Hill-Sachs lesion

A Hill-Sachs lesion is a common injury that occurs when the upper arm bone (humerus) shoulder socket is dislocated. During the dislocation, the back part of the humeral head (ball) hits the front edge of the shoulder socket (socket), causing a small dent or groove in the bone. This dent is called a Hill-Sachs lesion. It can sometimes make the shoulder more prone to future dislocations or instability, especially if the lesion is large. Treatment depends on the severity and symptoms, and may involve physical therapy or surgery.