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ANT203 November 22.pdf

Course Code
Xueda Song

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Post-cranial skeleton of n-h primates cnt'd
to determine morphology:
cranial skeleton: think of brains and diets
post-cranial: think in terms of locomotion
on primate forelimbs:
human humerus: large joint surface at shoulder
indicates either a large amount of mobility, or weight-bearing
gorilla humerus: also a large joint surface at shoulder - important for both
mobility and weight bearing (knuckle walking)
curved, robust bone
distal end, when articulated with the ulna - elbows capable of
baboon humerus - imagine if arboreal and running through the trees
restricted shoulder joint; cannot lift arms above head like apes,
humans, and a few monkeys can
distal end: elbow joint remains prevents full extension (always
roughened part of cortical bone on humerus indicates attachment site for
not huge in humans, since we don't hang from trees often
very large in orangutans and other apes, however
humans: fairly short
proximal end: very circular, large joint surface
gorilla + other great apes: significantly longer, and a bit curved
proximal end, as in humans, is very circular and has a large joint
surface, for a good range of elbow rotation
baboon: very small, since they aren't forelimb dominant
proximal end in baboon is not very large
humans: fairly large, because must articulate with a number of bones
at the wrist
great apes: very large
baboon: small joint surface, even to scale
having a broad range of motion in the wrist is not
particularly beneficial for running through trees
tiny projection (process) of bone, because the wrist
articulates with both the radius and the ulna
in humans and great apes: large attachment site for biceps

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in humans and great apes: large attachment site for biceps
in great apes and humans, there's not much bone buildup around the elbow
joint, allowing for hyper-extension and extension, respectively
the baboon has an area of bone that acts like a doorstop to prevent full
extension of the elbow joint
primate hands
ape hands: designed for grasping, so very large
humans also need to grasp, but precision is more important
human: grassile bones, not particularly long
gorilla: more robust and longer bones, since the bones need to bear some
weight for knuckle-walking
slightly curved, useful for tree climbing
chimpanzee: basically a scaled-down gorilla
orangutan: very curved phalanges (like a hook to facilitate movement in
gibbons: very long fingers relative to body size; very curved
huge emphasis on this digit in humans
the thumb in apes is very reduced given the size of the other fingers
primate pelvic girdles
very broad, thick and robust bones for weight distribution
sacrum: thick, strong bone, ideal for weight bearing
taller and narrower
oriented differently from humans; basically just serves to attach the lower
sacrum (ex. in gorilla): much taller, but more narrow
not robust
primate hindlimbs
humans - hind-limb dominant
valgus angle
ape or monkey
straight shaft (no angle)
relatively short bone
proximal end
human and chimp both have a small depression in this area, called a
fovea, for the attachment of the teres ligament
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