The arm is kept in the shoulder by the rotator cuff, a group of muscles that come together as tendon to cover the head of the humerus. The rotator cuff attaches the humerus to the shoulder blade and helps in lifting and rotating the arm.
The bursa, a lubricating sac between the rotator cuff and the bone on top of the shoulder, allows the rotator cuff tendons to glide freely when moving the arm.
When the rotator cuff tendons are damaged, bursa becomes inflamed and painful. When one or more these tendons are torn, they get detached the Humerus’s head. The damage starts with fraying of the torn tendons before progressing to complete tears. There are two types of tears:
- Partial Tear or Incomplete tear : damages the tendon but doesn’t sever it completely.
- Complete Tear : the tendons are completely separated from the bone.
Causes
There are two main causes for this injury:
- Acute Tearing after injury
Falling or landing on outstretched arm, lifting heavy objects quickly etc., are some of the reasons for rotator cuff tears. Even shoulder injuries like broken collar bone or dislocated shoulder can cause a rotator cuff tear.
- Degenerative Tearing
Most tendon tears occur gradually over time, the degeneration process naturally happens as we age. This is most common in our dominant arm and once one arm has a rotator cuff tear, there are chances of the other arm getting one too.
Some contributing factors are:
- Repetitive Stress : repetition of the same shoulder actions stresses the rotator cuff muscles and tendons leading to tears. Sports like Baseball, Tennis, Rowing and weightlifting allow for overuse tears. Even some jobs or routine chores cause overuse tears.
- Lack Of Blood Supply : Blood supply in tendons lowers, as we grow older and impair the body’s natural ability to repair tendon damage or tear.
- Bone Spurs : Bone overgrowth develops below the acromion bone. When the arms are lifted, these spurs rub on the rotator cuff tendon and weaken the tendon leading to tear.
Symptoms
- Varying pain in the shoulder and shoulder depending on the severity
- Disturbed sleep when lying on affected shoulder
- Difficulty in moving shoulder, to reach behind the back or overhead.
- Weakness of arm
- Snapping or crackling sounds when moving the shoulder.
Diagnosis and Treatments
In a physical examination, the doctor will perform a series of tests in which
- Shoulder joints are moved around to see which movements cause the pain.
- Strength and stability of the shoulders are also examined.
The patient will also be asked for the specific motion or sports that caused the pain and any medical history.
The following tests will help in confirming the diagnosis:
- X-rays to get a clear image of the bones to rule out a fracture but it can’t visualize ligaments and tendons.
- Ultrasonography – a proper ultrasound examination can detect a rotator cuff problems in the shoulder joint
- Magnetic Resonance Imaging (MRI) or MR Arthrogram is performed if a cuff tear is suspected and to get better images of the rotator cuff tendons, showing the inflammation in the Bursa and the rotator cuff. It can also detect small partial tears of the rotator cuff and also any other associated pathologies are also detected.
- Arthroscopy to look inside the shoulder joint, if it is unclear how extensive the injury is. A tiny camera is inserted into the shoulder joint to see the rotator cuff properly
