Final answer:
The iliacus muscle functions to flex and rotate the thigh at the hip joint, while the inguinal ligament provides support to the abdominal wall. The hip joint and stability of the pelvis involve various muscles and ligaments, including the iliacus muscle and iliofemoral ligament.
Step-by-step explanation:
The function of the iliacus muscle is primarily to flex and rotate the thigh at the hip joint. It is part of the iliopsoas group along with the psoas major, and these muscles work together to produce movement at the pelvic girdle and lower limb. The inguinal ligament, on the other hand, forms the base of the inguinal canal and helps support the abdominal wall. This ligament extends from the anterior superior iliac spine to the pubic tubercle.
Proper understanding of the appendicular muscles of the pelvic girdle and lower limb is essential as they play a critical role in movement and stability. The hip joint is a vital junction where these muscles, including the iliacus, enable the lower limb to perform a range of motions. On the other hand, an intrinsic ligament like the iliofemoral ligament also contributes to hip stability, spanning from the ilium of the hip bone to the femur.
Ligaments like the sacrospinous and sacrotuberous contribute to the structure and stability of the pelvis, whereas the movement and function of the pelvic girdle and lower limb are facilitated by numerous muscles and ligaments including the iliacus muscle and iliofemoral ligament.