Anatomy of Bipedalism

  • Human vs. Great Ape AnatomyShorter/broader pelvis

  • Valgus angle

  • Knee

  • Lengthened lower limbs

  • Enlarged joint surfaces

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Slide 78 of 109

Bipedalism is not a simple anatomical adaptation, but involves changes to most of the skeletal system. Humans have a shorter, broader pelvis than apes. The human femur (upper leg bone) forms an angles of less than 90° with the knee, whereas in the ape, the angle is nearly 90°. The human knee has the ability to be fully extended, whereas the ape knee cannot do so. The lower leg bones are longer in the human compared to apes. In addition, joint surfaces are enlarged in humans to compensate for the added stress of bipedal locomotion.


Valgus angle
The angle the femur (upper leg bone) makes relative to the knee. About 90 degrees in apes, less in bipeds.
Last Modified June 21, 2006


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