What anatomical feature surrounds the shoulder joint?

The shoulder joint, also known as the glenohumeral joint, is surrounded by a joint capsule. The joint capsule is a connective tissue structure that encloses the joint, providing stability and support while allowing for a wide range of motions. This capsule is composed of fibrous tissue and synovial membrane, which produces synovial fluid that lubricates the joint. The joint capsule plays a crucial role in maintaining the integrity of the shoulder joint by limiting excessive movements that could lead to injuries or dislocations.

While articular cartilage, the synovial membrane, and the subacromial bursa all contribute to the function and health of the shoulder joint, they do not exclusively surround the joint. Articular cartilage covers the surfaces of the bones at the joint to reduce friction, the synovial membrane lines the interior of the joint capsule and produces the joint fluid, and the subacromial bursa acts as a cushion to reduce friction between the shoulder structures. However, it is the joint capsule that forms the outer boundary of the shoulder joint space.