Dislocated Shoulder: Symptoms, Causes, and Care

A shoulder dislocation occurs when the rounded ball at the top of the upper arm bone (humerus) is forced out of the socket in the shoulder blade (scapula). This means that the ball and socket bones of the shoulder have separated, with the ball of the humerus no longer in its proper position. When this happens, the surrounding tissues that stabilize the joint—including muscles, tendons, and ligaments—can also be damaged. These structures are crucial for holding the shoulder joint together. Additionally, the dislocation may result in a tear of the cartilage, a flexible tissue that cushions and protects the ends of bones within the joint.

In some cases, the dislocation is partial, known as a shoulder subluxation, where only a portion of the humerus shifts out of the socket. The shoulder joint is a highly mobile ball-and-socket mechanism, where the round head of the humerus fits into a shallow groove in the scapula. This design allows the shoulder to move in multiple directions, making it the most flexible joint in the body. However, this very flexibility can also lead to instability, even though the joint is reinforced by muscles, tendons, and ligaments. Among all the joints in the body, the shoulder is the most prone to dislocations. 

A dislocated shoulder presents with several clear symptoms. These may include intense pain, an inability to move the arm, and visible deformity, as the shoulder may appear visibly out of place. Swelling, bruising, and weakness in the shoulder and arm are also common. In severe cases, nerve damage or blood vessel injury can occur, which may cause tingling, numbness, or a bluish color in the arm.