Comparative Anatomy of the Axial Skeleton, Arm, and Hand
Use eSkeletons to compare the lumbar vertebrae of great apes and modern humans.
What differences do you see? In particular, pay attention to the last lumbar vertebra.
Which specimen displays a vertebral body that significantly shortens posteriorly? This anteroposterior “wedging” is a distinct feature of modern humans and helps maintain the lumbar lordosis. What behavior is the L5 “wedging” most-likely related to?
Compare the overall curvature of the modern human and great ape vertebral column. What differences do you see? If early hominins had an L5 similar to modern humans, what would you estimate the vertebral column to look like in these animals?
Compare the overall shape of the modern human and great ape rib cages. Which of these thoracic shapes is seen in early hominin specimens such as A. afarensis (“Lucy”)? Why, in part, does thoracic shape differ between great apes and modern humans?
Below is a reconstruction of the glenoid fossa in an early hominin (Australopithecus afarensis, “Lucy”). Compare the orientation of the glenoid fossa in a modern human, great ape, and early hominin. What differences do you see? Is the early hominin glenoid fossa more similar to modern humans or African apes?
