Winging of the Scapula

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Definition

Winging of the scapula refers to abnormal prominence of the medial or lateral border of the scapula away from the thoracic wall due to muscular imbalance or nerve injury affecting scapular stabilizers.

Causes of Medial Winging of the Scapula

Most common cause:
Paralysis or weakness of the serratus anterior muscle due to injury of the long thoracic nerve.
Loss of serratus anterior function prevents proper fixation of the scapula to the thoracic cage, leading to medial border prominence.

Course of the Long Thoracic Nerve

Arises from the ventral rami of C5, C6, and C7 nerve roots.
Passes through the cervico-axillary canal.
Courses between the clavicle and the first rib.
Descends vertically along the lateral chest wall.
Supplies motor innervation to the serratus anterior muscle throughout its length.

Functional Anatomy of Serratus Anterior

Origin: Upper 8–9 ribs
Insertion: Anterior surface of the medial border of the scapula
Function:
- Anchors the scapula to the rib cage
- Facilitates scapular protraction and upward rotation
- Essential for overhead elevation of the arm

Important Anatomical Note

The scapula is the largest bone of the shoulder complex and serves as the attachment site for numerous muscles.
Although these muscles may act synergistically or antagonistically, they function in a highly coordinated manner to ensure smooth and efficient shoulder motion.

Mechanisms of Long Thoracic Nerve Injury

The long thoracic nerve is particularly vulnerable due to its long and superficial course and may be injured by:

Trauma (direct blow, traction injuries)
Sustained pressure (surgical positioning, carrying heavy loads)
Neuritis or inflammatory conditions

Signs and Symptoms of Long Thoracic Nerve Injury

Medial winging of the scapula
Shoulder or periscapular pain
Weakness of shoulder elevation
Difficulty elevating the arm above shoulder level
Muscle spasm of pericapsular muscles attempting to compensate
Visible cosmetic deformity, especially during pushing activities

Clinical Evaluation Tests

1. Wall Push Test

The patient stands facing a wall approximately two feet away.
Asked to push against the wall with both palms placed flat at waist or shoulder level.
Positive test: Prominent medial border of the scapula indicates serratus anterior weakness.

2. Resisted Forward Flexion Test

The patient forward flexes both arms.
The examiner applies downward resistance.
Exaggeration of scapular winging suggests long thoracic nerve dysfunction.

Management

Non-Operative Treatment

Observation for a minimum of 18 months, allowing time for spontaneous nerve recovery.
Magnetic Resonance Imaging (MRI) to identify compressive or structural lesions.
Electromyography (EMG) and muscle testing to assess nerve function.
Physiotherapy focusing on:
- Serratus anterior strengthening
- Scapular stabilization exercises

Operative Treatment

Pectoralis major muscle transfer
Indicated in persistent, symptomatic cases with no evidence of nerve recovery after adequate conservative management.

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