Final answer:
The pelvic girdle comprises the hip bones, each consisting of fused ilium, ischium, and pubis, and connects the lower limbs to the axial skeleton. The lower extremity includes the femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges. Bony landmarks, ligaments, and muscles all contribute to the function and stability of these structures.
Step-by-step explanation:
The pelvic girdle is a bony structure that connects the lower limbs to the axial skeleton. It is formed by two large hip bones, known as the coxal bones, each composed of three fused bones: the ilium, ischium, and pubis. These hip bones join anteriorly at the pubic symphysis and posteriorly with the sacrum.
The lower extremity includes bones such as the femur (thigh bone), patella (kneecap), tibia and fibula (lower leg bones), as well as the tarsals (ankle bones), metatarsals (foot bones), and phalanges (toe bones). The femur attaches to the acetabulum of the pelvic girdle, creating the hip joint, which is critical for bearing the body's weight and allowing locomotion.
Beyond the bony architecture, the pelvic girdle and lower extremity are connected and supported by various ligaments and muscles that facilitate movement and provide stability. The different regions of the hip bone have identifiable bony landmarks and are involved in the formation of the pelvis's greater and lesser openings, which demarcate the boundaries of the true (lesser) and false (greater) pelvis.