Causes Of A Winged Scapula
In most cases of winged scapula that we see in our Randwick and Sydney physio practices, the serratus anterior muscle is the main culprit. The serratus anterior muscle attaches to the medial (inside) border of the shoulder blade and sweeps across the side of the shoulder blade between the shoulder blade and the ribs before insertion into the lateral aspect to the ribcage. When working as intended the serratus anterior anchors the scapula against the rib cage when at rest, throughout movement and when the upper limbs take load, fixing the scapula snugly up against the chest wall . When serratus anterior contracts, it works to help cause upward rotation, abduction, and elevation of the shoulder blade movements which assist in allowing your arm to be raised above your head. Basically it pulls the shoulder blade up and around the chest wall, assisting in keeping the ball and the socket lined up as the arm moves outwards and upwards.
Weakness of serratus anterior causes the scapula to slip away from being tucked up against the rib cage, and the inside border of the scapula fans out giving it the wing-like appearance on the upper back, known as winged scapula. Weakness of serratus anterior can occur as the result of damage or impingement to the nerve that innervates the muscle. The long thoracic nerve is the motor nerve to the serratus anterior muscle and is suggested to be prone to injury due to the long and superficial path it travels. Damage to this nerve has a number of potential causes being of both traumatic (for example, following a dislocated shoulder) and non traumatic origin (such as following viral infection).
Other than damage to the nerve supplying serratus anterior, some suggested potential causes of a winged scapula include:
- Brachial plexus injury
- Shoulder instability
- Palsy or weakness of other stabilizing muscles of the scapula
- Rotator cuff pathology
Diagnosing A Winged Scapula
Presentation of a winged scapula may be quite subtle and more challenging to pick up, or be blatantly obvious and relatively easy to diagnose with the naked eye. Even when obvious and the scapula is protruding out and visibly winging, this does not however tell you “why” the shoulder blade is winging. Physical examination and at times the use of investigations such as: standard x-rays, MRI of the shoulder, neck, or scapula as well as electromyography (EMG) testing of affected nerves and muscles may be performed to isolate the exact nerve/s and muscle/s involved. Understanding which muscles and nerves are involved and uncovering the underlying cause of the winging is vital when looking to address the scapula dysfunction and create a tailored rehabilitation plan.
Winging Scapular At Sydney Physio Clinic
In our Sydney physio practice it is common to see scapular dyskinesis, a condition where the shoulder blade moves abnormally. This condition is usually due to muscle imbalances causing the altered scapulohumeral rhythm. Scapular dyskinesis may be caused through a number of factors including:
- Poor posture
- Shoulder injury
- Overuse of the shoulders in employment, hobbies, or sports
- Injury to the muscles of the scapular
- Rotator cuff pathology
- Pain in the shoulder
Scapular dyskinesis is usually responsive to physiotherapy treatment that works to address muscle imbalances and the underlying causes of the abnormal movement pattern of the shoulder blade. Noting that as mentioned above pain can cause altered movement patterns causing scapular dyskinesis and physiotherapy treatment that assists in relieving pain in some circumstances will see any compensatory movements of the shoulder blade resolve. A weak serratus anterior and subsequently some mild winging of the scapula is a common feature with abnormal scapulohumeral rhythm and physiotherapists would often prescribe some targeted serratus anterior strengthening exercises to improve the control and strength of the muscle if assessed as being weak. However, true scapular winging as a result of nerve damage to the long thoracic nerve or other nerve palsy’s are both more visually striking and functionally disabling. Fortunately nerve injury is far less common than adaptive weakness and as a result this type of winging scapula presents more inconsistently to our Randwick or CBD physio clinics.
Disclaimer: Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance on Serratus Anterior And A Winged Scapula should consult his or her general practitioner, sports medicine specialist, physiotherapist or otherwise appropriately skilled practitioner.