Which joint is the most commonly dislocated in the body?

Which joint is the most commonly dislocated in the body?

• A. AC joint
• B. Patellofemoral
• C. Shoulder (Glenohumeral)
• D. Temporomandibular joint

Answer: (C)

The shoulder joint (glenohumeral) is the most commonly dislocated because it has the greatest range of motion of any joint, which comes at the cost of stability. The ball-shaped humeral head sits in the shallow glenoid fossa, so bony constraints are minimal. Stability largely depends on soft tissues—the joint capsule and ligaments, the glenoid labrum, and especially the rotator cuff muscles that provide dynamic stabilization. When a force pushes the arm into abduction and external rotation (common in falls or sports injuries), the humeral head can be driven forward out of the socket. That combination of wide mobility and relatively lax structural constraint makes dislocations far more likely here than in other joints. Most dislocations involve the anterior portion of the humeral head, which aligns with the typical injury mechanism and clinical presentation. In contrast, other joints like the acromioclavicular joint can be injured, but such injuries are less frequent overall; patellofemoral dislocations occur mainly in young, active people and are less common than shoulder dislocations; temporomandibular joint dislocations are relatively rare and usually require unusually wide mouth opening or significant trauma. Clinically, a dislocated shoulder often presents with pain and an inability to lift the arm, sometimes with a visibly squared-off contour and loss of the normal shoulder curve.Neurologic risk exists, notably involving the axillary nerve, which can affect sensation over the outer shoulder (regimental badge area) and deltoid strength.

The shoulder joint (glenohumeral) is the most commonly dislocated because it has the greatest range of motion of any joint, which comes at the cost of stability. The ball-shaped humeral head sits in the shallow glenoid fossa, so bony constraints are minimal. Stability largely depends on soft tissues—the joint capsule and ligaments, the glenoid labrum, and especially the rotator cuff muscles that provide dynamic stabilization. When a force pushes the arm into abduction and external rotation (common in falls or sports injuries), the humeral head can be driven forward out of the socket. That combination of wide mobility and relatively lax structural constraint makes dislocations far more likely here than in other joints.

Most dislocations involve the anterior portion of the humeral head, which aligns with the typical injury mechanism and clinical presentation. In contrast, other joints like the acromioclavicular joint can be injured, but such injuries are less frequent overall; patellofemoral dislocations occur mainly in young, active people and are less common than shoulder dislocations; temporomandibular joint dislocations are relatively rare and usually require unusually wide mouth opening or significant trauma.

Clinically, a dislocated shoulder often presents with pain and an inability to lift the arm, sometimes with a visibly squared-off contour and loss of the normal shoulder curve.Neurologic risk exists, notably involving the axillary nerve, which can affect sensation over the outer shoulder (regimental badge area) and deltoid strength.