The scapula is the shoulder blade.

The scapulothoracic joint is located between the shoulder blade (scapula) and the back of five upper ribs. It allows the shoulder to move forward and backward.

This sac encloses and supports the shoulder joint. It is also called the articular capsule.

A SLAP lesion is an injury to the labrum, the fibrous rim of tissue surrounding the "socket" portion of the shoulder. SLAP describes how the tendon tears: Superior Labral tear from Anterior to Posterior.

The sternoclavicular joint is at the junction between the collarbone (clavicle) and breastbone (sternum). It anchors the shoulder to the wall of the chest.

Synovial fluid is a fluid produced by cells lining the joint capsule or synovium. This fluid lubricates the joint surfaces and provides cartilage with nutrients.

Synovitis occurs when synovium (inner layer of a joint capsule) is inflamed. It results in pain and loss of range of motion.

Your shoulder joints are held together by a "capsule" of tissues and ligaments. The innermost tissue of the capsule is a membrane called the synovium.