Introduction to Physical Anthropology

by Arnie Schoenberg
version: 3/X/20

human skeleton with names of major bones

Figure 3.5 human female skeleton, red lines point to individual bones, blue lines point to groups of bones by Mariana Ruiz Villarreal, 2007 (Public Domain)

Section 3 Contents

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3    osteology


3      osteology

Osteology is the study of bones. Osteology is important to studying human variation, and primatology. Paleoanthropology relies on osteology because most fossils come from bones. Forensic anthropology uses osteology to solve crimes.

Like most other physical traits, the bones we see are a consequence of genes and environment. There is nothing particularly profound about bones compared to other biological systems, but their durability makes them special for anthropology because they are the main source of data for paleoanthropologists, important to archaeology, and before DNA testing, they were important to the study of human variation.

We tend to think of bones as dead, dry, and brittle, and when you leave them out in the sun for a few years they do get old. Their hardness comes from a calcium-based crystal structure. The molecules interconnect like columns of Lego blocks.

molecular model with columnar calcium, screw axis calcium, phosphorus, and oxygen

Figure 3.1 Hydroxyapatite molecule, by J. Kirkham © 2007

In a biology class you tend to think of a bone as a living organ, like your heart or your lungs, but in anthropology we are used to looking at dead bones, outside of the body, when they are just shells of the functions they had when they supported living organisms.

diagram of bone growth beginging with the hyaline cartilage 'model', a primary ossification center forms in the middle with a bone collar and periosteum on the outside. Blood vessels feed into it and the secondary ossification center towars the end. The primary ossification center becomes the medullary cavity, the hollow part in the middle of the bone, surrounded by compact bone and then periosteum on the outside. The secondary ossification center becomes thet epiphyseal plate, and the end is spongy bone, with articular cartilage on the outside.

Figure 3.2 * Bone Growth by rozwój kos«ci (public domain)

The top of this illustration shows an anterior view of the proximal end of the femur. The top image has two zoom in boxes. The left box is situated on the border between the diaphysis and the metaphysis. Its callout magnifies the periosteum on the right side of the femur. The view shows that the periosteum contains an outer fibrous layer composed of yellow fibers. The inner layer of the periosteum is called the cellular layer, which is composed of irregularly shaped cells. The cellular layer gradually shrinks in width as it transitions from the metaphysis to the diaphysis. A small blood vessel runs through both layers and enters the bone. The right zoom in box magnifies the endosteum on the left side of the bone. The box is situated just inferior to the border between the diaphysis and the metaphysic. It calls out the inner edge of the compact bone layer. The magnified view shows concentric circles of dark colored bone matrix. Between the circles are small cavities containing orange, diamond-shaped cells labeled osteocytes. The left edge of the bone matrix is lined with a single layer of flattened cells called the endosteum. There is a large cell, labeled an osteoclast, between two of the endosteum cells. The osteoclast is cutting a depression into the bony matrix under the endosteum. At another part of the endosteum, three smaller osteoblasts are secreting a blue substance that builds up the outermost layer of the bony matrix.

Figure 3.3 Periosteum and Endosteum by OpenStax, College Anatomy & Physiology, 6.3  * Bone Structure, 2018 (CC-BY-4.0)

Genetics determines most of what your bones look like. For example, your 23rd chromosomes determine several shapes that are commonly used to say whether someone looks male or female, and forensic anthropologists use these differences to identify the sex of a skeleton.

Illustration compares male and female pelvic bones. In both males and females, a wide, rounded bone called the ilium attaches to each side of the spine. The ilium curves toward the front, where it narrows into the ischium. A loop-shaped bone extends down from the place where the ilium meets the ischium, and connects back to the ilium in the front center of the body. The male pubic arch is like an upside-down 'V' and the female pubic arch is more like an upside down 'U'. The big hole in the pelvis, the pelvic outlet, is much bigger in the female.

Figure 3.4 to adapt to reproductive fitness, the female pelvis is lighter, wider, shallower, and has a broader angle between the pubic bones than the male pelvis. by OpenStax, College Biology, 38.1 * Types of Skeletal Systems, 2018 (CC-BY-4.0)

But like the rest of your body, the environment also effects your physical structures. The muscle attachments on your bones suggest your activities during your life, and stress, i.e. malnutrition, can be read in cross-sections of your teeth like tree rings.

It's important that we have a basic shared vocabulary so that we can compare humans to other vertebrates, to evaluate fossils, and to understand several aspects of human variation.

LEARN THE BONES OF THE HUMAN SKELETON BELOW:

human skeleton with names of major boneshuman skeleton

Figure 3.5 human female skeleton, red lines point to individual bones, blue lines point to groups of bones by Mariana Ruiz Villarreal, 2007 (Public Domain)

If you want to memorize these bones try clicking the blank one, print a few copies out, and practice writing the names of the bones. Check your spelling and try to learn the scientific names.

Common Name
Scientific Name
skull
cranium
jawbone
mandible
collarbone
clavicle
shoulder blade
scapula
breast bone
sternum
funny bone
humerus
spine
vertebrae
hips
pelvis
sit bone ischium
tail bone coccyx
broken hip
femur
thigh bone
femur
kneecap
patella
shin bone
tibia
ankle
tarsals
wrist
carpals

(adapted from George Claypoole http://hes.ucfsd.org/gclaypo/skelweb/skel03.html)

here's an online practice quiz with more detail then you need for this class, but good to know if you're going on to study anything health related.

skim animal skeletons

SKIM PRIMATE SKELETONS AND MORE PRIMATE SKELETONS

Vocabulary

Imagination Questions

one skeleton says to another 'Do you wanna hear a joke?' The other says, 'is it ... humerus'

Figure 3.6 hah-ah-ah-hahhahaha by Allison Zai from Skeletons © 2018 (permission pending)


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