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Shoulder

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The rotator cuff consists of four muscles that help to control the head of upper arm bone (humerus) in the socket (glenoid cavity).

Inflammation of any one of these muscles is considered rotator cuff tendonitis, which can limit motion to the shoulder joint.

Rotator cuff tendonitis is typically caused from overuse and or trauma.


A rotator cuff tear is usually described as acute or chronic, partial or full thickness. Rotator cuff tears can occur due to trauma or can result over time.

Acute ruptures are usually seen in individuals younger than 40.

Young athletes typically need surgery to repair the injured tendon, as pain and loss of motion are too debilitating for therapy.


One of the most common labral tears is called a SLAP lesion (superior labrum, anterior to posterior).

A SLAP lesion is an injury to the superior labrum and biceps tendon anchor. There are four common types of tears:

  • Type I: Degeneration and fraying of the labrum
  • Type II: Detachment of the biceps anchor
  • Type III: Bucket handle tear with intact biceps anchor
  • Type IV: A type II or III lesion that extends into the biceps tendon

Instability is also referred to as MDI (multidirectional instability).

When instability occurs, the head of the upper arm bone (humerus) can dislocate from the shoulder socket (glenoid cavity) in many directions with frequent partial dislocations.


A dislocation occurs when the head of the upper arm bone (humerus) has slipped past the socket (glenoid cavity) and is dislocated from the joint.

Most dislocations are in front of or behind the socket.

The labrum and supporting muscles have stretched passed normal range, allowing the the humerus to slide pass the edge of the socket.


A separation refers to an injury to the AC (acromioclavicular) joint. This is where the collar bone (clavicle) touches the high point of the shoulder blade (scapula).

A separation commonly occurs from a blow to the crown of the shoulder from the ground or another foreign body. There are three degrees of separations:

  • First degree: A slight tearing of AC (acromioclavicular) ligament, not to be confused with the ACL of the knee
  • Second degree: A complete tear of AC ligament, leaving intact the CC (coracoclavicular) ligament that lies beneath the AC joint
  • Third degree: A complete tear of both the AC and CC joint

Bicep tendonitis can inflame the long head of the biceps tendon as it passes under the highest point of the shoulder (acromion).

Also, an incomplete or partial dislocation of the tendon out of the bicepital groove of the upper arm bone (humerus) can predispose an individual to tendonitis.

Pain is usually localized where the biceps tendon connects to the humerus and rotation of the forearm and hand so the palm faces forward or upward will be painful.


Typically bursitis of the shoulder refers to an inflammation of the subacromial bursa due to overuse or overhead use of the shoulder.

When the subacromial space is inflamed, a rotator cuff impingement can occur, resulting in the inability to throw or function above shoulder level.


Thoracic Outlet Syndrome (TOS) refers to shoulder injuries that can cause pressure to the brachial plexus and/or subclavian artery.

TOS symptoms include paresthesia - the sensation of prickling, tingling or creeping on the skin - and coolness of the affected arm.

Individuals experiencing TOS may complain of weakness, feeling heavy or of feeling easily fatigued.


Impingement typically occurs in athletes who participate in sports with above-shoulder level action such as throwing or swimming.

Problems associated with impingement range from subacromial bursitis, rotator cuff tendonitis and possibly rotator cuff tears.

Symptoms of impingement include:

  • Pain and loss of range of motion above shoulder level
  • Decreased strength in external rotation
  • Night pain