Which statement about the glenohumeral joint is correct?

• A. It is a true synovial joint and the most mobile joint in the human body
• B. It is a hinge joint
• C. It has no ligaments
• D. It is a fibrous joint

Answer: (A)

The glenohumeral joint is a ball-and-socket synovial joint formed by the head of the humerus and the glenoid cavity of the scapula, which allows a vast range of motion in multiple directions. Because it is a true synovial joint, it has a joint capsule with a synovial lining and fluid, articular cartilage, and reinforcing ligaments, plus dynamic stabilization from the rotator cuff. This combination makes it the most mobile joint in the body, capable of flexion, extension, abduction, adduction, internal and external rotation, and circumduction. The other statements are inconsistent with its anatomy: it is not a hinge joint, it does have ligaments, and it is not a fibrous joint.