebrae (C2).  The atlas lacks a ‘vertebral body, a spinous process and has no articular disks either superior or inferior to it’ (White & Folkens 2005: 163).  The Axis bone also lacks a typical vertebral body.  It’s most distinctive feature is the odontoid peg, as seen in the diagram below.  This allows the head to rotate, moving the atlas about the odontoid peg of the axis bone (White & Folkens 2005: 169).

Features Of The Atlas (C1) & (C2) Axis Vertebrae

Transitional vertebrae include the sixth cervical vertebrae, which has a larger cementum (body) and a spinous process resembling a thoracic vertebrae.  The twelfth thoracic vertebrae resembles the eleventh vertebrae but the inferior articular facets assume the lumbar pattern rather than the typical thoracic pattern (White & Folkens 2005: 170).

The Hyoid bone (diagram below) is the located in the neck, immediately above the Adams apple on the anterior surface of the neck.  it is the only bone in the human body that does not articulate with any other bone whatsoever.  It consists of the body, the lesser horns and greater horns, as can be discerned in the diagram below (White & Folkens 2005: 155).  Unfortunately, it is often broken (fractured) during strangulation, and can be used as key indicator in murder cases.

Details of The Hyoid Bone

The Sacrum (diagram below) consists of five fused vertebrae in a wedge like shape at the bottom of the vertebral column.  These fuse in adolescents, and can consists of between four to six segments, although five is the normal average.  To both lateral sides are the pelvic bones (Os Coxa), whilst inferiorly lies the coccyx.

The Coccyx (diagram below) articulates distally to the Sacrum, and consists of 3 to 5 fused elements (variation is common).  It is the vestigial tail, and highly variable in shape.  In later life, the Coccyx may fuse to the Sacrum.  As with the above bone, the coccyx decreases in size inferiorly (White & Folkens 2005: 245).

Sacrum Terminology

Discussion of Osteoarthritis

As biped hominids, homo sapiens are at the mercy of numerous back problems.  The wear and tear, stresses and strains, that the vertebrae have to take are often manifested through various disease & maladies (Jurmain et al 2010).  Specifically, there is an increased susceptibility  in spinal joint disease.  Osteoarthritis is one such example, (OA) presenting in vertebrae that often occurs as a direct response to spinal stress (Roberts & Manchester 2010: 139).  The spine is recognised as ‘exhibiting a backward curve in the chest or thoracic region and a forward curve in the lumbar and cervical regions’; which lead to the C5, T8 & L4 vertebrae as being the most affected by joint disease (Roberts & Manchester 2010: 139).

These points are the areas of maximum and minimum stress, and this is seen as the variation in the frequency of OA in the spinal column.  As Waldron (2009: 27-30) states, ‘osteoarthritis is primarily a disease of the articular cartilage which breaks down as the disease progresses’.  The incipient factor is the enzymatic breakdown of the cartilage matrix, and affects the bone in the following ways.

The five main steps are outlined below:

1.  ‘Formation of new bone (after mixed signals from enzymes) around the margins of the joint; often called marginal ostephytes.

2.  Formation of new bone on the joint surface due to the vascularisation of the subchondral bone.

3. Pitting on the joint surface manifested as a series of holes on the joint surface.

4.  Changes in the normal contour of the joint, often widening and flattening of he contour.

5.  The production of eburnation, a highly polished area on the joint surface, usually sharply demarcated from the non-eburnated surface.  This area is sometimes grooved towards the motion and direction of the joint; presumably due to debris or crystals between the two articulating surfaces’ (Waldron 2009: 27-29).

Eburnation On The ‘Peg’ of the Axis Vertebrae (Shiny & Smooth Wearing)

Factors that are known to be important as precipitates to OA include age, race, sex, genetics, obesity, trauma and most importantly, movement itself.  Age is particularly important, as at the older standard range of human health there is scarcely anyone left with normal joints (Roberts & Manchester 2010, Waldron 2009).  An example of OA occurring in populations will now be discussed.  Lovell (1994) discuss a site in Pakistan, dating from 4000-5000 years ago (Bronze Age), where a pattern of OA was seen in the population.  The disease was noted as mechanical in nature (as normal), but focused on the cervical vertebrae.  This may be a reflection of activity in which the people carried heavy loads upon their heads (Roberts & Manchester 2010: 141).

The excavation of medieval rural site of Wharram Percy, in North Yorkshire, uncovered a large series population (May 1999).  Examination of features on the spinal column indicate OA was prevalent in the population at around 55 per cent for males and 39 per cent for females.  Because the site was rural in nature, and had indication of being used as an agricultural centre, it was identified that this population had developed OA through their lifestyle choices (Roberts & Manchester 2010: 143).  Useful as these sites, and features are, it should be reminded that ‘spinal joint disease was not the ideal part of the skeleton to observe as a marker of activity-related stress’ (Roberts & Manchester 2010: 143).

Bibliography

Jurmain, R. Kilgore, L. & Trevathan, W.  2011. Essentials of Physical Anthropology International Edition. London: Wadworth.

Larsen, C. 1997. Bioarchaeology: Interpreting Behaviour From The Human Skeleton. Cambridge: Cambridge University Press.

Mays, S. 1999. The Archaeology of Human Bones. Glasgow: Bell & Bain Ltd.

Roberts, C. & Manchester, K. 2010. The Archaeology of Disease Third Edition. Stroud: The History Press.

Waldron, T. 2009. Palaeopathology: Cambridge Manuals in Archaeology. Cambridge: Cambridge University Press.

White, T. & Folkens, P. 2005. The Human Bone Manual. London: Elsevier Academic Press.

Skeletal Series Part 3: The Human Skull

22 Apr

In this post I will be discussing the basics of the human skull; its anatomical features, number of elements, terminology, key functions and how to handle a skull.  Alongside the earlier blog on variations in human skeleton and the ethics that should be considered, this should prepare the user for interaction and identification of physical remains.

A skull in situ. From the Gadot archaeological site in Israel.

Individual elements found in the human skull, individual elements discussed below (Pearson Education 2000).

 The human skull is one of the most complex structures in the human skeleton.  It houses the foundations for the sense of smell, sight, taste & hearing, alongside the housing of the brain.  It also provides the framework for the first processes of digestion by mastication of food with the use of the teeth anchored in mandible and maxilla bones (White & Folkens 2005: 75).  White & Folkens (2005) go on to note that it is of value that the key anatomical landmarks of the skull are noted.  These include the Orbits of the eye sockets, the Anterior Nasal Aperture (nose hole), External Auditory Meati (ear canals), the Zygomatic Arches (cheek bones) along with the Foramen Magnum (base of the skull).  It is by these landmarks that we can orientate the skeletal elements if they are disarticulated or have been broken (White & Folkens 2005: 75).

Excavation

Particular care should be taken when excavating the skull, or any human skeletal element.  Careful consideration should be made of its location, burial type, any nearby skeletons, and of course any different stratigraphic (colour/cut/fill) features present should be noted (Mays 1999).  As this is the only chance to lift the skeleton since deposition, careful notes should be made on first impression and any post depositional changes that can be immediately identified.  Careful sieving of the soil matrix around the skull should take place, to help retain any small fragments of bone or lose teeth (whole and partial fragments) (Mays 1999).  Differential preservation, dependent on deposition & burial environment conditions, will mean that it is likely sections of the skull will not survive.  These are often the small, delicate bones located inside the cranial-facial portion of the skull.  The likeliest to survive portions are the mandible and the cranial plate elements because of their tough biological nature.

Handling

When handling the skull it should be noted of the above major landmarks.  For example, you will not damage the skull whilst carefully holding it in both your hands but if you hold it by the orbits you are liable to damage the surrounding bone.  The foramen magnum is usually stable and strong it to withstand creeping fingers as a hold place.  Whilst studying the skull on a desk, a padded surface should be provided for it to rest upon.  Care should be taken when handling the mandible, and temptation should be resisted in testing the mechanical properties of the surrounding bone (Mays 1999).

Anatomical Planes

For use between comparative material, it is useful to use a standardized set of viewing planes.  The human skull is often viewed via the Frankfurt Horizontal (White & Folkens 2005).  The FH is a plane of three osteometric points conceived in 1884 (see above link).  The skull is normally viewed from six standard perspectives.  These include norma verticalis (viewed from above), norma lateralis (viewed from either side), norma occipitalis (viewed from behind), norma basilaris (viewed from underneath) and norma frontalis (viewed from the front). Thus, when considered with osteometric points, measurements can be taken and compared and contrasted (White & Folkens 2005: 86).

Cranial Terminology and Elements

  1. The Skull refers to the entire framework including the lower jaw.
  2. The Mandible is the lower jaw.
  3. The Cranium is the skull without the mandible.
  4. The Calvaria is the cranium without the face portion.
  5. The Calotte is the calvaria without the base of the skull.
  6. The Splanchnocranium is the facial skeleton.
  7. The Neurocranium is the braincase.

The skull in infants is made up of 45 separate elements but as an adult it is normally made up of 28 elements (including the ear ossicles) (White & Folkens 2005: 77).  The Hyoid bone (the ‘voice box’ bone) is generally not included in the count of skull bones.  The identification of the elements can be made hard as idiosyncratic differences, and fusion between plates of the cranium, can lead to differences.  A number of elements in the human skull are paired elements; simply that they are part of two identical bones in the skull.  Alongside this there are also separate elements.  The list is below-

Paired Elements

  1.  Parietal bones- Located form the side and roof of the cranial vault.
  2. Temporal bones- Located laterally and house the Exterior and Interior Auditory Meatus.  They also include the Temporomandibular Joint (TMJ for short), the
  3. Auditory Ossicles– The malleus, incus and stapes (6 bones altogether) are located in both of the ears, very near the temporal bones (Very often never recovered in archaeological samples).
  4. Maxillae bones- Located proximal to the mandile, houses the upper jaw.
  5. Palatine bones- Located inside the mouth and forms the hard palate and part of the nasal cavity.
  6. Inferior Nasal Conchae bones- Located laterally inside the nasal cavity.
  7. Lacrimal bones- Located medially in the orbits.
  8. Nasal bones- Located distally to the frontal bone, helping to form the upper nose.
  9. Zygomatic bones- They are the cheekbones.

‘Norma Lateralis’ view of the human skull (Pearson Education 2000).

Single Elements

  1. Frontal bone- Located anterior, it is the brow of the skull.
  2. Occipital bone- Located to the rear of the skull, houses the Foramen Magnum.
  3. Vomer bone- Located in the splanchnocranium, and divides the nasal cavity.
  4. Ethmoid bone- A light and spongy bone located between the orbits.
  5. Sphenoid bone- Located inside the front of the splanchnocranium, a very complex bone.
  6. Mandible bone- The lower jaw.

‘Norma Frontalis’ view of the human skull, note the large orbits (Pearson Education 2000).

‘Norma Basilaris’ view of the human skull, note the foramen magnum where the spinal chord enters the skulls to connect with the brain (Pearson Education 2000).

‘Intracranial Superior’ view of the human skull, again note the foramen magnum where the spinal chord enters the skull to join the brain and the thickness of the outer and inner cortical bones of the skull (Pearson Education 2000).

General Discussion

The human skull is a complex part of the body.  It is key in identification of sex by the size of the Mastoid Process, Supraorbital Torus, tooth size, and the squareness of the mandible amongst others; it can also be used in describing age at death by tooth wear, Cranial Suture closure and general porosity of the bone (Roberts & Manchester 2010, White & Folkens 2005, Jurmain et al 2011).  A later post will detail exactly how in further detail.

It has also changed as our species, Homo Sapiens, evolved from earlier hominids.  The morphology of the human skull has certainly become more gracile, and as an indicator and outcome of the agricultural revolution, it seems our mandibular size and muscle robusticity has slowly become less pronounced (Larsen 1999: 230, Jurmain et al 2011).  As Larsen remarks (1999: 226), it is the influence of environment and mechanical behaviour that helps determine the morphology of the skull, alongside considered genetic factors.  It is important we keep this in mind as we look at archaeological material.  Studying population trends in both temporal, cultural and geographic contexts can have important results and can also highlight long term trends.

One such trend is the discussion that a change to a more ‘globular cranial change in the Holocene represents a compensatory response to decrease in functional demands as foods become softer’ (Larsen 1999: 268).  This is underscored in archaeological populations worldwide that consumed abrasive foods with populations that consumed non abrasive foods.  By being affected by food production processes & the nature of the food itself, the morphology of the cranial facial biomechanics has changed to adjust to differing food sources.  This change has influenced cranio-facial size and morphology, occlusal abnormalities, tooth size, dental trauma, and gross wear from masticatory and non-masticatory functions (Larsen 1999: 269, Waldron 2009).

Case Study: A Mesolithic-Neolithic population trend in Ancient Japan

One example of the importance of cranial studies, and of the skull in general in archaeology, is the discussion of population change during the end of the Jomon period of Japan.  Lasting roughly from 14,000 BC to 300 BC, the Jomon culture has evidence for the earliest use of pottery in the world, and made extensive use of the large variety of environments in the Japanese archipelago (Mithen 2003).  This culture has been classed as largely hunter-gather-forager in lifestyle, until roughly the Yayoi period around 300 BC; when the adoption to agriculture was fully implemented with intensive rice agriculture, weaving and the introduction of metallurgy (Mays 1998: 90).

The evidence suggests that the Yayoi were settlers from mainland Asia, with the evidence from craniometric studies and dental studies of both Jomon and Yayoi populations, alongside a comparative study with the modern day aboriginal Ainu people who inhabit the island of Hakkaido, north of mainland Japan.  The Ainu population themselves maintain that they are the descendents of the Jomon people, and with the skeletal data of skull morphology in the modern population compared to the Jomon archaeological data set, the evidence seems to match (Mays 1998: 92).  Population pressures during the end of the Jomon period and movement of the Jomon culture is therefore suggested as a geographic movement.  The skeletal data from the modern day Ainu population, concentrated in Hokkaido, provide evidence of a Jomon movement north due to pressure, as mainland Japanese modern population cranial measurements shows a mix of origin (Mays 1998: 90).

The importance of this work highlights the movement of the adaptation of agriculture in a relatively late time frame, in comparison to mainland Asia and Europe.  The palaeoenvironmental evidence suggests the richness and diversity of the Japanese archipelago, with heavy densities of the Jomon population in 3500 BC located in central and eastern Japan (Kaner & Ishikawa 2007: 2).

Stable village sites with pits dwellings, storage areas and burial facilities have been excavated and studied, yet there is only a hint of cultivating nuts and plants.  Ongoing date conflicts with AMS results from human and animal bone have suggested the impact of the Yayoi culture to be pushed back to 1000 BC or 900 BC.  However the results could be contaminated with the ‘marine radiocarbon reservoir effect’, a natural distortion of dates and thus a possible need to recalibrate existing dates (Kaner & Ishikawa 2007: 4).  The outcome of the timing of adoption of agriculture in the Late Jomon/Yayoi period is still hotly debated. Yet the archaeological and osteoarchaeological evidence presents a hunter gather society managing to thrive without agriculture in diverse environments until later cultures and migrations of people came into contact with the Jomon culture (Mays 1998).

Further Information

Bibliography

Jurmain, R. Kilgore, L. & Trevathan, W.  2011. Essentials of Physical Anthropology International Edition. London: Wadworth.

Kaner, S. and Ishikawa, T. 2007. ‘Reassessing the concept of ‘Neolithic’ in the Jomon of Western Japan’. Documenta Preahistorica. 2007. 1-7.

Larsen, C. 1997. Bioarchaeology: Interpreting Behaviour From The Human Skeleton. Cambridge: Cambridge University Press.

Mays, S. 1999. The Archaeology of Human Bones. Glasgow: Bell & Bain Ltd.

Mithen, S. 2003. After The Ice: A Global Human History, 20,000-5000 BC.London: Weidenfeld & Nicolson.

Roberts, C. & Manchester, K. 2010. The Archaeology of Disease Third Edition. Stroud: The History Press.

Waldron, T. 2009. Palaeopathology: Cambridge Manuals in Archaeology. Cambridge: Cambridge University Press.

White, T. & Folkens, P. 2005. The Human Bone Manual. London: Elsevier Academic Press.

Skeletal Series Part 1: Bone Variation & Biomechanics

10 Apr

In the following series of blog posts I aim to cover each of the main skeletal elements.  Each post will have a single focus on a bony element, from the skull down to the bones of the foot.  Firstly though we must deal with the variation that human osteologists and bioarchaeologists will see in individual skeletons, and in a population series.  It is both useful and informative to learn the differences and the effects caused by the 4 main variation factors in the morphology of human bones.  As it is by ascertaining the degree of influences that the variation factors can cause that we can begin to understand the individual, and the skeletal series of a population, in a more informative and considered way.  The second part of this entry will focus on the basics of biomechanics, and the influences certain lifeways can have on bone.

The basic biology of bones was previously discussed in this post here, and of teeth here.  Bone in its natural state must be recognised as a changing living organism throughout life that responds to stress, both nutritional and mechanical, and remodels accordingly.  It is also must be remembered that bone is a composite material, and is able to heal itself.

Variation 1 : Ontogeny

Ontogeny is simply growth and development of an organism, in this case Homo sapiens.  The archaeological record of skeleton remains include unborn individuals right through to individuals in their 70th year and beyond.  Typically there are 7 classification groups of human age groups.  They run from Fetus (before birth), Infant (0-3 years), Child (3-12 years), Adolescent (12-20 years), Young Adult (20-35 years), Middle Adult (35-50 years), and Old Adult (50+ years) (White & Folkens 2005: 364).  Differences in bone structure, and in the growth of different bone elements often manifest themselves in changes in size and shape.

Adult with Two Juvenile Remains, From Southern Sahara

Basic Growth Profile for Homo Sapiens, Notice the Large Cranium and the Way the Body Catches Up.

Variation 2: Sexual Dimorphism

Humans are sexually dimorphic, that is there are differences between the female and male body size.  Although not as distinct between our cousins such as the gorillas, female human skeletal remains are relatively smaller in both bones and teeth size (Jurmain et a 2010).  Such skeletal variation is also manifest in the requirement of reproductive functions in the female skeleton, thus we are also often able to tell sex from skeletal remains (White & Folkens 2005: 32).

Generalised Male:Female Sexual Dimorphism

Variation 3: Idiosyncractic Differences

The idiosyncratic  (or individual) differences found in skeletons are simply natural variations, in the understanding that every body is different, and rarely are people exactly the same (identical twins excluded).  Idiosyncratic differences in bone affect the size and shape of the bone, and the topography of the bone surface.  Again, such variation is very common in human skeletal remains (White & Folkens 2005: 32).

Disarticulated human bone from the site of Armana, ancient Egypt.

Variation 4: Geographic or Population-Based

As White & Folkens point out ‘different human groups can differ in many skeletal and dental characteristics’ (2005: 32).  Thus this geographic variation can be employed to assess population affinities between skeletal series.  This trait can be quite useful in determining commingling of certain populations in prehistoric skeletal series as certain environmental and genetic traits can be passed on.

Biomechanic Basics

So these are the four main variations we should be aware of when we are looking and studying individual skeletons or a series of a population.  By considering these four main variations we can study the individual’s life pathway alongside other lines of investigation.  What we must also take into account next are the basics of biomechanics.  Biomechanics is the application of engineering principles to biological materials, whilst remembering that bone can remodel and change according to pressures put upon the bone.  As Larsen states that ‘the density of bone tissue differs within the skeleton and within individual bones in response to the varying mechanical demands’ (1997: 197).  It must be remembered that the response of human bone to ‘increased loading is in the distribution of bone (geometric) rather than density or any other intrinsic material property of bone’ (Larsen 1997: 197).

Importantly it is noted that Human bone is anisotropic, meaning its mechanical properties vary according to the direction of the load.  Importantly, Wolff’s Law highlights how bone replaces itself in the direction of functional demand.  A classic example of the remodelling capabilities of bone is that of the tennis player who has thicker cortical bone in their dominant arm.  This manifests itself in thicker cortical bone alongside hypertrophy of the muscle attachment sites.  One study carried out found that ‘males have a 35% increase in the cortical bone in the distal humerus of the playing arm vs the non-playing arm’, helping to exemplify Wolff’s Law (Larsen 1997: 196).  That study was an example of bilateral asymmetry humeral loading.  Alongside, it is the action of the main forces acting on human bone that help to change the bone, these  include a) compression, b) tension, c) shear, d) torsion & E) compression + tension+ bending.

Wolff’s law states that healthy load bearing bone (LBB) responds to strain by ‘placing or displacing themselves (at a mechanical level) in the direction of the functional pressure, & increase or decrease their mass to reflect the amount of functional pressure’, often muscular strain and/or weight bearing pressures (Mays 1999: 3).  As a part of this Frost (2004: 3) argues that the ‘mechanostat’, a tissue level negative feedback system, involves ‘two thresholds that make a bone’s strains determine its strength by switching on and off the biologic mechanisms that increase or decrease its strength’.  However, Skerry (2006: 123) has argued that there are many ‘mechanostats’ operating on the LBB and that different elements throughout the skeleton require different strain magnitudes for maintenance. Furthermore Skerry (2006: 126) also notes that differences are apparent between the sexes, and that genetic constitution, concomitant disease, exercise & activity patterns must be considered.

A recent article has also highlighted how the femoral neck width of obese people changes to accommodate the added weight.  In this case the width of the femoral neck has increased to dissipate weight throughout the bony area by increasing surface area and strength through redistribution of bone.  This is an example of active bone remodelling adapting to changes that the person has gone through in life.

An archaeological example of the above will now be taken from Larsen 1997.  ‘In the Pickwick Basin of northwestern Alabama, analysis carried out on both femora and humeri cross-sectional geometry has helped to reveal a number of differences between earlier Archaic Period hunter-gatherers and later Mississippian Period agriculturalists‘ (1997: 213).  From the femora measurements it seems that the both female and male agriculturalists had a greater bone strength, whilst analysis of male humeri shows little difference between the two series.  This has helped to show that activity levels increased for males but only in the lower limbs, as evidenced by the cross-section geometry.  However, for females of both time periods both humeri and femora strengths increased.  The article cited in Larsen (1997), Bridge 1991b, findings indicate that changes are from a greater range of activity undertaken by females than males.  With palaeopathological signs of osteoarthritis, it is concluded that the shift to food production,in particular maize production, may have had a relatively greater impact physically on women in this setting.

The next post will focus on ethics in human osteology, and from there we will consider each of the anatomical skeletal elements in context of their relative limb.

Bibliography

Frost, H. M. 2004. (A 2003). Update on Bone Physiology and Wolff’s law for Clinicians. Angle Orthodontist.  February 2004. 74 (1): 1-15.

Jurmain, R. Kilgore, L. & Trevathan, W.  2011. Essentials of Physical Anthropology International Edition. London: Wadworth.

Larsen, C. 1997. Bioarchaeology: Interpreting Behaviour From The Human Skeleton. Cambridge: Cambridge University Press.

Mays, S. 1999. The Archaeology of Human Bones.Glasgow: Bell & Bain Ltd.

Skerry, T. M. 2006. One Mechanostat or Many? Modifications of the Site-Specific Response of Bone to Mechanical Loading by Nature and Nurture. Journal of Musculoskeletal & Neuronal Interaction. 6 : 122-127. (Open Access).

White, T. & Folkens, P. 2005. The Human Bone Manual. London: Elsevier Academic Press.