Winged scapula: causes, symptoms, tests and treatment

The scapula, or shoulder blade, is a flat triangular bone on the back of the ribcage. It sits against the ribs and glides as you move your arm. A private UK shoulder clinic explains that it has more muscles attached to it than any other bone in the shoulder, and that each muscle works together so that the arm can move in different directions.

In winging, the inner border of the shoulder blade lifts away from the chest wall, so it looks like a wing, particularly when you reach forwards or push. The BMJ Case Reports article describes scapular winging as an uncommon but potentially disabling condition that can affect the ability to lift, pull and push heavy objects and to perform everyday activities such as brushing teeth. The shoulder clinic, by contrast, says winging is actually very common but is often overlooked because it often causes no pain or other symptoms. Sources therefore differ on how common it is, depending on how mild cases are counted.

It can be a problem in its own right or a sign of another condition, so careful assessment matters.

The article explains that stability of the scapula depends mainly on two muscles, the serratus anterior and the trapezius, so dysfunction of either, and more commonly the serratus anterior, can cause winging. The serratus anterior is supplied only by the long thoracic nerve, which has a long and superficial course and is therefore susceptible to injury.

Most injuries of the long thoracic nerve are neuropraxias, meaning the nerve is temporarily stunned rather than cut, and are caused by trauma such as a blow to the chest wall or a sudden depression of the shoulder girdle in a fall. Overuse of the shoulder and strenuous exercise have also been implicated, and the article notes that it is more commonly reported in young athletes.

Other causes grouped by the article include damage to the spinal accessory nerve leading to trapezius palsy, muscle disorders such as facioscapulohumeral muscular dystrophy, bone problems such as scoliosis, and joint problems such as severe contractures. The shoulder clinic adds that inflammation of the nerve, for example brachial neuritis (Parsonage-Turner syndrome), can cause it, as can repeated shoulder dislocations or compensating for pain elsewhere in the shoulder by holding the shoulder in an unnatural posture.

The shoulder clinic says the symptoms that accompany winging vary according to the cause and that some people seem to have none. Others have pain or weakness in the shoulder, arm or neck. The BMJ article lists pain, weakness, limitation of shoulder elevation and winging of the scapula in people with serratus anterior palsy.

• A shoulder blade that sticks out, usually on one side.

• Pain or aching around the shoulder blade, shoulder or neck.

• Weakness or difficulty lifting the arm, particularly above shoulder height.

• Difficulty pushing, pulling or lifting heavy objects.

• Difficulty shrugging the shoulders, if the trapezius is involved.

The article says the diagnosis of long thoracic nerve injury is largely clinical. The doctor or physiotherapist examines the shoulder, assesses movement and may ask you to push against a wall, which makes the winging more prominent. Examination of the cervical spine is important to rule out neck disease.

Plain X-rays of the cervical spine, chest and shoulder help to rule out structural abnormalities or bone disease, and MRI or CT scans are helpful in specific cases, for example a disc herniation or when a tumour is suspected. EMG and nerve conduction studies are very helpful to confirm serratus anterior muscle palsy and long thoracic nerve injury, according to the article. The shoulder clinic notes that in most cases X-ray is normal because the majority of cases are due to soft tissue problems.

The article says that all patients with scapular winging should be referred for orthopaedic evaluation, which in the NHS usually means an assessment through a GP or musculoskeletal service.

Both sources describe physiotherapy as the first approach. The shoulder clinic says most problems associated with a winging scapula can be solved with physiotherapy, which involves strengthening weakened muscles and retraining dysfunctional muscles to work properly, with an exercise programme designed for the individual. The article says various braces and orthotic devices are of doubtful benefit and cumbersome to wear.

Time is part of the treatment for nerve-related winging. The article says most acute serratus anterior palsy resolves spontaneously by 6 to 9 months and at most by 2 years, and that serratus anterior paralysis and winging will persist in approximately 25 per cent of patients treated conservatively, who are candidates for surgery. Surgical options described include transferring a muscle, such as the sternal head of pectoralis major, to the lower angle of the scapula, and, more recently, nerve decompression or nerve transfer, which has shown early promising results.

The shoulder clinic notes that surgery may also be needed to remove a lesion pressing on a nerve, to stabilise the shoulder joint or to transfer tendons, and that physiotherapy follows surgery.

While the nerve recovers, it can help to avoid heavy lifting or overhead work that provokes pain, to keep the shoulder moving within comfortable limits and to follow your physiotherapist's exercises rather than forcing the arm. The BMJ article records a child who still had winging 2 years after injury and pain on swimming, which illustrates that recovery is not always complete.

See a GP if a shoulder blade starts to stick out, particularly after an injury, illness, surgery or a period of unusual activity, and sooner if you have significant pain, weakness or loss of movement. Sudden weakness with severe pain, or new numbness or weakness in the arm or legs, needs prompt medical assessment.

On the NHS, care typically starts with a GP or, in many areas, a self-referral to a community musculoskeletal physiotherapy service, with orthopaedic or neurology referral and nerve studies if the winging persists or the cause is unclear. Many people never need more than physiotherapy.

Private shoulder specialists and physiotherapists are available for those who want faster assessment. Nerve studies and surgery are carried out by a small number of specialist centres, so it is reasonable to ask what the clinician expects to find, how long you should wait before considering surgery and which tests are needed.