Winging of the Scapula

Definition

Winging of the scapula refers to the abnormal protrusion of the medial border and/or inferior angle of the scapula away from the posterior thoracic wall, producing a "wing-like" appearance. The direction of winging is classified based on where the inferior angle of the scapula moves.

Anatomy & Mechanism

The scapula is held flush against the thoracic wall primarily by the serratus anterior muscle (with contributions from the trapezius and rhomboids). Paralysis of any of these muscles — usually from nerve injury — allows unopposed action of the remaining muscles to displace the scapula.

Muscle	Nerve	Root
Serratus anterior	Long thoracic nerve (nerve of Bell)	C5, C6, C7
Trapezius	Spinal accessory nerve (CN XI)	—
Rhomboids	Dorsal scapular nerve	C4, C5

Types of Winging

1. Medial Winging (more common)

Nerve injured: Long thoracic nerve (C5–C7)
Muscle paralyzed: Serratus anterior
Scapular movement: Superior elevation, scapula translated medially, inferior angle rotated medially
Elicited by: Pushing against a wall with arms outstretched ("wall push-up test") — the medial border lifts off the chest wall
Common causes: Direct trauma to lateral chest wall, sports injuries (overhead athletes, weight lifting), iatrogenic (axillary dissection, rib resection), idiopathic

2. Lateral Winging (less common)

Nerve injured: Spinal accessory nerve (CN XI)
Muscle paralyzed: Trapezius
Scapular movement: Shoulder depression, scapula translated laterally, inferior angle rotated laterally (unopposed serratus anterior pull)
Common causes: Iatrogenic — ipsilateral neck surgery (thyroidectomy, lymph node biopsy, radical neck dissection)
Additional signs: Shoulder drop, inability to shrug, difficulty abducting arm above 90°

Dorsal scapular nerve injury → rhomboid paralysis also causes lateral winging.

Mnemonics:

SWIM — Serratus Winging Is Medial TRAWL — Trapezius and Rhomboids Are Winged Laterally

Medial vs Lateral scapular winging diagram

Fig. A: Medial winging (inferior angle displaced medially). Fig. B: Lateral winging (inferior angle displaced laterally) — Miller's Review of Orthopaedics

Clinical Photo

Right-sided medial scapular winging demonstrated on the wall push-up test. The right medial scapular border protrudes prominently compared to the left.

Clinical Features

Prominent protrusion of medial border / inferior angle posteriorly
Functional deficit: Inability to fully elevate the arm (serratus anterior is essential for upward rotation of the scapula during arm elevation above 90°)
Pain around the shoulder girdle
Cosmetic deformity

Other Causes

Beyond nerve injury, winging can result from:

Osseous causes: Osteochondromas (most common bony cause), fracture malunions (e.g., clavicle malunion)
Muscle contracture (e.g., deltoid fibrosis causing abduction contracture)
Facioscapulohumeral muscular dystrophy (FSHD): winging + facial weakness + inability to whistle; normal CPK; treated with scapulothoracic fusion
Voluntary winging (can be performed voluntarily in some individuals)

Investigations

Clinical diagnosis via wall push-up test or forward arm elevation
EMG/nerve conduction studies to confirm nerve injury and localize the lesion
MRI — denervation edema of serratus anterior (hyperintense signal on PDFS sequence) in long thoracic nerve palsy

Treatment

Type	Conservative	Surgical
Medial (serratus anterior palsy)	Physiotherapy, winger's brace	Pectoralis major transfer + strip of fascia lata to scapula
Lateral (trapezius palsy)	Physiotherapy, bracing	Eden–Lange procedure — levator scapulae and rhomboids transferred laterally to spine/infraspinatus fossa of scapula

Left: Lateral winging — Eden–Lange procedure. Right: Medial winging — pectoralis major transfer with fascia lata. — Miller's Review of Orthopaedics

Most cases of long thoracic nerve palsy resolve spontaneously within 6–24 months with conservative management
Selective muscle strengthening may ameliorate winging
Surgical options indicated for unacceptable cosmetic deformity or significant functional disability

Sources:

Gray's Anatomy for Students, p. 846
Miller's Review of Orthopaedics, 9th Edition, pp. 158, 405

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