Joint capsule

The joint capsule is an envelope of dense fibrous connective tissue that surrounds a synovial joint, consisting of two layers: an outer fibrous membrane and an inner synovial membrane. It seals the joint space, provides passive and active stability, limits excessive movements, and is attached to bones via specialized attachment zones. The capsule varies in thickness depending on local mechanical stress and may incorporate ligaments and tendons. It is clinically significant in diseases such as rheumatoid arthritis, osteoarthritis, crystal deposition disorders, ankylosing spondylitis, as well as injuries and conditions like frozen shoulder and plica syndrome. The joint capsule is not a molecular therapeutic target but rather a macro-anatomical structure made of collagen-rich connective tissue, responding to injury and disease primarily through structural and pathological adaptations.

Other names

articular capsule

None (no mechanism of action as a molecular target; tissue manipulation sometimes involves surgery or corticosteroid injection for inflammation)