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Shoulder Impingement

What is it ? 

Shoulder Impingement is a condition that is caused by a tendon or bursa rubbing against the shoulder blade.

Anatomy and overview:


The shoulder is made up of two joints (acromioclavicular and glenohumeral joint), which are made up of three main bones, the
humerus (the upper arm) the scapula (shoulder blade), and the clavicle. The acromioclavicular joint is where part of the scapula and the clavicle meet. The glenohumeral joint, commonly referred to as a ball and socket joint, is where the humeral head(ball) and the glenoid (the socket) meet. In addition to the joint there is a fluid filled sac (bursa) cushions the shoulder joint, preventing friction in the socket. Impingement occurs when the shoulder’s bursa and/or rotator cuff tendons are intermittently trapped and compressed while raising the shoulder.

Probable cause

During normal shoulder function, there should not be an impact between the acromion process and the soft bursa or rotator cuff tendons below.  However, muscle weakness can lead to abnormal movement patterns in your shoulder leading to impingement. Repetitive improper use (overuse) of the muscles may also cause inflammation, which decreases the space between the humeral head and acromion. Poor posture can also lead to improper movement patterns of the shoulder, causing increased inflammation. 

Common Symptoms

The main symptom of shoulder impingement is sudden pain towards the top of your shoulder when you lift your arm overhead or backward. Other symptoms may include: 

  • Pain or clicking when putting your hand behind your back or head.
  • Muscle weakness when attempting to reach or lift
  • Pain when lying on the sore shoulder.
  • Pain reaching for the seat-belt or across your chest.
  • Pain that goes from the front of your shoulder to the side of your arm
  • General stiffness and throbbing when shoulder is at rest

Physical Therapy Treatment:

Shoulder impingement typically responds well to physical therapy. In physical therapy they may use gentle exercises to rebuild strength and range of motion. Your physical therapy sessions can help to improve the function of your rotator cuff, improve posture and correct movement patterns. If you work in a field that requires heavy lifting, perform regular workout routines or you are an athlete that requires frequent use of your shoulder, your physical therapist can teach you proper techniques to reduce your chance of recurrence.