Where does the head of the femur fit?

• A. Shoulder
• B. Wrist
• C. Knee
• D. Acetabulum

Answer: (D)

The head of the femur fits into the acetabulum, which is a cup-shaped socket located in the pelvis. This anatomical feature is crucial for the formation of the hip joint, where the femur (thigh bone) connects to the pelvic girdle. The articulation between the head of the femur and the acetabulum allows for a wide range of motion in the hip joint, including flexion, extension, abduction, adduction, and rotation, enabling activities such as walking, running, and jumping.

In contrast, the shoulder joint involves the humerus fitting into the glenoid cavity of the scapula, not the head of the femur. The wrist is related primarily to the interactions of the radius and ulna with carpal bones, while the knee joint comprises the femur, tibia, and patella, where the head of the femur does not make direct contact with any bone in the knee. Thus, understanding the specific joints and their components is essential for grasping human anatomy and biomechanics.