Rotator Cuff Injury

There are two major causes of shoulder injuries. The first being degeneration, or wear and tear. The second cause is due to unusual accidental exposure to excessive force, or simply putting repetitive strain on the tendons of the shoulder muscles.

The two most common symptoms of shoulder injury are pain and weakness.

A careful evaluation of the presenting history and physical examination is very important in diagnosing the condition.

Several types of advanced imaging techniques, such as MRI arthrography and ultrasonography, may be performed if physical examination is not sufficient to rule out the cause.


The most preferable way to treat shoulder impingement is through a consistent exercise program to strengthen the muscles sufficiently so that the head of the shoulder is held firmly in place and does not slip out of the socket.

To understand about Rotator Cuff Injury one has to know understand about the shoulder joint and how it functions.

Overview About Shoulder Joint - Our shoulder is a ball and socket joint made up of two major bones, humerus or the arm bone and glenoid capsule of the scapula or shoulder blade. The head of the humerus acts as ball and the glenoid capsule acts as socket. A portion of the scapula called the acromion joins the outer end of the clavicle or collar bone to form the "acromioclavicular joint." The shoulder is dependent on its soft tissues to maintain the stability of the joint. These soft tissues include:

Ligaments, which join bone to bone;

Tendons, which attach muscle to bone;

Muscles, which both move and stabilize the bones

Bursa, one of the cushioning pads between tendon and bone,

Most important in stabilizing the shoulder is the rotator cuff. Rotator cuff includes muscles around the scapula. These rotator cuff muscles and tendons help in moving the shoulder. They are:

1. Supraspinatus: The supraspinatus muscle is responsible for the motion of abduction which means lifting up your arm overhead and out to the side. The supraspinatus originates from the upper end of scapula, and inserts into the greater tuberosity or a prominence of the humerus. The supraspinatus provides stability to the head of the humerus and helps keep the head of the humerus from slipping out of the socket.

2. Infraspinatus: The infraspinatus is the largest rotator cuff muscle whose primary motion is to externally rotate the humerus. The infraspinatus originates just below the middle two third of the spine of scapula.

3. Teres Minor: The teres minor muscle originates near the infraspinatus muscle on the back of the scapula. The teres minor works along with the infraspinatus muscle to externally rotate humerus.

4. Subscapularis: The subscapularis muscle is responsible for internal rotation of humerus. If you try to take your hand to your nose, your humerus gets internally rotated. It originates on the front of the scapula and runs forward, forming a part of the posterior fold of the armpit wrapping around the inner upper shaft of the humerus and gets inserted there.