Female torso skeleton. The bones of the chest and abdomen surround and protect the organs and provide support for the body. The ribcage (upper frame) encloses the heart and lungs. The pelvis (at bottom) forms the base of the abdominal cavity. The female pelvis is wider, and the ischia (loops of bone at bottom) meet at a more obtuse angle than in the male. These structural differences in the female facilitate the passage of a baby during childbirth. For a male torso skeleton, see image P116/487.