APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -The curvature in the lower back (lumbar lordosis) helps balance the upper body over the pelvis. In the upper half of the pelvis, the size, shape and orientation of the iliac blades differ between apes and humans in a way that reflects our commitment to striding bipedal locomotion (figure 1).

Detailed explanation-2: -Balance of the whole vertebral column over the hip joints is a major contribution for efficient bipedalism.

Detailed explanation-3: -This width, when combined with the horizontal rotation of the pelvis, minimizes the vertical displacement of the center of mass during bipedal walking. A different manner of reducing this vertical displacement and of diminishing its undesirable effects is the elongation of the lower limbs.

Detailed explanation-4: -Human bipedalism is promoted by a narrow pelvis. However in mammals the pelvis is also the passage through which newborn babies pass, and the birth canal must be sufficiently large to accommodate a birth.