summary Scapular winging is a dysfunction involving the stabilizing muscles of the scapula resulting in imbalance and abnormal motion of the scapula. Diagnosis is made clinically with the presence of excessive medializing scapular retraction (medial winging) or excessive lateralizing scapular protraction (lateral winging). Treatment is generally observation, physical therapy and activity modification or operative depending on etiology of winging and presence of identifiable neurological lesion. Epidemiology Anatomic location Types of scapular winging defined by the direction of the superomedial corner of the scapula medial scapular winging etiology dysfunction of the serratus anterior (long thoracic nerve) weak protraction of the scapula excessive medializing scapular retraction (rhomboid major and minor) and elevation (trapezius) innervated by C5, C6 and C7 epidemiology young athletic patient more common than lateral lateral scapular winging etiology dysfunction of the trapezius (cranial nerve XI - spinal accessory nerve) weak superior and medializing force on the scapula excessive lateralizing scapular protraction (serratus anterior, pectoralis major and minor) epidemiology usually iatrogenic (history of neck surgery) Anatomy Scapulothoracic articulation not a true joint attached to thorax via ligaments at the acromioclavicular (AC) joint suction mechanism created by serratus anterior and subscapularis holds scapula closely to thorax allows scapular movement against the posterior rib cage contributes to glenohumeral joint positioning and mechanics Stabilizing muscles scapula serves as attachment site for 17 muscles function to stabilize scapula to the thorax, provide power to the upper limb and synchronize glenohumeral motion serratus anterior originates from ribs 1-8 and inserts on anteromedial border of scapula total 7-10 slips primary motion is scapular protraction (anterior and lateral motion) innervated by long thoracic nerve ventral rami of C5, C6, C7 blood supply superiorly: long thoracic artery inferiorly: thoracodorsal artery branches three parts with different functions upper: downward rotation (glenoid down), stabilizes superior scapula middle: scapular protraction lower: upward rotation and abduction trapezius originates from medial third superior nuchal line, external occipital protuberance, nuchal ligament and C7-T12 spinous processes inserts on lateral third clavicle, acromion and scapular spine primary motion is upward rotation and elevation of the scapula innervated by spinal accessory nerve cranial nerve XI three parts with different functions upper: upward rotation and elevation middle: scapular retraction and adduction lower: downward rotation and depression rhomboid major and rhomboid minor rhomboid major originates from T2-T5 spinous processes and inserts onto medial scapular border, just below insertion of rhomboid minor rhomboid minor originates from C7 and T1 spinous processes and inserts onto medial scapular border, near base of scapular spine primary motion is scapular retraction innervated by dorsal scapular nerve levator scapulae originates from C1-C4 transverse processes and inserts onto medial border of scapula at the level of the scapular spine primary motion is elevation of the scapula and downward rotation to tilt the glenoid cavity inferiorly innervated by C3-C4 cervical plexus with contributions from dorsal scapular nerve Nerves long thoracic nerve arises from ventral rami of C5, C6 and C7 anatomic variations C4 contribution in 13% absence of C7 contribution in 8% travels posterior to the axillary vessels and brachial plexus runs superficially to the serratus anterior, giving branches to each slip crow's foot point where the long thoracic nerve intersects the most dominant and inferior serratus branch of the thoracodorsal artery spinal accessory nerve (cranial nerve XI) spinal and cranial portions join to form the accessory trunk accessory trunk traverses the jugular foramen, crosses laterally over the internal jugular vein to innervate the sternocleidomastoid enters posterior triangle of the neck to innervate the trapezius Medial Scapular Winging Pathophysiology deficit in serratus anterior function due to injury to the muscle itself or to the long thoracic nerve mechanical traumatic avulsion of the serratus anterior displaced fractures of the inferior pole of the scapula neurologic traction nerve injury > 50% of the cases repetitive stretch injury is most common gradual onset of weakness and winging increased risk with head tilted away during overhead arm activity, repetitive throwing, prolonged abduction weight lifters, volleyball players can be acute injury with immediate winging in cases of high-energy trauma (motorcycle accident) compressive nerve injury acute blunt trauma to the chest wall, head or neck (contact sports, motor vehicle accidents) sudden depression of the shoulder girdle (fall) chronic sites of compression scalene muscles subcoracoid between coracoid and 1st or 2nd rib (carrying heavy objects on shoulder) inflamed bursae (subcoracoid, subscapular, accessory and supracoracoid) anteroinferior scapular border direct nerve injury iatrogenic 10% of patients had prior surgery radical mastectomy / axillary lymph node dissection thoracic surgery chest tube placement for pneumothorax penetrating injury to chest wall neuralgic amyotrophy (brachial neuritis) presents with isolated unilateral palsy of the long thoracic nerve in 22% consider in patients without clear traumatic onset and with antecedent immunological insult and/or inflammatory response Presentation vague, nonspecific shoulder girdle pain and fatigue base of neck, scapula and deltoid muscle spasms weakness when lifting away from body and overhead activity discomfort sitting against a chair may have neurologic symptoms due to traction on brachial plexus subjective shoulder instability failure of the scapula to provide a stable platform for rotation of the glenohumeral joint Evaluation physical examination inferior medial scapula elevates and protrudes posteriorly and medially worsened by forward arm flexion abduction often limited to 90° or less weakness of forward arm flexion and abduction wasting of anterior scalene triangle due to atrophy of the sternocleidomastoid muscle scapular compression test physician actively applies an anterior force on the posterior scapula with one hand while stabilizing the anterior chest wall with the other hand and having the patient perform forward flexion. the test is positive if the patient has greater motion of the affected side during shoulder flexion compared to when the physician applies no scapular force diagnostic studies electromyography helps assess involvement of long thoracic nerve versus a mechanical cause of winging (serratus anterior avulsion) Treatment nonoperative observation, physical therapy and activity modification indications observe for a minimum of 6 months, ideally 18 months to 2 years wait for nerve to recover technique physical therapy for serratus anterior strengthening, stretching avoid painful or heavy lifting activities bracing with a modified thoracolumbar brace can be considered poor compliance and little benefit outcomes majority of patients will spontaneously resolve with full return of shoulder function and resolution of winging by 2 years operative early repair of serratus anterior avulsion indications mechanical disruption of the serratus anterior muscle (avulsion) and/or its insertion (inferior pole scapula fractures) with symptomatic winging should undergo surgical repair acutely neurolysis of the long thoracic nerve indications failure to improve with conservative treatment, at least 6 months electromyography with signs of nerve compression (distal latency, dennervation) technique supraclavicular decompression as the nerve traverses the scalene muscles outcomes excellent improvement in pain and resolution of winging in patients who failed nonoperative management (98%) better improvement in shoulder strength (flexion and abduction) compared to muscle transfers muscle transfer: split pectoralis major transfer indications failure to improve with conservative treatment, for 1-2 years pain relief and improved shoulder function with manual scapular stabilization technique split pectoralis major transfer (sternal head) direct transfer can be performed with tendon origin off the humerus with or without a bone block can use interposed tendon allograft or autograft (hamstring) if not enough excursion to perform a direct transfer. most effective outcomes predictor of successful surgery is symptom relief and improved function with preoperative manual scapular stabilization often have persistent shoulder abduction weakness complications failure of pectoralis muscle transfer attachment at scapula unsatisfactory cosmesis (breast asymmetry in women) infection adhesive capsulitis nerve transfer developing area in the microsurgical field technique lateral branch of the thoracodorsal nerve to the long thoracic nerve medial pectoral nerve with sural nerve graft to the long thoracic nerve outcomes shown to successfully reinnervate the long thoracic nerve benefit of preserving proper muscle biomechanics scapulothoracic fusion indications scapular winging from diffuse neuromuscular disorders failed muscle transfer surgery often not the first surgical treatment of choice primary goal is pain relief technique fusion of the anterior scapula to the posterior rib cage, with wire cables and/or plates and screws outcomes limited increase in shoulder motion ~20° gain of abduction recent studies show high satisfaction levels in 82% of patients at 5-year follow up complications nonunion pleural effusion adhesive capsulitis symptomatic hardware requiring removal Lateral Scapular Winging Pathophysiology deficit in trapezius function due to injury to the spinal accessory nerve (CN XI) neurologic iatrogenic most common vulnerable in the posterior triangle of the neck cervical lymph node biopsy radical neck dissection traumatic traction injury sudden lateral flexion of the neck (motor vehicle or motorcycle accidents) blunt trauma deep tissue massage penetrating injury to the neck Presentation similar to medial scapular winging vague, nonspecific shoulder girdle pain and fatigue muscle spasms weakness with overhead activity discomfort sitting against a chair may have neurologic symptoms from traction on the brachial plexus subjective shoulder instability failure of the scapula to provide a stable platform for rotation of the glenohumeral joint shoulder impingement inferior translation of the coracoacromial arch as scapula depresses secondary to loss of trapezius Evaluation physical examination superior medial scapula drops downward and protrudes posterior and lateral worsened by arm abduction and resisted external rotation shoulder girdle appears depressed or drooping asymmetry or visible atrophy of the ipsilateral trapezius weakness of forward arm flexion and abduction scapular stabilization manual stabilization of the scapula often improves pain diagnostic studies electromyography helps distinguish isolated spinal accessory nerve injury from other more extensive neurologic injuries Treatment nonoperative observation, physical therapy and activity modification indications the role of conservative management is controversial given that most injuries are iatrogenic direct nerve injuries and warrant surgical intervention elderly and sedentary patients and those without an identifiable injury should be initially treated conservatively outcomes predictors of a poor outcome with conservative management include inability to raise the arm above the shoulder at presentation and dominant extremity involvement operative exploration of the spinal accessory nerve, neurolysis, repair indications identifiable nerve injury diagnosed early technique should be performed within 20 months of injury muscle transfer: levator scapulae, rhomboid major and rhomboid minor indications nerve injury diagnosed late (> 20 months from injury) technique Eden-Lange transfer: transfer of the levator scapulae (LS) to the lateral scapular spine, along with transfer of the rhomboid minor (Rm) and rhomboid major (RM) to the infraspinatus fossa Triple Tendon Transfer: a variant of the Eden-Lange where the LS and rhomboid muscles are all transferred to the scapular spine (Rm most medial, then RM, then LS most lateral) to reconstruct the trapezius scapulothoracic fusion see above under Medial Scapular Winging