Which part of the bone increases joint stability?

The epiphyses, which are the ends of long bones, are critical for joint stability as they have a specific shape that contributes to the fit and congruence of the joint surfaces. This anatomical structure is covered with articular cartilage, which not only reduces friction but also absorbs shock during movement, enhancing stability. Moreover, the epiphyses house numerous ligaments and tendons that attach to the bone, providing additional support and enhancing the overall stability of the joint.

The diaphysis, which is the shaft of the bone, primarily provides structural support and is less involved in direct joint articulation. The medullary cavity, located within the diaphysis, serves as a space for bone marrow but does not contribute to joint stability. The growth plate, or epiphyseal plate, is involved in the longitudinal growth of the bone and closes when the individual reaches skeletal maturity, but it does not enhance stability in a mature joint. Hence, the epiphyses are essential for maintaining joint stability through their design and associated structures.