Scapular Winging

Written by: Dr Jeremy Steinberg – created: 19 August 2021; last modified: 14 June 2025

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Scapular Winging
Synonym	Winged scapula,
Pathophysiology	The condition results from an imbalance of the force couples that stabilize the scapula, typically due to weakness in the serratus anterior or trapezius muscles.
Classification	Winging is classified as medial or lateral based on the direction of scapular movement, and by its etiology (nerve, muscle, bone, joint) according to the Fiddian classification.
Clinical Features	Shoulder pain, fatigue, weakness with overhead activities, and a visible protrusion of the scapula that is enhanced by specific movements.
Tests	Electromyography (EMG) and nerve conduction studies (NCS), while MRI can help rule out structural causes.
Treatment	Primarily non-operative with observation and physical therapy, though surgery such as nerve repair or muscle transfers may be considered for persistent cases.

Scapular winging is a dysfunction involving the stabilizing muscles of the scapula, resulting in imbalance, abnormal motion, and a prominence of the medial or vertebral border of the scapula. This may or may not be symptomatic.

Diagnosis is made clinically with the presence of excessive medializing scapular retraction (medial winging) or excessive lateralizing scapular protraction (lateral winging). The most common cause is long thoracic nerve palsy leading to serratus anterior weakness, often due to neuralgic amyotrophy. The second most common cause is spinal accessory nerve palsy causing trapezius weakness, which is frequently overlooked.

Treatment is generally observation, physical therapy, and activity modification. Operative intervention may be considered depending on the etiology of the winging and the presence of an identifiable neurological lesion.

Classification

Medial vs Lateral Scapular Winging

Winging is defined by the direction of the superomedial corner of the scapula. However there are changes in the entire scapula position, not just this area.

Medial winging is caused by a deficit in serratus anterior function, due to injury to the muscle itself or to the Long Thoracic Nerve. This manifests as weak protraction of the scapula, with excessive medialising scapular retraction (from unopposed rhomboids) and excessive elevation (from the unopposed trapezius). It is more common than lateral winging and is typically seen in young, athletic patients.

Lateral winging is caused by a deficit in Trapezius function due to injury to the Spinal Accessory Nerve (cranial nerve XI). This manifests as a weak superior and medialising force on the scapula, resulting in excessive lateralizing scapular protraction (from unopposed serratus anterior and pectoralis major/minor). It is most commonly iatrogenic, with patients often having a history of neck surgery

A much rarer cause of lateral winging is dorsal scapular nerve injury causing a deficit in Rhomboid function. It is thought to most commonly be caused by entrapment beneath a hypertrophic middle scalene muscle.

Fiddian Classification

Fiddian et al. provided a useful classification scheme, especially in the absence of a clear long thoracic or spinal accessory nerve palsy.

• Type I: Nerve - long thoracic nerve palsy and spinal accessory nerve palsy
• Type II: Muscle - congenital absence of serratus anterior and/or trapezius, traumatic avulsion, facioscapulohumeral dystrophy, fibrosis of deltoid
• Type III: Bone - scoliosis, craniocleidodysostosis, osteochondromata, malunion of clavicle/acromion fractures.
• Type IV: Joint - abduction/internal rotation contractures, avascular necrosis of the humerus, chronic posterior shoulder dislocation
• Voluntary: A fifth category where other causes are excluded in bilateral dynamic winging.

Static vs Dynamic

• Static winging is due to a fixed deformity of the shoulder girdle, spine or ribs. It is usually present at rest.
• Dynamic winging is due to a neuromuscular disorder, visible with active and resisted movements, and absent at rest.

Aetiology and Pathophysiology

A study of 128 patients with unilateral winged scapula (both medial and lateral winging) identified the causes as:

• Long thoracic nerve palsy (54%) (87% from neuralgic amyotrophy)
• Spinal accessory nerve palsy (30%)
• Both nerve palsies (4%)
• Facioscapulohumeral dystrophy (4%)
• Orthopaedic causes (9%)
• Voluntary (5%)
• No definitive cause (2%)

Orthopaedic causes of medial winging include traumatic avulsion of the serratus anterior muscle, displaced fractures of the inferior pole of the scapula, traction injury, and compression injury. Traction is a common cause often from repetitive stretch (e.g., weightlifting, volleyball, overhead activities) leading to a gradual onset. It can also be an acute, high-energy trauma (e.g., motorcycle accident). Compression can be acute (blunt trauma to chest/neck, sudden shoulder depression) or chronic (compression at the scalene muscles, subcoracoid space, or from carrying heavy objects).

A study of 54 patients with spinal accessory nerve palsy (lateral winging) found that 65% had a medical origin and 35% had a surgical origin.

• Neuralgic amyotrophy (22 cases).
• Facioscapulohumeral dystrophy (4 cases, but accounted for 44.4% of those under 25).
• Idiopathic (5 cases),
• Post-radiation (2 cases)
• Abnormal loop of jugular vein (1 case)
• Basilar impression (1 case).
• Cervical lymph node biopsy (8 cases).
• Other regional neck surgeries (6 cases)
• Selective neck dissection (2 cases)
• Cervicofacial lift (2 cases)
• Traumatic neck wound (1 case).

Within the neuromuscular diseases, facioscapulohumeral dystrophy is the most common causes but there are other rarer diseases to consider.

Neuromuscular disorders associated with scapular winging

Often
Facioscapulohumeral muscular dystrophy Scapuloperoneal syndromes Limb-girdle muscular dystrophy
Occasional
Emery-Dreifuss syndrome Polymyositis Inclusion body myositis Acid maltase deficiency Mitochondrial myopathy Desmin storage myopathy Nemaline myopathy Centronuclear myopathy McArdle’s disease

Relevant Anatomy

The scapula serves as an attachment site for 17 different muscles, functioning to stabilize the scapula to the thorax, provide power to the upper limb, and synchronize glenohumeral motion.

Scapulothoracic Articulation

This is not a true joint. The scapula is held to the thorax by a suction mechanism created by the serratus anterior and subscapularis. This allows for scapular movement against the posterior ribcage, which is critical for proper glenohumeral positioning and mechanics.

Key Stabilizing Muscles

Key Muscles in Scapular Stabilization

Muscle	Origin	Insertion	Primary Action	Innervation
Serratus Anterior	Ribs 1-8	Anteromedial border of scapula	Scapular protraction	Long Thoracic Nerve (C5, C6, C7)
Trapezius	Medial superior nuchal line, EOP, nuchal ligament, C7-T12 spinous processes	Lateral clavicle, acromion, scapular spine	Upward rotation, elevation	Spinal Accessory Nerve (CN XI)
Rhomboid Major/Minor	Major: T2-T5 spinous processes Minor: C7-T1 spinous processes	Medial scapular border	Scapular retraction	Dorsal Scapular Nerve
Levator Scapulae	C1-C4 transverse processes	Medial border of scapula at the level of the spine	Elevation, downward rotation	C3-C4 cervical plexus, Dorsal Scapular Nerve

Key Nerves

• Long Thoracic Nerve: Arises from ventral rami of C5, C6, and C7. It travels posterior to the axillary vessels and runs superficially on the serratus anterior, innervating each slip.
• Spinal Accessory Nerve (CN XI): Exits the jugular foramen, innervates the sternocleidomastoid, then enters the posterior triangle of the neck to innervate the trapezius.

Clinical Features

Neuralgic amyotrophy is a common underlying cause and the clinician should be familiar with its presentation. Consider this with a non-traumatic onset, especially with a preceding immunological or inflammatory event. This is an acute painful monophasic neuropathy with unique or multiple nerve lesions. Clinical features are weakness, amyotrophy, and sensory loss in an asymmetric and patchy distribution, mainly involving the upper limbs. Cervical MRI is normal.

Medial Winging (Serratus Anterior) Presentation

Symptoms: Vague, non-specific shoulder girdle pain and fatigue (neck, scapula, deltoid), muscle spasms, weakness with lifting away from the body and overhead activity, discomfort sitting against a chair, and possible subjective shoulder instability.

Physical Exam: The inferior medial scapula elevates and protrudes posteriorly and medially. This is worsened by forward arm flexion (e.g., wall push-up test). Abduction is often limited to 90 degrees or less. Manual stabilisation of the scapula often improves pain and increases flexion and abduction. Include formal muscle testing.

Lateral Winging (Trapezius) Presentation

Symptoms: Similar to medial winging, with vague pain, fatigue, and weakness. May also have shoulder impingement from inferior translation of the coracoacromial arch as the scapula depresses.

Physical Exam: The superior medial scapula drops downward and protrudes posteriorly and laterally. This is worsened by arm abduction and resisted external rotation. The shoulder girdle appears depressed or "drooping." There may be asymmetry or visible atrophy of the trapezius. Manual stabilisation of the scapula often improves pain. Include formal muscle testing.

Patients are frequently misdiagnosed, the correct diagnosis only being proposed by the referring physician in 5.7% of medical cases, and 58% of surgical cases. As patients struggle to abduct greater than 90 degrees in the coronal plane they may be misdiagnosed with rotator cuff pathology.

Differential Diagnosis

Differentiating Serratus Anterior vs Trapezius Patterns

Clinical patterns for differentiating between long thoracic nerve and spinal accessory nerve palsies

	Long Thoracic Nerve Palsy  (Serratus Anterior) - Medial	Spinal Accessory Nerve Palsy (Trapezius) - Lateral
SCAPULA AND SHOULDER POSITION
Position of scapula superomedial border	Medial translocation	Lateral translocation and depression. Inferior margin also more lateral.
Scapular winging at rest	Mild	Prominent
Shoulder sagging at rest	Subtle	Obvious
Neck line	Normal	Asymmetry due to upper trapezius fibre loss
MUSCLES
Serratus anterior	Atrophied	May be seen
Upper trapezius	May be seen	Atrophied
Lower trapezius	Rope-like lower trapezius, can be raised by the medial margin of scapula during anterior elevation.	Atrophied
Levator scapulae at rest	Not visible	Prominent (with chronic weakness only)
Rhomboid major	Never seen (masked by normal trapezius).	Rope-like. Can be seen rising from the inferior angle of the scapula towards the upper thoracic vertebrae.
MOVEMENT
Movement that enhances winging	Forward flexion (wall push-up), protraction against resistance	Abduction especially with external rotation against resistance
Dynamic sign	Nil	During shoulder abduction there is an abrupt sliding of the scapula laterally and downwards ("catching up")
Triangle sign	Negative	Positive (compensatory spinal hyperextension with forward flexion in prone, because there is lack of acromion elevation)
Active elevation lag sign	Negative	Positive (compensatory spinal hyperextension with forward flexion in standing, because there is lack of acromion elevation)

Scapula positions with movement. Modified from Seror et al.
Left: right LTN showing a medial pattern of winging with forward flexion while pushing against a wall. Arrow shows ropelike lower trapezius running obliquely towards the lower thoracic vertebrae, meaning the SAN is competent. Red arrow shows absent pull of serratus anterior due to LTN palsy.
Right: right SAN palsy showing a lateral pattern of winging during abduction. Red arrows show absent pull of trapezius due to SAN palsy.

Scapula positions at rest.
Left: Long thoracic nerve palsy. Note medial translocation, milder winging, and minimal depression of shoulder
Right: Spinal accessory nerve palsy. Note the lateral translocation of the scapula, striking winging, droopy shoulder, and prominent levator scapulae Modified from  Liveson JA, Spieholz B. Peripheral neurology. Case studies in electrodiagnosis.

Investigations

Definitive diagnosis requires electrophysiology (EMG/NCS). These studies help confirm the diagnosis, assess the involvement of the nerve versus a mechanical cause (e.g., serratus avulsion), and distinguish isolated nerve injury from more extensive neurologic issues.

Plain films may be useful for identifying bone abnormalities as per Fiddian type III (e.g. osteochondromas, malunited fractures, scoliosis).

MRI of the cervical spine and/or brachial plexus may be required rule out structural causes of nerve compression (e.g., disc herniation, tumors, thoracic outlet syndrome). It can also show muscle oedema in acute denervation or fatty atrophy in chronic cases.

High-resolution ultrasound can be used to visualise the nerves (like the long thoracic nerve) and assess muscle morphology. It can be a dynamic and cost-effective adjunct to EMG. This is highly operator dependent.

Treatment

Non-Operative Management

This is the first line of treatment for most nerve-related cases. Observation is usually the first step - wait for nerve recovery, typically observing for a minimum of 6-18 months, and up to 2 years. The majority of patients with long thoracic nerve palsy resolve spontaneously. Physical Therapy may have a role, focus on strengthening the affected muscle (e.g., serratus anterior) and periscapular muscles, along with stretching. Activity Modification advice - avoid painful or heavy lifting activities. modified thoracolumbar brace can be considered, but compliance is often poor with little benefit.

Operative Management for Medial Winging (Serratus Palsy)

• Early Repair of Serratus Anterior Avulsion: Indicated for acute mechanical disruption of the muscle.
• Neurolysis of the Long Thoracic Nerve: Indicated after failure of conservative treatment (>6 months) with EMG signs of nerve compression. Involves supraclavicular decompression.
• Split Pectoralis Major Transfer: The most common transfer. Indicated after failure of conservative treatment (1-2 years). Success is predicted by pain relief and improved function with preoperative manual scapular stabilization.
• Nerve Transfer: A developing technique, for example transferring the thoracodorsal nerve to the long thoracic nerve, which has the benefit of preserving muscle biomechanics.
• Scapulothoracic Fusion: A salvage procedure for failed muscle transfers or winging from diffuse neuromuscular disorders. The primary goal is pain relief.

Operative Management for Lateral Winging (Trapezius Palsy)

The role of conservative management is more controversial given that many injuries are iatrogenic. Predictors of a poor outcome with non-operative treatment include the inability to raise the arm above the shoulder at presentation.

• Exploration, Neurolysis, and Repair of Spinal Accessory Nerve: Indicated for identifiable nerve injuries diagnosed early (ideally within 20 months).
• Eden-Lange Muscle Transfer: Indicated when the nerve injury is diagnosed late (>20 months). It involves transferring the levator scapulae and rhomboid muscles from the medial border to the lateral border of the scapula to reconstruct trapezius function.
• Scapulothoracic Fusion: Same indications as for medial winging; a salvage procedure.

Resources

Scapular Winging - Members Subpage

Literature Review

Literature Review

Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf

Articles from all years: PubMed search, Google Scholar search.

TRIP Database: clinical publications about evidence-based medicine.

Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,