What is the distal joint surface of the hip joint?

The correct answer is the convex head of the femur. In the anatomy of the hip joint, the joint is a ball-and-socket type, which consists of the spherical head of the femur fitting into the socket formed by the acetabulum of the pelvis. The head of the femur is considered the distal joint surface because it articulates directly with the acetabulum, providing the main surface for movement and stability of the hip joint.

Understanding the nature of this articulation is crucial for grasping how the hip functions biomechanically. The shape of the femoral head allows for a wide range of motion, including flexion, extension, abduction, adduction, and internal and external rotation. This makes it essential in both locomotion and weight-bearing activities.

In contrast, the acetabulum serves as the socket but is not the distal joint surface; rather, it is the proximal surface of the joint. The greater and lesser trochanters are bony protrusions on the femur that serve as attachment points for muscles but are not part of the joint surfaces.