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SNAPPING SCAPULA SYNDROME
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A PATIENT'S GUIDE TO SNAPPING SCAPULA SYNDROME
The scapulothoracic joint is located where the shoulder blade (also called the scapula) glides along the chest wall (the thorax). When movement of this joint causes feelings or sounds of grating, grinding, popping, or thumping, doctors call it snapping scapula syndrome.
Snapping scapula syndrome is fairly rare. When it happens, the soft tissues between the scapula and the chest wall are thick, irritated, or inflamed. Snapping scapula syndrome can also happen if the bones of the shoulder blade or rib cage grate over one another.
This guide will help you understand
what causes snapping scapula syndrome
how doctors treat this condition
What parts of the body are involved in this condition?
The shoulder is made up of three bones: the humerus (upper arm bone), the clavicle (collarbone), and the scapula(shoulder blade). Two large muscles attach to the front part of the scapula where it rests against the chest wall. One of them, called the subscapularis muscle, attaches over the front of the scapula where it faces the chest wall. The serratus anterior muscle attaches along the edge of the scapula nearest the spine. It passes in front of the scapula, wraps around the chest wall, and connects to the ribs on the front part of the chest.
A bursa is a fluid-filled sac that cushions body tissues from friction. A bursa sits between the two muscles of the scapula. There is also a bursa in the space between the serratus anterior muscle and the chest wall. When bursa sacs become inflamed, the condition is called bursitis.
Scapulothoracic bursitis refers to inflammation in the bursa under the shoulder blade. This type of bursitis is most common in the upper corner of the scapula nearest the spine. It also occurs under the lower tip of the scapula. In either case, it can cause the sounds and sensations of snapping scapula syndrome. A person can have bursitis in the joint without any grinding or popping.
Related Document: A Patient's Guide to Shoulder Anatomy
What causes this condition?
Snapping scapula is caused by problems in the soft tissues or bones of the scapula and chest wall. It can start when the tissues between the scapula and shoulder blade thicken from inflammation. The inflammation is usually caused by repetitive movements. Certain motions of the shoulder done over and over again, such as the movements of pitching baseballs or hanging wallpaper, can cause the tissues of the joint to become inflamed.
In other cases, the muscles under the scapula have shrunk (atrophied) from weakness or inactivity. The scapula bone then rides more closely to the rib cage. This means the scapula bumps or rubs on the rib bones during movement.
Changes in the alignment or contour of the bones of the scapulothoracic joint can also cause snapping scapula. When a fractured rib or scapula isn't lined up just right, it can cause a bumpy ridge that produces the characteristic grind or snap as the scapula moves over the chest wall.