Shoulder Anatomy Explained
Very frequently in practice I see patients who come into the office complaining of “ pain in my shoulders” when they are in fact referring to the upper thoracic and lower cervical regions instead of the shoulder joint.
This is a simplified shoulder anatomy description so you can better understand the shoulder structure and be able to differentiate pain in that region with other kind of pain.
Main Shoulder Bones and Joints
The three main bones that make up the shoulder joint are the humerus, the scapula and the clavicle.
The Four Shoulder Joints
1. Glenohumeral joint– Composed of the glenoid (the articulating surface of the scapula) and the head of the humerus
2. Sternoclavicular joint– The medial end of the clavicle and its attachment on the sternum
3. Acromioclavicular joint– Formed by the lateral edge of the clavicle with the acromion process of the scapula
4. Scapulothoracic joint– articulation of the scapula with the posterior thoracic wall
Ligaments serve to connect the bones of the shoulder to one another. They are referred to as passive stabilizers, functioning even without the muscles to keep the joint intact.
Tendons are located around the shoulder joint and connect muscles to bone to allow for movement. Their placement serves to further stabilize the joint. Because they are connected to the muscles, tendons stabilize the joint actively (as compared to what the ligaments do passively) when the muscles contract.
The rotator cuff is composed of four small, short muscles that start from the scapula working their way around the shoulder where their tendons merge and attach on the humerus. These muscles are also called “SITS” muscles:
3. Teres minor
These muscles have two main functions:
1. Stabilize the joint and center the humeral head in the glenoid fossa amid all motion.
2. Control rotation of the shoulder and allow for complex movements.
According to the Centers for Disease Control and Prevention (CDC), about 13.7 million people in the US required medical treatment for shoulder pain in 2003. The incidence of shoulder pain increases with age. Rotator cuff problems, for example, are more common in people age 60 years and above.
Besides neck and back pain, chiropractors can evaluate and treat some of the common shoulder conditions or will refer to other specialists like orthopedic physicians if necessary.
If you think you may be dealing with a shoulder condition, give us a call—we might be able to help.