What shape is the articular cartilage of the acetabulum?

The articular cartilage of the acetabulum is indeed shaped like a horseshoe. This specific shape is crucial as it allows for a more extensive surface area that facilitates the movement of the femoral head in the hip joint, contributing to stability and support as well as allowed range of motion. The horseshoe shape helps accommodate the spherical shape of the femoral head while providing optimal contact during various motions, such as flexion and rotation of the hip.

In contrast, a spherical shape would imply a uniform surface that may not align appropriately with the femoral head throughout its range of motion, while a cylindrical shape is not consistent with the structural anatomy of the acetabulum. A triangular shape would lack the necessary curvature to support effective joint function and load distribution. Therefore, the horseshoe shape is uniquely suited to the specific biomechanical demands placed on the hip joint.