The muscles and joints of the shoulder make it the most mobile joint in the human body.


Biceps Tendon

The biceps tendon attaches the biceps muscle to the bone at the top of the shoulder socket. It sits in a groove at the front of the humerus.

Coracoacromial Ligament

The coracoacromial ligament is a bridge ligament attaching the acromion bone end to the coracoid process.


Between the rotator cuff muscles and the larger surrounding muscles lies the bursa. This is pocket of lubricating fluid allow muscles to move freely over each other.

Rotator Cuff

The rotator cuff muscles and tendons raise and lower the arm from the side. The rotator cuff also helps stabilize the shoulder joint by holding the humeral head in the socket.


The labrum, a ring of fibrous cartilage, surrounds the glenoid in the scapula. It helps attach the head of the humerus to the scapula.


The humerus is also known as the upper arm bone.

Humerus Head

The head portion of the humerus bone is covered by smooth cartilage, which glides over the shoulder joint cavity.


The scapula, or shoulder blade, is the large triangular bone located on the back side of the upper body.


This shallow cavity in the scapula is where the humerus head is inserted.


The acromion projects forward from the top of the scapula to form the ìroofî of the shoulder.


The clavicle, also called the collarbone, attaches the shoulder to the rib cage and holds the shoulder out from the body.

Acromioclavicular Joint

The AC joint connects the acromion and clavicle bones. The ends of the bones are covered with cartilage, which allows smooth movement and protects the bones.

Coracoid Process

The coracoid process and the acromion form the ìroofî of the shoulder. The coracoid process, acromion and glenoid form the socket in which the humerus head is cradled.