What is 'Shoulder Impingement'?

The term “Shoulder Impingement” is used frequently in medical consultations and is commonly mentioned in shoulder ultrasound reports. 

Impingement occurs when tendons and/or other structures in your shoulder are pinched between your humerus (arm bone) and acromion (bone above your shoulder) in the subacromial space (the space between the humerus and acromion).   People will often describe pain with elevating their arm, particularly half way through the movement.

                      A change in the shape of the acromion (which often occurs normally through the lifespan), can contribute to Primary Impingement.                        Image courtesy www.sportsandortho.com  

                      A change in the shape of the acromion (which often occurs normally through the lifespan), can contribute to Primary Impingement.

                       Image courtesy www.sportsandortho.com
 

The first type of impingement is called Primary Impingement.  This occurs when there is a structural abnormality in the shoulder causing narrowing of the subacromial space.  This is typically a bone spur on the acromion that causes rubbing on the underlying structures in the subacromial space, usually the rotator cuff tendons and subacromial bursa.  This will in turn lead to rotator cuff tendinosis and bursitis.

 

 

 

The following characteristics are common but not exclusive to people with primary impingement:

  • Generally older person (Greater than 35 years of age)
  • Gradual onset without an acute injury or trauma
  • Aggravated by overhead activity, particularly repetitive overhead activity
  • Will have some form of bony changes on shoulder X-ray
A close up view of the mechanisms leading to Primary Impingement                    Image courtesy www.methodistorthopaedics.com  

A close up view of the mechanisms leading to Primary Impingement

                   Image courtesy www.methodistorthopaedics.com
 

These people will initially benefit from anti-inflammatory medication and a brief period of rest from their aggravating activity.  Physiotherapy can be trialled for some symptom relief and for advice regarding proper management of the condition. If this does provide any relief a cortisone injection into the shoulder can be trialled.  If this does not help and there are noticeable bony changes found on X-ray, an arthroscopic subacromial decompression can be considered.  If this is the case for you, speak to your GP.

 

 

 

The second type of impingement is Secondary Impingement.  This occurs when there are external factors such as excessive load/activity placed on the shoulder, muscle imbalances or shoulder joint instability causing pinching of the structures in the subacromial space.  There isn’t a standardised treatment for this population because the type of treatment will depend on the underlying cause of the impingement.  Generally this population will present with abnormal shoulder postures and scapula dyskinesis (abnormal shoulder blade movement/mechanics).  A physiotherapist can assess this dyskinesis and attempt to correct the abnormal shoulder blade movement.  If this helps a patient’s symptoms then it is likely that the patient will be responsive to physiotherapy rehabilitation targeted at addressing the cause of the abnormal shoulder blade movement.  This is done by using “scapula correction techniques”.   An emphasis would also need to be placed on correcting neck, back and shoulder blade posture.

If you think you are experiencing shoulder impingement and you are not sure why, see a physiotherapist for a detailed assessment to discuss your treatment options.


Daniel Di Mauro is an APA Physiotherapist at Advance Healthcare in St Albans.  Daniel has an interest in complex spinal pain, sports injuries and dry needling. Daniel speaks fluent Italian.  The clinic is located close to Sunshine, Taylors Lakes and Keilor for your physiotherapy, pilates and Pain Management needs.