Final answer:
The Iliac blade faces more laterally in humans, especially in females due to the wider pelvis that accommodates childbirth, affecting the orientation of attached hip muscles and overall biomechanics.
Step-by-step explanation:
In humans, the Iliac blade faces more laterally, which changes the orientation of the hip muscles by affecting the pelvic shape and muscle attachments. The iliac blade is part of the ileum, which in females is adapted to accommodate childbirth. A wider pelvis in females leads to changes in various anatomical features such as the iliopsoas and gluteal muscles, which attach to the hip bone and femur. These muscles hence have differing angles of attachment and function slightly differently due to the broader pelvic structure. The differences in the female pelvis not only influence muscle orientation but also impact a woman's gait and the angle of the femur (Q-angle), which has further implications on biomechanics and susceptibility to certain types of injuries, such as patellofemoral syndrome. The female pelvis is characterized by a greater width, an increased subpubic angle, and a more rounded pelvic inlet, which directly affects the positioning and function of the associated musculature. Moreover, the broader sciatic notch in females facilitates a wider spacing of hip muscles.