Winged Scapula (Scapula Alata)

Essentials

• Possible paresis of the serratus anterior muscle should be kept in mind in association with shoulder injury and surgery in the chest area.
• Injury to the accessory nerve in association with a surgical intervention should be readily recognized and repaired.

Aetiology

• Paresis of the serratus anterior muscle due to lesion of the long thoracic nerve. The nerve is most commonly damaged by shoulder injuries involving a sudden jerk downwards, exceptionally heavy loading (e.g. carrying), surgical interventions (e.g. breast cancer surgery), stretching performed under anaesthesia or by neuritis.
• The trapezius muscle may become paralyzed when the accessory nerve is damaged in association with lymph node resection, biopsy or surgical interventions to the neck, or when it gets compressed by a suture or a scar.

Symptoms

• Pain in the shoulder and scapular region, which may radiate to the upper extremity
• In serratus paresis the pain may also be located on the thorax and in the axilla.
• Lifting of the arm over the horizontal level is impeded, and when lifting the arm, the scapula will protrude (winged scapula, scapula alata).
• Later on, pain on movement of the shoulder will develop due to instability of the scapula.

Diagnosis

• In paresis of the serratus anterior muscle, the winging of the scapula is observed in resisted forward lift of the arm and when the patient pushes against a wall with both hands (note asymmetry between the two sides!); pictures 1 2.
• In paresis of the accessory nerve (picture 3) the scapula is winged especially in resisted abduction of the arm, and the whole shoulder drops several centimetres downwards due to muscle atrophy (asymmetry!).
• The neck, axillae and chest are palpated to detect a possible tumour.
• Chest x-ray is taken if needed.
• The diagnosis is confirmed by ENMG.

Treatment