Impingement syndrome (aka Throwers shoulder) is caused by various structures including the rotator cuff tendons and bursa getting irritated as they pass through a restricted area called the subacromial space. This area located beneath the subacromial arch – the bony area above the head of the humerus (near end of the upper arm bone).  The most commonly irritated structure is the supraspinatus tendon.  The primary symptom is pain at the front/side of the shoulder as the arm is abducted (taken out to the side).

There are various causes of impingement syndrome.

• Bony abnormalities may exist within the acromial arch either congenital (born with) or abnormalities which develop as we grow older and small bony outgrowths develop
• Poor muscle balance can cause impingement.  Weakness in the serratus anterior and tightness of the pectoralis minor
• Poor scapular (shoulder blade) stabilisation allows the scapular to tip upwards during abduction of the arm thus reducing the subacromial space.
• Poor rotator cuff function.  Normally the head of the humerus should glide downwards as the shoulder is abducted due to the action of the rotator cuff muscles.  Failure of this sliding mechanism can cause the head of the humerus to jam into the acromial arch
• A rounder shoulder posture causes shoulders to internally rotate and makes impingement more likely

The condition is more common amongst individuals who perform large amounts of overhead activity with the arm due to occupation or sport e.g. tennis, swimming, throwing or decorating

Symptoms of impingement syndrome

• Painful arc of abduction.  Pain is experienced at the front and or side of the shoulder between 60 and 90 degrees of abduction of the arm
• Pain aggravated by sleeping on affected shoulder
• Pain and weakness in the supraspinatus and bideps
• Tenderness when area pressed

What you can do

• Rest with gradual return to aggravating activities
• Ice therapy

What we can do

• Reduce inflammation by using traction and distraction techniques
• Assess muscular balance/function of muscles that stabilise the scapular and provide exercises to redress imbalance
• Prescription of exercises to improve rotator cuff function
• Treatment and advice to improve posture to reduce impingement

Tags: Shoulder injury, Shoulder pain