The Shoulder Joint

The shoulder is made up of bones, muscles, ligaments, and tendons. They work together so you can reach, swing, and lift in comfort. Learning about the parts of the shoulder joint will help you to understand your shoulder problem.

The parts of the joint

Front view of shoulder joint with muscles.

The shoulder joint is where the humerus (upper arm bone) meets the scapula (shoulder blade):

  • Muscles and ligaments help make up the joint. They attach to the shoulder blade and upper arm bone.

  • At the top of the shoulder blade are two bony knobs called the acromion and coracoid process.

  • The subacromial space is between the top of the humerus and the acromion. This space is filled with tendons, muscles, and the subacromial bursa.

  • The bursa is a sac of fluid that cushions shoulder parts as they move.

  • The supraspinatus muscle and tendon are located in the subacromial space. They help form the rotator cuff and are commonly injured in a rotator cuff tear.

  • The rotator cuff is a group of muscles and tendons that surround the shoulder joint. These muscles and tendons hold the arm in its joint. They also help the shoulder move and rotate.