The glenohumeral joint is the primary joint of the shoulder and the most mobile joint in the human body. It is a ball-and-socket synovial joint formed between the head of the humerus and the shallow glenoid cavity of the scapula.

This shallow socket allows extensive movement, including flexion, extension, abduction, adduction, internal rotation, and external rotation. However, this high mobility comes at the cost of stability.

Unlike the hip joint, which has a deep socket for structural support, the glenohumeral joint relies heavily on soft tissues such as the rotator cuff muscles, labrum, capsule, and ligaments for stability.

Because of this design, the shoulder is more prone to dislocation, impingement, and instability injuries. Therefore, rehabilitation focuses on strengthening dynamic stabilizers to maintain proper joint control.

Understanding the glenohumeral joint is essential in physiotherapy assessment and shoulder rehabilitation.