The snapping scapula Syndrome. Snapping scapula is a condition causing painful grinding, clicking, or snapping of the shoulder blade. The shoulder joint itself is called the glenohumeral joint. The shoulder separation occurs at the acromioclavicular joint, but the snapping scapula occurs at the scapulothoracic joint. It’s a different joint.

You can see the arrow pointing towards the scapulothoracic joint Over one third of the shoulder movement occurs between the scapula and the thoracic cage.

You can see the Bursa underneath the scapula protecting the movement of the shoulder between the scapula and the thoracic cage

The shoulder blade serves as an anchor for the subscapularis and serratus anterior muscle. These muscles as well as small Bursa, provides for a smooth movement of the shoulder. When the muscles are weak or inactive, The scapula will rub on the ribs causing the grinding clicking movement. Snapping scapula can be caused by a repetitive movement that leads to inflammation of the Bursa or atrophy of the muscle under the scapula.

When the scapula cannot easily glide along the chest wall, the bones rub together and produce the characteristic noise sensation and painful clicking and grinding. Snapping scapula can also be secondary symptoms to shoulder instability and dislocation or nerve disorder that lead to atrophy and weakening of the muscle.

The patient may develop scarring and fibrosis of the Bursa as well as a painful scapula crepitus when moving the shoulder blade.

What are the common causes of snapping scapula syndrome?

• Weakness. Wasting atrophy of the scapula muscles ( that stabilizes the shoulder )
• Bursitis
• Osteochondroma
• Rib or scapula fractures.
  

What is the differential diagnosis of snapping scapula syndrome?

What is the differential diagnosis Feeling a click in the shoulder or in the scapular area? The snapping noise may originate from other areas of the shoulder beside the shoulder blade,

1. Biceps tendon subluxation.

The biceps tendon subluxation. The biceps tendon will sublux out of the groove causing a snapping sensation in front of the shoulder.

2. labral tear.

A labral tear may cause a clicking sound during movement of the shoulder.

Treatment of snapping scapula

• Physiotherapy
• Injection of the Bursa.

Physiotherapy to improve the stability and the coordination of the scapula muscles. Injection of the Bursa. The arm usually held in a position of extension, internal rotation and adduction, with the patient lying prone, sometimes standing and this will make the scapula more prominent. The needle should be placed under the scapula to inject the Bursa.

Please avoid puncturing the pleura. You may need chest x ray after that injection. Some Source Here..

This is a picture of a patient that positioned for a blind injection of the scapulothoracic joint. This is a patient positioned for fluoroscopic injection of the scapulothoracic joint. You can see the position of the fluoroscopy machine preparing for injection of the scapulothoracic joint, allowing us to get a wide view of the scapula.

The needle is inserted into the scapulothoracic joint under fluoroscopy with the aid of scapular y view x ray. You must obtain a contour of the scapula that project as a y view on the x ray and separate it from the ribs. Inject between both under the scapula. Surgery is rare. Is done for debridement of the Bursa or for removal of the bony bump. The debridement is done either open or arthroscopically