The articulation between the head of the femur and the acetabulum is which type of joint?

• A. Ball and socket joint
• B. Pivot joint
• C. Hinge joint
• D. Saddle joint

Answer: (A)

A ball-and-socket arrangement best fits the hip joint. The head of the femur is a rounded ball that fits into the cup-shaped acetabulum of the pelvis, forming a ball-and-socket synovial joint. This setup allows movement in multiple directions: flexion and extension, abduction and adduction, internal and external rotation, and even circumduction. The joint is stabilized by the deep socket, the acetabular labrum, and a strong fibrous capsule with reinforcing ligaments.

Other joints described would not permit the same range of spherical movement. A pivot joint rotates around a single axis, a hinge joint mainly bends in one plane, and a saddle joint allows two directions of movement but not the full ball-in-cup rotation.