Shoulder in 6: Adhesive capsulitis (frozen shoulder)

Sudden loss of motion, trauma with deformity The shoulder is the most mobile joint in the human body, formed where the ball of the upper arm bone sits in a shallow socket of the shoulder blade. This shallow fit allows an exceptional range of motion but provides little inherent bony stability, so the joint depends heavily on the surrounding rotator cuff muscles, ligaments, and labrum to stay centered during movement.

Shoulder pain is among the most common musculoskeletal complaints, particularly among adults over 40 and those in occupations or sports involving repeated overhead motion. Rotator cuff-related conditions account for a large share of cases, ranging from irritation of the tendons to partial or full tears.

Because the shoulder relies so much on muscular control, rehabilitation plays a central role in recovery for most conditions, whether managed conservatively or after surgery. This page covers the joint's anatomy, common conditions, assessment methods, and general exercise and recovery patterns.