Final answer:
The 'big wings of the hips' likely refers to the iliac crest, part of the pelvic girdle which includes ilium, pubis, and ischium. The pelvis features structural differences between sexes and serves as an attachment point for muscles crucial for stabilization and movement.
Step-by-step explanation:
The 'big wings of the hips' you're referring to are likely the iliac crests, which are part of the pelvic girdle. The pelvic girdle comprises the ilium, pubis, and ischium, which are fused bones that form the hips and attach the legs to the trunk. One notable feature of the pelvis is the ischial tuberosity, a large, roughened protuberance serving as a weight-bearing region when sitting. It also features the acetabulum, a large, cup-shaped cavity that holds the head of the femur, forming the hip joint.
The pelvis has differences between sexes; females have a larger subpubic angle than males. This angle is formed between the pubic bones at the base of the pelvis. Additionally, the pelvic girdle serves as an attachment point for multiple muscles, including the powerful gluteal group, which aids in stabilizing and moving the body.
If the pelvic girdle had a range as wide as the pectoral girdle, it would significantly impact stability and walking efficiency since the pelvis houses the body's center of gravity. To compensate for a limited range of motion, the muscles connected to the pelvic girdle, especially those inserting on the femur, such as the gluteal group, exhibit size and power to facilitate body stabilization and movement.