Archive | Femur RSS feed for this section

Skeletal Series Part 10: The Human Leg

15 Mar

We shall continue our look at the human skeleton with the next installment of the Skeletal Series blog posts with a consideration of the leg elements.  Previously covered was the hip and we shall now cover the femur (upper leg), patella (kneecap) and the tibia and fibula (the two lower leg elements).  The evolution of the leg mirrors that of the arm, from ancient fins to rod bearing segments, and as per the arm the leg contains a single upper bone with two lower bones making up the limb ending in the quite unique foot or Pes (White & Folkens 2005: 255).

The femur is the human body’s longest and sturdiest bone that helps to take the whole weight of the body during ambulation (Schwartz 2007: 151).  The tibia is the larger of the lower leg bones and it is easier to tell it apart from its slimmer lateral partner, the long and angular fibula.  The patella is the body’s largest sesamoid bone, safely ensconced in its muscle pouch in the anterior portion of the knee.  The human knee is particularly interesting as it ‘locks’ when stood straight up and unlocks with the aid of the popliteus muscle by laterally rotating the distal femur, which helps critically stabilise the knee.

The basic bones of the human leg (Image credit: Sheri 2012).

Excavation

During excavation of the supine skeleton in-situ, the lower limb bones tend to survive well because of their structural design and bone density.  In extended burials, and dependent on burial and soil conditions, the lower limb bones are often well-preserved and relatively easy to distinguish from the rest of the body.  As always, care must be taken when excavating the soil on top of and around the lower body.  The fibula can often be found fragmented or broken due to its lateral positioning and the effect of the weight of the soil and associated tibia lying close to it (Larsen 1997).  Even in cremated or burned skeletal tissue samples, particular features and landmarks of the lower limb long bones can easily be identified, and sometimes even sided as larger fragments can sustain slightly higher temperatures and minimal warping (White & Folkens 2005).

A medieval cemetery excavation during the 2007 Brodsworth community project (Image credit: the universities of Hull & Sheffield field school).

Leg Anatomy and Elements

The lower limb in the modern human is an interestingly adapted limb to bipedal walking, and as such it has changed anatomically from our nearest cousins (the great apes) to cope with our locomotion (Jurmain et al. 2011).  In this section we’ll cover the basic gross anatomy of each bone with a more in-depth look at the knee component after.  As mentioned elsewhere (and on this blog herelong bone growth is typically through the distal metaphysis (distal border of the diaphysis of the limb) and its epiphysis through the growth plate.

Growth of the long bones in a juvenile knee joint (the femur is located proximally, with tibia distal and fibula laterally. (Image credit: Danna 2011).

Femur

The femur, as stated, is the longest limb bone with several distinctive bony elements.  It is a fairly distinct bone with a high level of robusticity and dense, compact bone due to it being the main supporting limb doing ambulation.  The head of the femur fits into the acetabulum of the hip bone (ilium, ischium and pubis bones).   Unlike the humerus and the glenoid cavity joint, it has a direct ligament attachment between femoral bone and acetabulum, the ligamentum teres, which fits it snugly from the fovea capitis depression on the femoral head into the hip joint, helping to stabilise the joint (White & Folkens 2005: 255).  It is also heavily walled with muscles, from the trunk of the torso down to the knee, with the gluteal (lateral-posterior),  adductors (medial), quadriceps (anterior) and hamstring (posterior) muscle groups acting on the bone at various points (Gosling et al. 2008).  

Main anatomical landmarks of the femur.  For further information see Hawks 2011.

The main osteological features found on the femur include the greater and lesser trochanter’s, which are found in the proximal half of the femur, just below the femoral neck.  The greater and lesser trochanter’s act as muscle attachment sites for the gluteal muscles, amongst others, and sometimes a third trochanter can been seen just distal of the lesser (White & Folkens 2005).  Directly posterior, and running down the length of the shaft of the femur, is the linea aspera, one of the main attachment points for a variety of muscles, including the vastus and adductor muscle groups.

At the proximal femoral end the linea aspera collects the spiral, pectineal and gluteal lines (White & Folkens 2005: 257).  The lateral and medial condyles mark the distal articular surface with the tibia bone of the lower limb.  Alongside the medial edge of the medial epicondyle (just above the medial condyle) lies the adductor tubercle, the insertion point for the adductor magnus muscle (Gosling et al. 2008: 260).  The femur can be easily sided as the trochanters are medial and posteriorly positioned, with the linea aspera running directly posteriorly and the adductor tubercle located medially on the medial epicondlye.  The mid-section shaft of the femur is tear shaped, with the round body in the anterior position and the top of the  ‘tear’ pointing posteriorly.

Patella

The patella is the human skeletal systems largest sesamoid bone, and can be found in the anterior muscular pouch on the knee joint, anchored by the quadriceps tendon and patellar tendon on the distal anterior femoral surface (see diagram below).  It does not attach or articulated directly with any other bone.  The patella functions to ‘protect the intricate muscles and ligaments inside the knee joint, to increase area of contact between the patellar ligament and the femur, and to lengthen the lever arm of the quadricep muscles’ (White & Folkens 2005: 270).  The apex of the patella is the most distal point of the bone, and the smooth posterior articular facet rides the ligaments and muscles located anteriorly of the distal femur.

The complex knee joint and associated musculo-skeletal anatomy.  See Roberts & Manchester (2010) for palaeopathological lesions of the knee, especially osteoarthritis. (Image credit: Wikipedia 2012).

Tibia

The tibia is a distinctly shaped bone with an proximal medial and lateral condyles, medial and laterally intracondylar eminence’s (set posteriorly on the superior surface), an anterior proximal tibial tuberosity, the curved ‘tri-blade’ of the body (anterior, medial and posterior crests, with the medial malleolus marking the distal extremity of the bone (White & Folkens 2005: 273-79).  The landmarks on the tibia represent muscle origin and insertion points, such as the soleal line on the posterior aspect of the proximal tibia, which represents the soleus muscle origin.  The tibia is connected to the laterally positioned fibula with a strong interosseus membrane connecting the two throughout the length of the fibula, with articulations at the proximal and distal segments of the tibia (Gosling et al. 2008: 277).  Distally, the tibia articulates with the talus, the first tarsal bone of the foot.  To easily side the tibia, the malleolus is located on the medial distal aspect of the tibia, and the tibial tuberosity represents the anterior facing proximal end of the bone.

Labelled Tibia and Fibula.

The main anatomical landmarks of the right tibia and fibula, with the anterior position on the left and the posterior on the right hand side. (Image credit: Wikipedia 2012).

Fibula

The fibula is the thinner of the two lower legs bones, and does not bare any substantial weight (White & Folkens 2005).  It’s primarily importance is providing the lateral border of the ankle joint, with which it articulates with the calcaenous bone.  The head of the fibula, located superiorly, can be easily complicated with the distal malleolar articular surface, and to add to the woes of identification, the body of the fibula, without the proximal or distal segments, is nearly impossible to identify because of its irregularity.  The interosseous crest is located medially, and serves as the attachment for the interosseus membrane which spans between the length of the tibia and fibula.  To side an intact fibula quickly, use the posterior facing malleolar fossa, which can be found on the distal articular surface of the fibula.  The fibula has also been used as marker of sex (Sacragi & Ikeda 1995) and although this method is rarely used, it could be useful in a forensic or archaeological context where the skeletal remains may be limited.

Further Information

  • Although not mentioned here, please take the time to get associated with the fleshy articular pads between the femur and tibia (be aware as this is a fleshed photo).

Bibliography

Gosling, J. A., Harris, P. F., Humpherson, J. R., Whitmore I., & Willan P. L. T. 2008. Human Anatomy Color Atlas and Text Book. Philadelphia: Mosby Elsevier.

Hawks, J. 2011.  Femur: major landmarks and how to side it. From www.johnhawks.net. Accessed 2012.

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.

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

Sacragi, A & Ikeda, T. 1995. Sex Identification From The Distal Fibula. International Journal of Osteoarchaeology. 5: 139-143. (access required).

Schwartz, J. H. 2007. Skeleton Keys: An Introduction to Human Skeletal Morphology. New York: Oxford University Press.

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

An Introduction to Fibrous Dysplasia & McCune-Albright Syndrome

28 Oct

Definition of Fibrous Dysplasia: ‘Fibrous dysplasia is a non-inherited metabolic bone disease in which abnormal differentiation of osteoblast maturation (which) leads to replacement of normal marrow and cancellous bone by immature bone and fibrous stroma’ (Fitzpatrick et al 2004: 1389).  Fibrous Dsyplasia (FD) can be described as either monostotic (one) or polyostotic (many), depending on how many bones are affected by the disease.  Fibrous Dysplasia lesions are often displayed as having a ‘ground glass‘ appearance on x-rays and are a distinctive radiographic feature of the disease, although it is not pathognomonic of it (Waldron 2009).  It is also noted that pathological fractures are a key defining feature of polyostotic Fibrous Dysplasia (Marsland & Kapoor 2008).  FD is described as a rare disease, with the monostotic form being more prevalent than the polyostotic form.

Definition of McCune-Albright Syndrome:  McCune-Albright Syndrome (MAS) was originally typically diagnosed and recognised when a person had any of the two of the triad of the following symptoms: polyostotic Fibrous Dysplasia, Cafe-au-lait marks and/or precocious puberty.  However it was later recognised that ‘endocrinopathies, including hyperthyroidism, growth hormone excess, renal phosphate wasting with or without rickets/osteomalacia, and Cushing Syndrome’  could be found in association with the original triad (Dumitrescu & Collins 2008: 1).  In all three systems (skin, skeletal & endocrine), the presentation and abnormality can be highly variable from person to person depending on the tissues involved and the extent of the involvement (OMIM-see below).  Estimated prevalence is 1/100,000 to 1/1,000,000, it is such a wide margin because no thorough prevalence study has been carried out in recent times (Dumitrescu & Collins 2008: 1).

————————————————————————————————————————————————–

As a person who happens to have McCune Albright syndrome, to have known to have it from the first years of life, I have become somewhat forgetful of its origin: that somewhere in the early postzygotic  divisions of my life, the disease appeared and became a part of me.  Although I am aware each day of the ramifications that the mutation of the GNAS1 gene has caused I often consider myself lucky.  Lucky in the fact that in my case it has only led to broken bones and various surgeries rather than the full expression of the endocrinopathies that can occur.  I use a wheelchair for everyday mobility with limited use of crutches, mostly used for aiding inside mobility (and sometimes excavations!).

In my personal case, the disease has most affected the main weight-bearing bones of the lower limbs (fairly typical as they are the stress bearing bones, prone to fracture from weakened bone architecture).  Generally speaking,the long bones of the appendicular skeleton tend to be bowed naturally with a pathological weakness due to the lack of normal bone density and high bone cell turnover, with the aforementioned bone lesions occurring spontaneously which sometimes lead to fracture.  This includes the bilateral deformity of the femora with which I’ve had numerous pathological fractures (Five natural transverse fractures, five elective surgery initiated) on both the left and right sides, alongside a number of fractures of the right tibia and fibula (including both transverse and hairline fractures), two on the right humerus and the 5th metatarsal in the right foot.  The shepherd’s crook deformity is the common bowing deformity with varus angulation of the proximal femur (Fitzpatrick et al 2004: online).

As stated the primary bones affected by the MAS pathological fractures are typically located in the appendicular skeleton and include the following bones in order of prevalence first:  a) femur, b) tibia, c) fibula, d) humerus and e) the ribs.  It can also affect the craniofacial skeleton with distinct abnormalities in the amount of bone growth and deformity; however this tends to lessen with age after the primary and secondary growth periods (adolescence and sexual maturity), or ‘burn out’ as it is often called by medical specialists (Dumitrescu & Collins 2008: 8).

‘An example of the shepherds crook’ deformity of the femoral neck (coxa vara) with internal fixation.

My experiences of living with McCune Albright syndrome has included numerous hospitalizations due to fractured bones and planned corrective surgeries.  This has also included large amounts of time stuck in my old friend the Thomas Splint in bed bound traction, alongside enduring a host of various corrective surgical procedures to improve the angulation of both femoral necks.  Although the initial idea following a number of fractures was to treat the femoral deformities with an Ilizarov apparatus by manipulating the bone growth every day, it was quickly decided that an intramedullary rod (nicknamed the Sheffield Rod), carried out in conjunction with osteotomies to correct the femoral neck angle during surgery, would be a much safer and further reaching goal in stabilising both femoral necks in the long term.  (A rather wonderful digital video of a rod being inserted/hammered in can be viewed here).  Five major elective intramedullary rod surgeries later (3 for the left femur and 2 for the right femur!), and it seems as if they have thus far stabilised each femoral shaft/neck enough for them not to fracture again.  However this is also due to using the wheelchair much more extensively than before!

I also have had surgery to stabilise the right tibia and fibula.  This was decided after having undergone three accidental fractures of the right tibia and fibula with a space of 5 years (when the tibia breaks the fibula often follows because of their connection via the interosseous membrane), with each fracture requiring many months in plaster in order for the bone to heal.  Again this surgery included osteotomies of the tibia and fibula to improve the angle of the bone (and thus improve the bio-mechanical loading of the lower leg) and included the fixation of the tibia by means of a titanium plate.  It was hoped that an intramedullary rod could be inserted into the tibia after the tibial osteotomy but the risk of massive blood loss (an outcome of the porous bone and increased heartbeat/blood flow) and the presence of porous cortical bone meant that the tibia was probably unlikely to be able to ‘hold’ the rod in place.

I have also fractured the right humerus twice, with the second transverse fracture resulting in the fixation of the humerus with a permanent titanium plate and associated screws.  This is similar to my right tibia which has a permanent titanium plate and screws to fixate the bone and alleviate some of the pressure of walking.

I have undertaken treatment using biphosphonphates (in my case the drug pamidronate) to increase the bone density itself over a number of years in the past when I was a teenager, but the resultant bone density scans (taken at intervals before, during and after the treatment) showed little improvement and treatment was subsequently stopped.  Upon further reading into this it seems there are possible problems for long term users of biphosphonates.   This can include the higher risk of fracture after long term use due to the bodies inability to metabolize the drug and the natural effect of the biphosphonate inhibition on the bone cell turnover rate (Ott 2005: 31897).  There are many cases though where drug treatment has proved beneficial; however each case should be merited individually and each person monitored as appropriate.  I will stress here that there are many different types of biphosphonates available and that McCune Albright Syndrome varies in its intensity.

X ray of my left femur and hip with a locking intramedullary rod and screws.  Although please note that two of the femoral neck screws have now been taken out.

Although this is just a short post on the introduction to the disease that is sharing life with me it can also be found in the archaeological record.  Waldron (2009: 214) points out that Fibrous Dysplasia is often best diagnosed in an archaeological skeleton by the noting of either a shepherd’s crook deformity, healed fractures and findings of expansile swellings on one or more bones.  Subjecting the suspected sample to X-ray should show ‘lucent areas with endosteal scalloping and sometimes a thick sclerotic border’  (Waldron 2009: 215).  Unlike today’s vast array of modern medical treatment and surgical procedures, people in the past largely had to make do and mend.

As Roberts & Manchester (2010) discuss in their book, fracture treatment in the medieval age and before was fairly adept at helping in supporting and stabilising the fracture site.  However with repeated breaks in the main weight supporting bones, it is doubtful whether one could have led a normal life if the fractures were not reduced properly or repeatedly after continual breaks (Oakley 2007).  It also should be noted here that due to the nature of McCune Albright Syndrome it is unlikely to be described in the archaeology record as human skin rarely preserves.  It is far more likely that Fibrous Dysplasia is diagnosed based on the skeletal remains.

In the archaeological record Fibrous Dysplasia remains a rare and elusive disease to diagnose, whilst is has actively been described and documented in more recent human remains (Nerlich et al. 1991).  The following two case studies highlight individual cases of where Fibrous Dysplasia has been documented in archaeological material.

A recent case study presented by Craig & Craig (2011) discusses a juvenile skeleton with evidence of polyostotic Fibrous Dysplasia.  The skeletal remains of a child aged 7 years presents with Fibrous Dysplasia with evidence of involvement most noticeable with large bone expansion on the left mandible alongside involvement of the temporal, maxilla, parietal and frontal craniofacial bones.  A review of the burial context of the skeleton and of the Anglo-Saxon cemetery population that the child comes from shows no differentiation between this and other burials, indicating no differentiation in the disposition of this child’s body or associated grave goods.  Craig & Craig (2011) also cite further Ango-Saxon literature to suggest that it is highly unlikely that the child was stigmatized due to his disability, although we can never know for sure.

Recent evidence in a 120,000 year old Neandertal individual from the Upper Pleistocene site of Krapina in present day Croatia highlights the likely evidence for Fibrous Dysplasia presence in a small rib fragment (Monge et al. 2013).  This is extremely rare to find a bone lesion or tumour  in skeletal material from such a period and it is extremely exciting.  The rib was allocated original as a faunal remain when the site was initially excavated, but the rib was recognised for being of Neandertal origin by sharp eyed human osteology legend Tim D. White (Monge et al. 2013).

X ray of the transverse fracture of my right tibia and fibula in the summer of 2009.  This was the first of three transverse fractures of the right tibia and fibula that followed in quick succession over a short number of years, and resulted in the fixation of the tibia with a permanent titanium plate.

Below are some medical and non-medical sources of information on the various aspects of both Fibrous Dysplasia & McCune Albright Syndrome (FD and MAS). This includes a few recent palaeopathology articles that are freely available, medical articles discussing both FD and MAS, core palaeopathology textbooks and support groups in the US and UK for sufferers of the bone disease.  Although the disease is not headline grabbing news, the lack of research into the socio-economic aspects of the disease is distinctly lacking, as is the number of foundations or adult support services for sufferers with the disease.

I am thankful for the support of my friends, family & my consultant in the treatment of this syndrome and for continued support given.

N.B. The origin of the Ilizarov frame is particularly interesting.  It was first used in the 1950s in the USSR, with Dr Gavril Ilizarov originally using bicycle wheel spokes to fixate, support and lengthen badly fractured bones.  It was only introduced to the West in the 1980’s as a direct result of Ilizarov’s corrective surgery on a patient in Italy when all other options had failed in healing the patient’s fractures.  So far I have managed to avoid having the frame but it is still a standard procedure for badly fragmented fractures, in particular it is often used after motorbike accidents or reconstructing limb angulation/length.

Bibliography and Further Sources:

Fibrous Dysplasia:

Medical Articles:

  • Lee, J. S. FItzgibbon, E. J., Chen, Y. R., Kim, H. J., Lustig, L. R., Akintoye, S. O., Collins, M. T. & Kaban, L. B. 2012. Clinical Guidelines for the Management of Craniofacial Fibrous Dysplasia. Orphanet Journal of Rare Disease. 7 (1): 1-19..
  • Marsland, D. & Kapoor, S. 2008. Rheumatology and Orthopaedics. London: Mosby Elsevier.

McCune-Albright Syndrome:

Medical Articles:

Palaeopathology:
  • Aufderheide, A. C. & Rodríguez-Martín. C. 1998. Cambridge: Cambridge University Press. (pg.420-421).
  • 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.
General Medical
  • Pub Med, a US National Library of Medicine website.

Flesh On The Bones

29 Mar

I apologise for not updating in a while.  I have been busy volunteering in York for YAT, whilst also starting to volunteer for a local council in the Cultural Services department (covering museums, collections, art galleries & education outreach).  Over the past few weeks at YAT I have had the chance to get my hands on a few of the skeletal remains, recently dug up from the ongoing Hungate site.  This included the cleaning of two Roman era skulls, of various mixed in femora (thighs) and humerii (upper arm bones), and studying a number of cleaned skulls alongside getting the chance to lay out a human skeleton.

Differences between femur & humerus elements

I am always struck by how gracile the human skeleton is, especially compared the faunal remains often found on archaeological sites.  In the first instance of seeing actual human bones, I’ll never forget remembering how small they seemed.  Of course, as osteoarchaeologists, we have to put the flesh back on the bones so to speak, to help tease out the information contained within the skeleton.  Yet, first we must know what we are dealing with.  The two elements above are quite distinctive in their size and robusticity.

As I cleaned the various bits and bobs of the skulls and bones, it was hard to remember that they came from a society and culture very different to the one I am living in now.  From the northern fringes of the late Roman Empire in the city of Eboracum, these bones had lain mostly undisturbed (apart from some Viking & Medieval action).  They had survived due to good soil preservation whilst the Empire they knew crumbled.  Everything they had once known has since become lost or amalgamated as invaders and settlers, cultures and societies, came and went.   As I cleaned each bone in isolation, in my white laboratory shirt and blue gloved hands, the archaeologists outside where digging through the layers and contexts, unearthing and freeing the remains.  This was a part of the process of archaeology- planning, researching, excavating, finding, documenting, cleaning, labelling, storing then onto investigating and researching.  Each step is vital and may uncover new things. 

When you are holding a persons earthly remains in your hands, its hard not to think what that person may have seen, heard and felt during their lifetime.  How different was this city to them?  Who had they loved?  What conditions did they live in?  What job did they have?  What relationship did they have to the other people found nearby? How and why did they die?

By holding a mandible (lower jawbone) in my hand, seeing the teeth in their sockets, and observing any tooth wear or loss, you can help to start to visualise the person before you.  If you are lucky and you have most of the skeletal elements preserved, you can start to observe sex and age characteristics of the person.  Studying the entire skeleton can highlight the height as well as the rough size of the human before you.  By observing any abnormalities or pathologies present you can start to get a feel for the person in front of the bones.  If you are truly lucky, you may get to study the skeleton within a population, and pick up on familiar traits within a selection.  Indeed, you can start to put flesh back on these bones. 

Lateral Mandible, Note The Muscle Attachment Points

It is the inquisitive nature of the archaeologist in the study of human material remains that they keep asking questions.  This is a very exciting time to be involved with, and interested in, thee study of human remains from archaeological sites.  Sites such as the Towton battle ground, from the War of the Roses in 1461 in England, are being excavated once again to see if there are any further remains of the estimated 28,000 victims of that Palm Sunday battle.  A osteological report on a clutch of the skeletons discovered in 1996 can be found here (carried out by Malin Holst, of York Osteoarchaeology).  The analysis of the remains show the male combatants to be from a wide age range, and a wide social range.  A further selection of the skeletons also show just how vicious and violent some of the wounds were. 

In a later post I will include some of my own research into how human osteology can help answer some of the questions regarding the Mesolithic-Neolithic agricultural change by studying European cultures.

Alongside general posts expect some posts detailing the vertebrae, skull, ribs, pelvic, arm, leg, foot and hand elements.  Specific areas in human osteology such as the use of chemical analysis (radiocarbon dating & stable isotope dietary data), metric and non-metric traits, lab procedures, ethics and palaeopathologies will also be discussed later on.

To end this post, have a beautiful song.