Shoulder Anatomy

At the simplest level, the shoulder is a ball and socket joint. The upper part of the humerus (ball) fits into the socket portion of the scapula called the glenoid.

The shoulder is made up of three bones: the scapula (shoulder blade), the humerus (upper arm bone) and the clavicle (collarbone). The part of the scapula that makes up the roof of the shoulder is called the acromion.

The rotator cuff is responsible for the motion, stability, and power of the humerus.

The joint where the acromion and the clavicle join together is known as the acromioclavicular (AC) joint. There are ligaments that provide stability to this joint. The true shoulder joint is called the glenohumeral joint and consists of the humeral head and the glenoid. The rotator cuff muscles and their tendons play an important role in the correct functioning of this joint.

The shoulder is a very complex part of the body. The elegant design of the shoulder joint allows for a wide range of motion but not much stability. As long as the parts of the shoulder joint are in good working order, the shoulder can move freely and painlessly.

Some of the common symptoms of shoulder pain include pain, swelling, and stiffness. Shoulder pain may be isolated in the joint or felt within the muscles and tendons that surround and support the joint. Typically, shoulder pain will intensify when the joint is used.

Common causes of shoulder pain treated at Golden State Orthopedics & Spine include:

• Arthritis
• Bursitis
• Dislocated shoulder
• Rotator cuff tear
• Fractures
• Frozen shoulder
• Inflamed shoulder (shoulder impingement)
• Polymyositis (PM)
• Reflex sympathetic dystrophy (RSD) pain disorder
• Shoulder separation
• SLAP tear
• Sports injuries
• Sprains and strains
• Tendonitis especially biceps tendonitis

Sometimes, pain from conditions that affect the heart or abdomen (such as gall bladder disease) will lead to referred shoulder pain. This type of shoulder pain will not become worse when the joint is used. Referred shoulder pain may be a sign of a pressing health concern and should be evaluated by a physician.