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Skull pillow

Saturday: June 11, 2016

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I’ve returned from Mexico and have many things I’d like to share, but first I wanted to show something I made yesterday that would be of use for fellow bioarchaeologists: a human skull pillow! Details are at my other blog.

skull_pillow

We use them to protect the skull from rolling around on the hard table surface. Skulls can be quite fragile, yet they can provide the best information when analyzing human remains. Under the right conditions, from the skull alone you can determine age at death, sex, ancestry, and possibly even the individual (particularly if you are working under forensic circumstances). Now, of course, we never want just the skull alone, particularly for sexing a skeleton or other special cases, and truthfully we must always be mindful to be population-specific, but either way – we need to protect the remains as best as possible while we have the responsibility of handling them.

I decided to do this since I’ve been asked to help analyze remains next week (yep, I just got back and yet I am leaving town once again – and after that I’ve been invited to an archaeological project near Cahokia!). There never seemed to be enough pillows at the lab there, so I’m donating these.

 

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Class Notes: Human Osteology

Monday: January 9, 2012

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Week 15: Taphonomy

Tuesday:

Since we covered taph the week before, this week was actually centered on case studies and final review. The case studies came directly out of our textbook Human Osteology, so I won’t go into detail here (see the Library page for more information). What we got out of the individual cases was that taphonomy was highly important in a forensic case involving burned bones. The key to bioarchaeology is understanding issues like osteoarthritis at a population level. Only and entire suite of patterns can indicate cannibalism. The oldest known cemetery likely belonged to Homo heidelbergensis, 200,000 years ago (and man oh man, what a crazy complex dig that must be! Google Sima de los Huesos, you shan’t be sorry.)

Thursday:

Dr. S set up more stations, mostly involving paleopathology and taphonomy again. I spent a good portion of class (and later much of the entire day) with the bones I failed the most on: frags of the sphenoid, metatarsals and metacarpals, and long bone shafts.

Friday:

Our skeletal reports were due, and my ex situ commingled stuff was just nearly finished (which was ok since I had already completed the baby). I spent much of the entire day again studying. I was grateful this week that so many undergrads were in the lab. They kept me alive by feeding me with their swipes and entertaining my brain before I got burnt out. Was I ready for the final? No way. Lefts and rights. Rights and lefts. Siding was not my friend, but what more could I do?

Since this post is delayed, I do happen to know my score. It was not what I wanted. It was a high B. What kind of osteologist am I to become?? I was pretty down and out about it. (As my advisor well knows, I think of an A as passing, a B as barely worth it, and a C as failure – this is grad school, yo!) But as all my scores came in, between the tests, quizzes, and skelly projects, I rounded out with an A after all. Phew.

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Class Notes: Human Osteology

Sunday: January 8, 2012

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Week 14: Case Studies

Tuesday:

Fall break was not scheduled into the syllabus so we got an extra week to really go over some bioarchaeological issues. On Tuesday, we learned a new inventorying program that was installed in the lab, called Osteoware. Its purpose is to standardize inventorying so that skeletal databases can work in kind. I do not have much experience with it yet, but I see its potentional. I will be interested to see updates come out though because some segments are a little clunky right now. However, considering they offered it for free and I understand through my husband what it takes to program, I have faith that it really can become *the* database of choice. I am always terrible excited when his field mixes with mine for some reason.

We also covered taphonomy. Taphonomy references the changes which occur after death, including all factors from the biological breakdown to the cultural mortuary practices to the geological processes which affect individuals after death. The importance of understanding taphonomy is so that a researcher can distinguish between natural environmental processes and cultural treatments. Taphonomy is also useful in distinguishing either of these from pathology that the individual may have suffered.

Biological agents include animals (namely rodents and carnivores, but any animal can take part in trampling) and plants. Animal evidence is seen through crushing to access marrow, canine punctures, scalloped gnawing, and breaks by trampling. Plants are attracted to mineral rich soil, and decaying organisms provide this environment. Their evidence is seen through root etching and staining, breaking or obliterating bones, and algae, lichen, moss or fungi growth directly on the bones.

Cultural practices can include the preservation of burial or the thermal alteration of cremation, but also other factors. Burial in coffins can lead to coffin staining and coffin wear. Some cultures cleaned flesh from the skeleton prior to internment and this can be noted with cut marks. Further evidence of cut marks, pot polish, and crushing for marrow can be interpreted as cannibalism. Modern machines can disturb grave sites intensely. There are many other ways that people themselves can partake in the processes of taphonomy, these are but a few.

Non-biological agents are varied. Water can leach bone of minerals, weather the cortex, stain bone dark brown, and transport it. The sun can bleach bone to extremes, cracking and splitting it in diagnostic ways. The pH level of soil can either aid or hinder preservation (bone is best preserved in alkaline soil, while soft tissue is best preserved in acidic bogs). Wind can cause transport, aid in drying bone, or wear with sand grains. Gravity is a great transporter as well.

Thursday:

Taphonomy itself has high inter-observer error – maybe not necessarily in observation rates, but in descriptive remarks. It is also difficult at times to declare whether or not something affected the bone just prior to or just after death. Think of scalping, for instance. It is known that people survived being scalped (healed wounds as evidence), so scalping would occur prior to death, but in some instances scalps were taken after death. Only the latter is considered taphonomic, however.

Another point is that all things aside, two individuals will not preserve the same. Children and the elderly often are the first to return to Mother Earth because their bones are smaller and frailer. Therefore, in a population where much of the individuals are middle adult age, it is important to understand whether this is true due to taphonomic processes, is the population did not reach elderly age and the children were buried elsewhere, or if children and elderly both were buried elsewhere.

Friday:

We held a lab on paleopathology and taphonomy. Dr. S set up many stations so we could practice identification and distinguishing between the two.

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Class Notes: Human Osteology

Saturday: January 7, 2012

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Week 13: Fall Break

Tuesday:

Another lab day since we missed ours from the week before.

Thursday & Friday:

Closed for Thanksgiving!

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Class Notes: Human Osteology

Friday: January 6, 2012

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Week 12: More Paleopathology

Tuesday:

We checked out a bunch of examples from the Fun Box of Paleopatholgy. This included osteomyelitis, misaligned healed fractures, periosteal reactions, osteophytosis, eburnation, enthesopathy, spondylolisis, osteoarthritis, myositis ossificans, cut marks, ankylosis, and ankylosing spondylosis. Yep, it was one of those days that I wondered why I signed up for a field with such huge words to take notes on.

Thursday:

We had a simple lab day to work on our skeletal projects. I don’t recall where I last left off with my posting on this. Originally, I was assigned an infant skelly. Once I finished the baby, I moved on to some commingled remains from our BARFAA project.

Friday:

Friday was a special class because Dr. Wilson from IUPUI came to give us a Transition Analysis lecture/lab. It was the same as the one I sat in during BARFAA but with my class being smaller and more intimate, I felt like I learned more – of course, that may simply be because this was the second time hearing it. Basically, this new method is advocated to be more reliable, replicable, and quantifiable than past methods of scoring data. If I felt qualified enough to delve into detail, I would. Instead, I will cover just the very basic concepts used.

The traditional methods of scoring the auricular surface and pubic symphysis are sometimes called Suchey-Brooks or the Lovejoy methods. Cranial sutures are also scored for aging. Research has shown, however, that these methods tend to provide results which mimic the original reference sample – making the life tables for all kinds of populations look oddly familiar. These methods utilized phases of bone formation and degeneration. Transition analysis introduces using stages instead. Rather than trying to lump all the evidence given by the feature being studied, it measures each variable independently and provides probability statistics based accordingly, unlike the pigeon-hole phenomenon with a phase-based system. The stage system allows for more variability in the measurements because more possible combinations can be recorded (instead of scoring a single general phase for the development of the apex, ventral rampart, surface porosity and whatnot, it allows individual scores for each of these).

Functionally, transition analysis software lets you input each of these individuals independently, then scores the total age range for the given parts in a bell curve for each feature. The program calculated the P value and gives you the most likely age at death. Its best advantage is omitting that 50+ category. The old idea that people in the past didn’t live as long as we do today is not nearly as accurate as the stories tell. It is simply that most of the methods available for calculating age are unable to distinguish ages among older people. Transition analysis, however, can give you much more precise ages, and the P value still allows a check on accuracy. If you ever get a chance to attend a program on transition analysis, I urge you to check it out.

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Class Notes: Human Osteology

Thursday: January 5, 2012

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Week 11: Paleopathology

Tuesday:

The study of ancient skeletal alterations due to processes that are deleterious to health is known as paleopathology. Paleopathologists use differential diagnoses; that is, they list all the possible causes for what is observed on the skeleton, then rule out cases and narrow in on the likely cause. Unlike medical practitioners who rightly treat the individual rather than observing the bigger picture, bioarchaeologists examine the pathological evidence within the scope of the entire population and track the history of diseases. Therefore, the study is epidemiological and correlates human action with disease. That is, do certain cultural traits promote or hinder pathological conditions? The study is limited however: there is no communication between the affected and the examiner as in the medical field; there is no evidence of soft tissue involvement (unless in the rare cases of mummies); and chronic diseases are better understand rather than acute ones, which would have killed the afflicted before the skeleton had time to react in the diagnostic ways.

There are several classifications of paleopathology that can be recorded in a skeleton. These are: arthritic changes; trauma; infections; tumors/neoplasms; and congenital, metabolic, endocrine, and circulatory disorders.

A readily observable pathology is that of arthritis, otherwise known as osteoarthritis or degenerative joint disease. In fact, it is the most common condition found in ancient bones and results from activity-related breakdown of the synovial joints. As the cartilage protecting the joint wears down and disintegrates, the end of one bone will contact the end of another. Bone, being a living tissue, will react first with resorption (seen as pitting), then the bone will expand the joint to disperse the stress (seen as lipping, or extra growth of bone), and followed by eburnation (when the bones physically polish each other to a shiny sheen). Furthermore, some lipping can become extreme and fuse the joint together (ankylosing, or stiffened joint) – a trait seen in toes commonly, I’m told. Typically, this type of reaction is from secondary arthritis, or that cause from a traumatic event. Lipping of the spine has a special classification and is known as osteophytosis (osteoarthritis is a term used strictly for synovial joints; therefore a vertebra may have osteoathritis on the zygopothesis and osteophytosis on the body). Generally, arthritis is age related and the pattern shown on a skeleton can give evidence of activities. For instance, a population with a high percentage of arthritis showing its effect on left shoulder + right knee may mean that percentage of people were doing a similar activity – other clues found through archaeology or history can aid in interpretation. So it has been documented then that agricultural populations tend to show less arthritis than pre-agricultural groups (though not always) and that Eskimos show the highest levels of arthritic changes proving the intensity of their labor in such a harsh environment.

Trauma is the second most common pathology recorded. Patterns found in the fractures of bone indicate terrain topography, occupation activities, violence, and disease. Colle’s fractures (distal end of the radius) are associated with falling (when you throw your arm down to stop yourself) – high percentages likely related to the type of terrain. On the other hand, parry fractures (found on the unla) are associated with self-defense (when you throw your arm up to block something from hitting your head). In that same vein, depressed fractures of the skull often are interpreted for violence but these can also be caused by falling. Pseudoarthritis is also found in the archaeological record – a pathology resulting from a broken bone which never heals together but rather heals apart, creating a false joint. Collapsed vertebrae and vertebral psuedoarthritis are other forms of trauma that is related to disease and will be covered later.The rates of healing and correct versus incorrect alignment are taken into account to interpret medical skill/knowledge/technology of past populations as well.

Speaking of medical knowledge, some populations extensively used trepination and it is thought that they understood this would relieve endocranial pressure. Trepination is when a part of the skull is removed – either through drilling, cutting, or scraping. Fascinatingly, 90% of known trepination cases shows healing which means that the individuals were surviving this type of surgery without modern tools, medicine, or even anesthesia!

Thursday:

Some pathology can share resemblance with osteoathritis. The first is Diffuse Idiopathic Skeletal Hyperostosis, or DISH for short. It’s cause is still unknown and tends to occur in older male adults (those beyond 50 years). It involved fusion of four or more consecutive vertebral bodies, but does not affect the zygopotheses or the cortovertebral joints, nor does it affect the sacroilliac joint. It also preserves the intervertebral space (between each vertebral body). DISH involve excessive bone growth along the anterior longitudinal ligament – so much boney growth that it has been likened to a melted candle stick.

Ankylosing spondylitis is similar but note the differences. It affects almost only males who are young (under 40 and as early as childhood). It effects all parts of the vertebrae and can create fusion with the sacroilliac joint. The annulus fibrous between each vertabrae ossifies, syndesmophytes grow (similar to osteophytes) and complications can make this disease fatal.

Sometimes confused with gout, rheumatoid arthritis is different than osteoarthritis because instead of being related to age and activity, it is an autoimmune disease. Found mostly in females, it affects the hands and knees most commonly. Because it is inflammatory in nature, it causes osteoporosity and cyst formation. It can also lead to ankylosing of a joint.

Gout, on the other hand, is caused by the buildup of uric acid and typically is found in people over 40 years old. Sodium urate crystals can inflame the bone and cartilage. Because it also affects the hands (and commonly the feet), it can be mistaken for rheumatoid arthritis. However, the pitting created by gout can be huge – up to an entire centimeter whereas rheumatoid arthritic pitting is typically only a few millimeters in diameter.

Infection conditions are caused by an external pathogen, which is almost always microbial (parasitic infections from worms is another form). Viruses, bacteria, and fungi can all infect an individual, wreaking havoc on the body and leaving scars on the skeleton. The most easily recognized infections are caused by bacteria though. Periostitis and osteitis are terms used for when there has been evident periosteal reaction to something, but that something is too vague to diagnose (in fact, it may not have been caused by an infection at all).

One of the most prevalent bacterial infections recorded in bioarchaeology is that of tuberculosis. TB has been impacting human lives for thousands of years – dating back 2000 in India, 5000 in Egypt, and up to 9000 in Europe. Contrary to popular belief, it did exist in the Americas before “contact”, although it was rare. Caused by Mycrobacterium tuberculosis, this pulmonary disease (involving the soft tissue of the lungs) will eventually spread to the inside surface of the ribcage and the spine in chronic conditions. Thoracic vertebrae can show smooth walled pitting, which leads to collapse. If TB progresses this far and the verts show this characteristic wedging, it is known as Pott’s disease. TB often causes changes within the midface as well, resorbing the bones around the nasal aperture and sinuses; it can also affect the knees and hips. TB proves an important case for considering the osteological paradox: for TB to be seen on the skeleton, the individual must have lived a long time with the illness in a chronic state. Therefore, when the skeleton is studied, how should that individual’s health be considered? Surely being able to survive the disease long enough to have skeletal changes means your body was more robust against it than the person who died quickly before these changes occurred, leaving a healthy looking skeleton. But alas, there is no way to know if that healthy looking skeleton belonged to an individual who even ever had TB to begin, so perhaps that person may have indeed been healthier. Or perhaps they did both have it, but they suffered from different strains of M. tuberculosis with different virulences. At this point, with DNA studies few and far between due to preservation and resources, who can say. The osteological paradox just needs to keep a researcher on their toes and not leap to interpretations.

Moving on, another common infection found in the bioarchaeological record is that of osteomyelitis.It is a favorite for researchers because the bacteria acts upon the human body today just as it did in the past so it is easily diagnosed in skeletons. It is cause by Staphylococcus aureus bacterium – aka the well known Staph infection. In fact, in recent times there has been a renewed interest in public media due to its drug-resistant form, MRSA (Methicillin-resistant or multidrug-resistant S. aureus). The bacteria on the skin spreads to the bone in the local area of infection due to a build up of pus formation. This can cause a resorptive reaction of the bone, creating lytic lesions. In fact, the bone often reacts so intensely that it literally tries to cut out the infection. Bone resorbs around the infection, boring a hole (termed cloaca) through to the medullary cavity, thus leaving an island of affected bone in the center (the sequestra) . The healthy bone reacts by building up around the hole, forming what is known as an involucrum.

Yikes, right?

Friday:

Another infectious disease common to the archaeological record is  treponemal disease. It has two forms: syphilis (a sexually transmitted disease) and congenital (mother-child at birth). This too has been rumored to not have existed until the time of “contact” but archaeology has proven this not to be the case. Because the illness is slow, it is a chronic condition which leaves evidence on the body in the same manner as TB. Tibias will show a pronounced apposition of bones along the anterior crest, giving the saber shin appearance. This differs from that of rickets- the bones do not bend, but merely appear so. A skull will show lytic lesions in a diagnostic stellate shape, which sometimes progresses into pitting with bump formations, known as caries sicca. If a child contracts the disease during gestation or at birth, it can affect tooth formation. This results in characteristic Hutchinson’s incisors (notched edge) and mulberry molars (where the cusps are poorly developed).

Metabolic diseases are also recognized in past populations. For instance, a vitamin D deficiency can lead to rickets in children, or osteomalacia if extended into adulthood. A lack of vitamin D disrupts the roles of calcium and phosphorus in the body, which means that the rigidity of bone is lessened. Particularly in weight bearing long bones, this causes bones to bend, giving the characteristic bowed leg effect. It is common in people with terribly poor diets, and also in areas with low sunlight, as the sun triggers skin to produce the vitamin. Interestingly, low sunlight is not just an effect of where you are in the world (less light further from the equator, and the problem is exaggerated with darker skin colors), but also the culture. Industrializing cities with long days spent in factories, or religious communities that prefer clothing that covers much of the skin can both be causal factors for rickets and osteomalacia.

Porotic hyperostosis and cribra orbitalia are two other commonly found metabolic diseases, involving what is thought to be a response to low iron levels. PH affects the outer table of the crania, resorbing until the diploe is exposed, giving a “hair-on-end” appearance. CO, on the other hand, affects the orbital roof, sometimes growing spicules.Both are non-specific; that is the cause is unknown. Are the iron levels low due to a poor diet, a parasitic infection, a congenital susceptibility, a protection from worse symptoms, all or none of these? What is known, however, is that they are diseases of childhood. This is because the role of bone in blood production lessons with age and therefore both PH and CO are typically scored as healing/healed in adults.

Briefly covered were some congenital disorders. Pituitary gigantism results from a tumor of the pituitary gland. Because it begins in children prior to fusion of all the epishyses, the body will grow porpotionatly. Also affected is the shape of the sella turcica, or the boney saddle that the gland sits in, which will be enlarged and diagnosable. In addition, gigantism is hard to miss – in the archaeological record, people have been found to have grown 8 feet tall. A more common form of gigantism is that of acromegaly. Because of its later onset, fusion has already been taking place. This leads to only some bones allowed the extra growth: the mandible, clavicle, ribs, etc. You can recognize this form on “smaller giants”, with big chins, wide shoulders, and heavy brows. The opposite of these is achondroplastic dwarfism. It occurs when the growth plates do not form correctly, causing early fusion. It only affects endochondral bones, which is why people affected with this disorder will have a normal size torso and head, but shortened limbs.

And to round things out, a few mischellaneous bits. Myostitis ossificans is a mineralization of tendons at the muscle attachment point. It can form as a result of trauma, which need not be particularly detrimental, or it can from as a result of a congenital disorder which can be more severe, limiting movement and such. A button osteoma is a benign bone tumor. It is fairly common – you may know someone who has one. It is simply a small button-like growth on the skull. Feel around your own head, maybe you even have one yourself!

 

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Class Notes: Human Osteology

Wednesday: January 4, 2012

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Week 10: Review & Exam

Tuesday:

Although this week was meant to be used for review and an exam, we instead covered more class notes. In bioarchaeology, there are three main classifications of ancestry. It is critical that you understand what is meant by “ancestry”. Anthropology has come a long way since its inception yet unfortunately many people still believe we speak about differing “races”. Ancestry removes the cultural construct of the concept of race (since physically race does not exist), thereby limiting its definition to the physical form. In bioarchaeological terms, ancestry relates to the geographic location of someone’s ancestors – and until worldwide travel became so efficient, there were three basic groups: those from Africa, from Asia, and from Europe. It also is important to note that there is no “norm” because variation is the norm. As such, those between the two centers of ancestry will show overlapping traits. I will list some traits commonly used for identification, but it is crucial that a suite of traits is used for identification rather than any single marker and it must be understood that most traits lie on a scale rather than a simply being present/not present. Also understand there are a lot more traits to use but I kept the list brief for a simple overview and comparison.

African ancestry: Wider nasal aperture with rounded nasal bones and a guttered margin; alveolar prognathism and a midline diastema common; hyperbolic dental arcade; large molars with cusps 5, 6, and 7; blunt chin and straight mandible edge.

Asian ancestry: Tented nasal bones with a broken gutter nasal sill; prominent zygomatic (cheek) bones giving face a broad appearance; wide angled dental arcade with incisal shoveling common; broad and projecting chin and rocker mandible

European ancestry: Steepled nasal bones with a deep nasal root and a sharp nasal sill; overjet and overbite common; small molars and Carabelli’s cusp common; v-shaped dental arcade; bilobate chin and undulating mandible

Thursday:

 We were allowed lab time to study for our exam. Nothing too exciting to write about.

Friday:

Exam numero 2! It was only a practical (no written part) and the class as a whole did not meet expectations. I was among them myself with a crummy grade. In fact, this was when I first realized that I wasn’t getting it, but I did not understand why and therefore did not know what to do. I met with my teacher and he was surprised (not having known my grade yet since the assistant was the one to go over the test with us and apparently I was one of the better students). He felt his advice was weak since it wasn’t like I was fubbing up on any particular type of problem (my mistakes were all over the board: lefts & rights; identification; sexing; aging; ancestry), but truly it made since: If you think you know what a fragment is, think about everything else that will give evidence to support your hypothesis. I worked hard with this for the rest of the semester.

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Funny Story

Wednesday: November 9, 2011

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It is apparent that I am a non-traditional student. 30 year olds can only pass for just-out-of-high-school college kids in bad movies. I am ok with that: I bring a lot of life wisdom and experience with me but it is certainly awesome when I surprise people with my age. Several of my undergrads were (are?) in denial.

The other older grad student, Andy, called me out on it. Being non-traditional himself, he had to know my age. He guessed first and filled me with cheer at the ripe young age of 26. [Most of the undergrads put me at 25 or less.]

That being said, my geoarchaeology teacher is young, and I had determined he was young enough to be my brother. One day, while having class outside working with the total station, I heard Andy refer to our teacher’s birth year. Imagine my surprise when it was made known to me that we were born in the same year.

I only let a few minutes pass before I had the nerve to ask. I mean, egads, what if I was OLDER than my teacher, right? Right?! I had to know.

“So, when is your birthday anyway?” I asked nonchalantly.

“August 11” came the reply.

Needless to say I was stunned and calmy replied “Really? That’s mine…”

So, ok, I may not be older than my teacher (dare I ask if he was born in the morning or evening??), but it has been something, I tell you, getting my head to wrap around the idea that I am as old as my teacher. I am totally use to people with grey or greying hair, or at the very least, born in a different decade for Pete’s sake.

Brightside: He is the first person I’ve ever met who shares my birthday. In celebration, here is a sketch I whipped out for osteo class way back when I still felt young.

Sketch of a skull

Human skull sketch for a Human Osteology lab worksheet identifying synapsids.

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Class Notes: Human Osteology

Wednesday: November 2, 2011

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Week 9: Age, Ancestry & Sex

Tuesday:

For class purposes, we have defined Young Adult to be 18-35, Middle Adult to be 35-50, and Old Adult to be over 50. For sub-adults, dental formation is key to aging, but for adults all teeth have been erupted so other methods are needed. Aging adults in bioarchaeology is really more about serial relationships among the population than true chronological age of individuals. One of the ways a skeleton can be aged at time of death is by examining the pubic symphysis. As mentioned in an earlier post, this area will experience a break down over time. The 1920’s model by Todd was the first, with 10 stages denoted by qualitative descriptions. In 1990, Suchey and Brooks developed another method similar to Todd’s but with only 6 stages and that also divides between males and females.

A second method of scoring skeletal age at death is through Lovejoy’s examination of the auricular surface. This is the ear-shaped surface created by the joint between the sacrum and the ilium.

A third method is identifying suture closure status of the cranium. Looking at standard points along the suture lines and scoring between open through obliterated can help identify age.

Thursday:

We used the above methods for our skeletal projects. Then we discussed how to sex a skeleton. Obviously without the fleshy bits, this is easier said than done. However, our species like most does incorporate a certain amount of sexual dimorphism in general. Not always true, men tend to be about 5-10% larger than females in both length and robusticity. This includes metric and non-metric traits alike. The best place to find sex indicators is the pelvis, although the skull can also have good evidence.

Friday:

We went into further detail over sexing a skeleton. Males tend to have a larger malar region and larger canines. Their jaws tend to be more vertical and have a wider ramus, while also showing a wider and larger chin. Females tend to have a gonial inversion of their mandibles. In the pelvic area, several indicators are present. These include the symphysis shape, pubic length, shape of obturator, ventral arc, medial aspect ridge, subpubic angle, greater sciatic notch, preauricular sulcus, elevated auricular surface, ischial tuberosity, shape of auricular surface, subpubic concavity, sacrum curl, and size of alae.

It is important to note that these features are not accurate 100% of the time. The dichotomy of sex must be understood as two bell curves with an overlap between them. Indeed, there are effeminate men and masculine women in all cultures and through all time. Young men also will have more slender characteristics than their older counterparts. Older women, after menopause, will start to show masculine traits of their skeleton. Therefore, many different variables need to be scored together to identify sex, and this is often why sometimes you will see “indeterminate sex” because it is a toss up between male and female indicators or not enough indicators were preserved for a confident classification.

 

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Class Notes: Human Osteology

Tuesday: November 1, 2011

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Week 8: Skeletal Project

Tuesday:

Fall break, woot!

Thursday:

We discussed morphometrics, which is the relationship between measurements and shape. We also covered the biological profile of age and sex. Age shows a growth threshold, involving both intrinsic developmental factors and extrinsic degeneration factors. Developmental aging includes tooth formation, epiphyseal fusion, bone length, and suture closures. Degenerative aging includes joint morphology, auricular surface appearance, and pubic symphysis break down.

Friday:

Osteometrics lab and more inventorying. I finished the little one and began an adult with some interesting pathology but my focus was asked to be shifted back to the BARFAA group now that my assignment had been finished (the adult would have been just as extra).

 

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Class Notes: Human Osteology

Tuesday: November 1, 2011

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Week 7: Osteometrics & Craniometrics

Tuesday:

We ran through some siding techniques for the small carpals and tarsals. Laura added with her “laurisms” and Amber had one of her own too. I’ve also made a few of mine. Here is a breakdown:

Carpals:

Scaphoid: Look at the side that resembles a snail (the convext suface). It crawls to the side its from.

Lunate: Hold it with your thumb in the groove and the box-like projection is on the side its from.

Triquetral: Hold the pinchy facet (the facet that wraps around the corner) and the circle facet at the top will be on the side its from.

Trapezium: Hold it like a cross and the groove will be on the side its from.

Trapezoid: Look at the zippered boot, and the toe points to the side it is from.

Capitate: Look at the flat side and imagine it to be a bust. The flowing hair hangs down on the side its from.

Hamate: Look directly at the pinchy facet and the hammer will be on the side its from.

Pisiform: This bone is not typically worth siding, and techniques do not always work correctly.

Tarsals:

Calcaneous: Hold like a wii remote, and the comfortable hand is the side its from.

Talus: Hold with the ball in your palm and your thumb in the concave facet. The comfortable hand is the side its from.

Navicular: Hold with your thumb in the concave facet and the point under your index finger. It will point to the side its from.

Cuboid: Look at the dinosaur head, and it wants to eat the side its from.

1st Cuneiform: Hold with your thumb on the kidney bean facet, with the L-shaped facet facing you. It is on the side its from.

2nd Cuneiform: Look at the flat non-articular surface as if it is a house. The slanted roof points to the side its from.

3rd Cuneiform: Look at the concave facet with its point down. The more dipped side is on the side its from.

Class discussion then went over how to measure bones using sliding calipers, spreading calipers, an osteometric board, and a measuring tape. Then we began measuring our skeletal projects.

Thursday:

We walked through Fordisc, a discriminant function analysis program which calculates ancestry relationships using a suite of metric data. Today was another lab day for our skeletal project.

Friday:

Quiz and more lab, as usual. No organized discussion, just a lot of inventorying and measuring.

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Class Notes: Human Osteology

Tuesday: November 1, 2011

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Week 6: Hands and Feet

Tuesday:

Since we had already covered this week’s topic, we moved ahead to receive our assigned skeleton. We discussed the procedure for inventory and the different paperwork that is used by the lab. As I had mentioned, I requested a juvenile to push my limits and the baby was very tiny. I was able to correct classification the archeologists had made, and find one of the tiniest human bones: an ear ossicle (the malleus to be precise).

Thursday:

I do not recall exactly, but due to my lack of notes for this day I imagine we had lab time during class to work on our skeletal inventories.

Friday:

My cohort and I worked on our BARFAA presentation during class time with Dr. S while the undergrads had lab with Laura. We put the final touches on a keynote presentation and walked through it a few times before practicing in front of the class. I had this annoying habit of saying “Upper” Woodland (instead of “Late” Woodland) because my undergrad focus was mostly human evolution and therefore “Upper” Paleolithic and such. This might seem a small detail, but I assure you it is not a mistake I would want to make in front of an anthropologically educated audience!

Cute shoes

Grad school feet in grad school grass.

This was a rough week for me, having BARFAA coming up and the other graduate duties and classwork. I won’t lie, I was pretty stressed and have basically been behind in coursework since. I think the experience was great so no regrets there, but trying to balance it with school work and a weekend husband was not the easiest thing at the beginning of my first semester after a 2.5 year break. Lucky for me, my grades do not reflect the hardship. I hope that stays true for the rest of the semester!

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Class Notes: Human Osteology

Tuesday: November 1, 2011

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Week 5: Shoulder and Arms

Tuesday:

The shoulder girdle connects the forelimbs (appendicular skeleton) to the thorax (axial skeleton). It is a very shallow ball and socket joint, allowing for great flexibility. The forelimb design is a common tetrapod design. The proximal half contains a single bone, while the distal end is made of two bones, terminating in the hand, which contains carpals, metacarpals, and free moving phalanges.

The shoulder girdle:

  • Scapula
  • Clavicle

The forelimb:

  • Humerus
  • Ulna
  • Radius
  • Carpals
    • Trapezium
    • Scaphoid
    • Lunate
    • Pisiform
    • Triquetral
    • Hamate
    • Capitate
    • Trapezoid
  • Metacarpals 1-5
  • Manual Phalanges
    • Proximal
    • Intermediate
    • Distal

We learned the various features of each bone and how to side them. Interestingly, I have spent a lot of time on the small bones of the hand which now I find easy, but I am having trouble with the larger bones of the arm. I wonder if this is normal. Remember, we do not get tested over full bones. Fragments are what is found in the archaeological record so fragments I must know.

Thursday:

We jumped ahead to the pelvis and lower limb. The pelvis is a paired group of three bones: the illium (what you feel as your “hip bone”), the ischium (what you sit on), and the pubis (which can be felt in the nether regions). These two sets of bones fuse early on to become two oddly shaped bones, sometimes referred to as the ox coxae or the innominate. The leg is in the same model as the arm: a single bone in the proximal half, two bones in the lower half, terminating into tarsals, metatarsals, and phalanges. My favorite bone pops in at the knee: the patella.

The lower limb:

  • Femur
  • Patella
  • Tibia
  • Fibula

Friday:

  • Tarsals
    • Calcaneous
    • Talus
    • Navicular
    • Cuboid
    • 1st Cuneiform
    • 2nd Cuneiform
    • 3rd Cuneiform
  • Pedal Phalanges
    • Proximal
    • Intermediate
    • Distal

Just like the upper bones, I am pretty confident in the small bits, but the long bones trick me often. I am decent at identifying which bone it is, but siding is still a struggle. I missed the practical lab section here because I was working with my cohort on a presentation for BARFAA coming up on the 8th of October. This is part of my problem with long bones I think, but I should make up for it this week with extra study time.

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School Bits

Friday: October 14, 2011

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Although I have several segments of class notes to type up, I thought I would make a short post about other things happening in grad school.

Over the weekend, my cohort and I presented our findings at BARFAA (see the abstract located here). UIndy was given the responsibility of profiling (at least) three individuals accidentally discovered in Tippecanoe County. Originally, I was to present my own research on teeth from Isreal using the WLCP, but instead we all felt it would benefit the project if I changed course and added dental texture analysis to the accidental discovery. We put together a keynote presentation and though quite nervous, I felt we did well. I was surprised to find that I was able to master my voice and talk slowly during my segment. We had some questions afterward, and I was able to meet several people in the field. Boy came with me so we could make it a mini-vacation, and the next day we attended the workshop for Transition Analysis, by Dr. Wilson of IUPUI. It is a software developed for use by anthropologists. My take is that it is similar to Fordisc, only targeting age rather than ancestry. It allows you to input several measurements and use a range of measurements. Then it will calculate the confidence level and show you a graph which outlines the individual methods and the correlated age from them. I look forward to using the program in my studies.

Since I made a plug for it, I shall make a plug for another anthropologically awesome program. Anthropomotron is designed for estimates of sex, stature, body mass, skeletal population estimates, and various skeletal indices. I am also interested to see how this works out for me.

Aside from BARFAA, I have been working on my Human Osteology skeletal project. I requested a juvenile since I had worked with mostly adults in Peru, and received a tiny baby. It is sad to think he or she passed away so early and the heartache that must have caused the family. Perhaps that thought is ethnocentric, I do not know, but I feel honored to take the little one in my care. From my research this far, I am almost certain the baby did not reach full term. The teeny tininess has proven a learning experience for me – not just because the bones are not at their mature form, but also because they are literally so small, it is simply hard to examine them. I have also learned first hand about the difficulties archaeologists face when excavating children (this site is a CRM recovery, of course). The archaeologists did very well bagging different bones and labeling the bags, but they did not always correctly identify something. A turtle shell was mistaken for a cranial fragment, and some fragments of ribs were misplaced in the fibula and vert bags. The pubes were both placed in the vert bag as well. This avenue is something I would like to explore more – archaeologists do not always get proper osteological training, and even then sometimes children are not discussed in depth. This is for several reasons of course (and will be explained in a later post), but the need is there. Considering the importance of reburial, the most respectful thing would be to collect the whole individual, you know? Tooth buds, epiphyses, and all.

Another cool thing that happened (and then didn’t) is that the DNR called to see if we could excavate a skeleton discovered in someone’s backyard. To have the excavation experience ourselves would have been wonderful but unfortunately it coincided with BARFAA so we could not get there as early as the police requested and they were able to hire someone else. Maybe next time.

Undergrads (friends and strangers alike!) may surprise you with free food since their tuition includes a meal plan that they do not always use. I’ve had this happen twice and it is quite awesome. The anthro undergrads are pretty cool, especially. For instance, today we discussed the anthropology behind zombies. Does it get any more real than that?

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Class Notes: Human Osteology

Friday: September 30, 2011

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Week 4: Spine and Thorax & Review

Tuesday:

 The human body has 24 vertebrae:

  • 7 cervical
  • 12 thoracic
  • 5 lumbar
There are two kinds of curves that create the “S-curve”: lordosis (a ventral curve, employed by  the cervical verts and the lumbar verts) and kyphosis (a dorsal curve, employed by the thoracic verts and sacrum).
Some vertebrae have special identifying features:
  • C1, otherwise known as Atlas, articulates with the skull, allowing us to shake our heads “yes”
  • C2, otherwise known as Axis, articulates specially with C1 via the Odontoid, allowing us to shake our heads “no”
  • C7 is the bump you can feel at the bottom of your neck, and it transitions into the thoracic vertebrae
  • T1 is also transitional between cervical and thoracic, but unlike the cervical verts, all other verts lack transverse foramina
  • T10-T12 transition into lumbar verts, but each still maintains a costal facet which articulates with a rib
  • L5 is transitional to the sacrum (sometimes it even becomes fused with the sacrum)
We also covered the sacrum and coccyx which are each important for muscle attachment. Between each vertebra is an intervertebral disk. This is made of annulus fibrosis, which surrounds the nucleus pulposis, a remnant of the notochord. When a person has a slipped disk, the disk itself does not slip, but the nucleus pulposis is no longer centered. It is estimated that this soft tissue accounts for almost 25% of our vertebral height.

We have twelve pairs of ribs, men and women alike. The first six are sometimes called “true ribs” because they each have a cartilaginous connection to the sternum. Ribs 7 through 10 are sometimes referred to “false ribs” because their cartilaginous connection is shared between them. Ribs 11 and 12 are “floating ribs” because they lack this connection to the sternum.

A sternum has three parts, though these often fuse. The top is called a manubrium. If you have ever seen the movie The English Patient, he referred to the supersternal notch, which is the area we call a jugular notch, between the clavicular notches. The body of the sternum is sometimes referred to as the corpus sterni, or sternabrae. The bottom tip of it is the xiphoid process.

Thursday:

 We had lab time to study for our test. Anna and I spent the entire evening there (much like Tuesday) to go over fragments. I have trouble siding the sphenoid. That bone is not my friend.

Friday:

We had the first test of the semester. 50 written questions, but an additional essay and diagram for the grad students. Then we had 50 practical questions, plus 10 extra hard grad student questions, and an optional 10 question quiz. I got done with both parts early and with time to go over each question to be absolutely sure. There were a few I couldn’t be confident about but overall I think I did alright. My main issue is still balancing time. Two classes demand a lot of time for reading. This class demands a lot of extra lab time. And then I have the Dental Microwear Project to work on also, not to mention commuting and saving time for “weekend husband”. As the semester draws on, I am finally getting the feeling of caught up, so by the end of the semester, I ought to be rocking it.

 

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Class Notes: Human Osteology

Sunday: September 25, 2011

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Week 3: Osteometric Landmarks & Teeth

Tuesday:

In class, we covered the view of the interior cranium, the maxilla, and the mandible. We also covered some common craniometric landmarks used to identify ancestry. Since I have these memorized well: gnathion, incision, prosthion, nasospinale, nasion, glabella, bregma, vertex, obelion, lambda, opisthocranion, inion, opisthion, basion, gonion, ectomolare, ectoconchion, dacryon, zygion, porion, euryon, and pterion.

There are 20 deciduous teeth and 32 adult teeth in most instances. I only had 31 teeth because one of my third molars never developed. Cool, huh? Teeth are made of enamel (which is almost entirely protein and is acellular, which means they will never heal), dentin (which is about 75% mineral but is cellular although not well enough to patch cavities), and cement (about 65% mineral, like bone, and is what Sharpey’s Fibers hang on to inside the gomphosis joint).

The human dental formula is 2:1:2:3. This means that for each quadrant of your mouth, you have two incisors, then a canine, then two premolars, followed by three molars. We were briefly taught how to determine each category, and upper versus lower dentition (except for canines). More specific detail of this will be taught in Dental Anthropology next semester.

  • Upper incisors: Crown will be flat, enamel flares out from root, the root is more round, and wear will be linear.
  • Lower incisors: Crown will be flat, enamel continues evenly from root, the root is oblong, and wear will be linear.
  • Canines: Crown will be pointed, and wear will have a central bulge.

Thursday:

  • Upper premolars: Crown will be a rounded rectangle, and evenly cut in half.
  • Lower premolars: Crown will mostly circular and will have two dimples.
  • Upper molars: Crown will be shaped like parallelograms, and generally only have four cusps and three roots.
  • Lower molars: Crown will be more squared, have a Y5 or +4 pattern, and only have two roots.

As a grad student, I also have to be able to determine first, second, and third molars. Third molars are fun because typically the cusps are all messed up and the roots are tiny. First are generally the perfect examples of a molar, and seconds are intermediate between the two.

Friday:

We were given details on our dental topography project. The machine we will be using is part of my Research Associate position. Not only will I scan the teeth for texture with the white light confocal microscope, but I will also profile them in the topography machine (TopoM). This process takes literally about 2 hours to do a single tooth but it builds a three dimensional view of the tooth.

For lab, we went over more skull fragments and began sorting teeth.

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Class Notes: Human Osteology

Saturday: September 24, 2011

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Week 2: Bone Growth and Joints & Skull

Tuesday:

Bone development (osteogenesis) in the embryonic stage basically forms three layers: the ectoderm, which transforms into skin and teeth enamel; the mesoderm, which forms connective tissues and bone; and the endoderm, which turn into the organs. Mesenchyme in the mesoderm layer will begin to form a cartilaginous skeleton, known as an anlage. This will be followed by a layer of protein matrix which will build the bone shapes. This pre-bone matrix is an osteoid. Mineralization then takes place, creating immature bone. This turns into mature bone once the minerals and proteins become organized through the work of osteoblasts (bone forming cells) and osteoclasts (bone removal cells), to form osteons (organized bone matrix).

Bone repair works in much the same way, beginning with osteoids. If the periosteum becomes strained or torn (the layer on the outside of living bone), a fracture callus will form along with a hematoma (blood mass), allowing osteoids to patch the area until osteoblasts and osteoclasts begin the true remodeling.

There are three classifications of joints:

  • Synarthrosis (fibrous): allows almost no movement (such as that found in cranial sutures)
  • Amphiarthrosis (cartilaginous): allows limited movement (such as that found in gomphosis, which keeps teeth in place)
  • Diarthrosis (synovial): allows much movement (found in synovial joints, which are the typical joints)

Synovial joints come in several forms: ball and socket (ex. hip), hinge (ex. elbow), pivot (ex. shaking head to say “no”), gliding (ex. wrist movement), condyloid (ex. finger joints), and saddle (ex. thumb joint). A synovial joint includes the bones involved, which have a layer of articular cartilage on each of their articular surfaces. This cartilage, along with a synovial membrane, forms the joint, which is filled with synovial fluid. The joint is covered by a fibrous capsule and ligaments keep the capsule in place.

Thursday:

 The first skull appears about 500mya in fish, although it was more osteodentin than true bone. There were no moveable parts, and it acted as armor to protect the notochord. Placoderms derived from this and were the first jawed fish. Chondrichthyes began having a cartilaginous skeleton in addition to the skull plate. Osteichthyes developed a skin covering over the plate, and the plate covered the head, leaving the orbits, nasal, and mouth free. Early tetrapods began the mineralization of the cartilaginous skeleton, and moved out of the water. Their skulls now housed a full brain and teeth.

Today, we see three common types of skulls: anapsids have the boney plate still, but underneath is another boney portion protecting their brain. This set up is heavy, so it works best in aquatic or slow moving animals such as a turtle. Diapsids are similar, except that their boney plate opened up windows to lighten the load. They can move faster on land, and this is seen in alligators. Synapsids opened the window so much that there truly is no longer a window. Instead, synapsids skull is almost entirely only the inner boney portion found in anapsids and diapsids. In fact, the only skull plate left in a synapsid skull is the zygomatic arch (cheek bone). Humans are synapsids.

There are 29 bones in an average human adult skull, along with 32 teeth. In class, we covered the frontal bone, both parietal bones, both temporal bones, the occipital bone, the sphenoid, and the ethmoid.

Friday:

In lab, we examined skull bones to be able to identify features and side fragments.

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Class Notes: Human Osteology

Saturday: September 10, 2011

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Week 1: What is Bone? & Histology & Introductory Terminology

The course objectives are to give students the abilities of:

  • Know every single bone in the human body
  • Know the function of every bone
  • Understand the microscopic anatomy of bone
  • Determine biological profile of a human skeleton
  • Understand how paleopathology, dietary reconstruction, and paleodemography shed light on early human lifeways
  • Complete the analysis of a human skeleton

Books assigned for class are: Human Osteology and Standards for Data Collection from Human Skeletal Remains. Recommended is also: Identification of Pathological Conditions in Human Skeletal Remains. (See the Library page for bibliographic information.)

There are nine students (6 undergrads and 3 grads). The separation lies in that graduates are expected to not only identify a bone but side it, sex and age it when possible, and note any pathology. Instead of being teamed up to work on the skeletal project, we will do it independently. And we must get at least 70% on each quiz in order to pass.

Tuesday:

The skeleton functions to provide support for the body, anchors for movement of muscles, and protections of organs. It also makes blood, stores minerals, and assists with breathing, digestion, the immune system, and the central nervous system.

Briefly, bones are composed of roughly 65% calcium phosphate mineral (part of the hydroxyapatite composition), which gives bones their strength. The other part of the make-up is collagen, which gives bone enough elasticity to not be brittle. We went into detail of long bones, which have three main parts: the diaphysis (the long shaft), the metaphysis (widening of the shaft at either end), and the epiphysis (the end cap which forms separately and fuses during growth).

The diaphysis is made up of dense cortical bone, which then fades into thin subchondral bone (which is covered by cartilage) at the metaphysis and covers the epiphysis. The ends of long bones have trabecular bone, otherwise known as spongy bone. This is so that a bone can absorb impact without shattering. The outside of a bone is covered with a living tissue called periosteum, while the inside of the bone along the medullary cavity (which is where marrow is stored) is lined with endosteum. Because a bone must grow and also remodel after trauma, it needs nourishment like any other part of the body. Therefore, between the marrow (which houses fat and calcium as well as creates blood cells) and the periosteum,the cortical bone is made of osteons.

Osteons are small tubes of lamellar bone which form concentric circles around a Haversian canal. Through the canal, blood, lymph, and nerve endings are channeled. Between osteons are Volkamm’s canals which further channel the means necessary for nourishment. Within the lamellae are lacunae, or small cavities where the actual living cells of bone (osteocytes) needing the nourishment are housed. These are then connected to the entire system via tiny channels called canaliculi.

Thursday:

We went into further detail of the histology of bone and teeth but I will spare you the details (you can check it out at Wiki). Then we covered the anatomical position and its reference planes/directional terms. These include midsagittal, parasagittal, transverse, coronal, and oblique planes. Also, anterior/posterior, ventral/dorsal, superior/inferior, and medial/lateral directions.

Particular kinds of bone landmarks were also mentioned. The list is long but a few of them are foramina (holes), sutures (the squiggly lines on a skull), condyles (where two bones articulate), and fontanelle (the soft spots on a newborns head).

Friday:

Fridays are lab days. They begin with a quiz and the rest of the time is spent working on a packet of material. We covered what I have already mentioned in detail and we had to be able to draw certain items (like an osteon or the parts of a long bone) and label features on a bone (like a protuberance, a turbercle, and a tuberosity). The three hours scheduled truly is not enough time to really grasp it all. It is a little daunting to know how much harder the course will become and how much less free time I will have to hit the lab after hours, but I am excited for the challenge that Human Osteology will give me. Bring it!

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