capsular ligament

A capsular ligament, also known as a joint capsule, is a structure composed of collagen fibers that connects two articulating bones. These ligaments are thickenings of the fibrous capsule itself and can appear as bands or triangles. They are typically found on the outer surface of the capsule, with the shoulder joint being a notable exception where they are located on the inner surface.1

Capsular ligaments play a role in stabilizing joints. While ligaments are not typically responsible for holding joint surfaces together during normal resting states, they can prevent excessive movement by tightening when stretched. Muscles and gravity usually keep the bones pressed together at a joint. However, certain movements can bring the joint into a "close-packed" position, where the articular surfaces are screwed firmly together, and the capsule and ligaments are maximally taut.1

It is important to distinguish this from "capsular contracture," which refers to the shrinking and tightening of scar tissue around a structure, such as a breast implant, potentially causing pain and distortion.2