The human trunk
Our entire body is adapted to walking on two legs, an ability called bipedality. Bones of the human body have specific shapes that improve their function during bipedality. The hip bone, or pelvis, connects the legs to the rest of the trunk. The top of the pelvic bone, or ilium, is short and broad. It is shaped almost like a bowl, which holds up your guts. This bowl-like shape better supports the weight of your upper body. It also repositions the trunk muscles to both improve balance and leg movement. Repositioning these muscles creates better leverage, making them more efficient.
When did human ancestors begin walking on two legs and how do we know? Answer >>
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