Rare entity; incidence largely unknown due to underdiagnosis

Two main types of scapular winging (▶ Fig. 20.1 ):

1. 
   

   Medial scapular winging:

   
   
   
   
   1. 
      

      Inferior pole of scapula translated medially and posteriorly off chest wall. Large scapular prominence can be seen on inspection.

   
   
2. 
   

   Lateral scapular winging:

   
   
   
   
   1. 
      

      Inferior pole of scapula depressed and laterally shifted.

Caused by a dysfunction of the stabilizing muscles of the scapula, resulting in an imbalance of forces

Serratus anterior palsy as a result of long thoracic nerve injury is most common cause of scapular winging

Clinical symptoms include upper back and shoulder pain, and difficulty with overhead motion:

1. 
   

   History of trauma could indicate acute muscular detachment.

Treatment:

1. 
   

   Management ultimately guided by etiology of winging. Typically, nonoperative management initially for neuropraxic injuries, followed by surgical treatment if nonoperative management failed. Early surgical repair for acute muscular detachments. Trapezius palsy may benefit from early nerve procedures.

Stabilizing muscles:

1. 
   

   Serratus anterior:

   
   
   
   
   1. 
      

      Originates from ribs 1–8

      
      
   2. 
      

      Responsible for scapular protraction, holding medial border of scapula against chest wall

      
      
   3. 
      

      Innervated by long thoracic nerve (C5–C7 nerve roots):

      
      
      
      
      • 
        

        i. Injury to this nerve causes serratus anterior palsy and results in medial scapular winging.

        

   
   
2. 
   

   Trapezius:

   
   
   
   
   1. 
      

      Originates from occiput and spinous processes of C7–T12

      
      
   2. 
      

      Three functional components: superior, middle, and inferior

      
      
   3. 
      

      Innervated by spinal accessory nerve.

   
   
3. 
   

   Rhomboid major and rhomboid minor:

   
   
   
   
   1. 
      

      Rhomboid major originates from T2–T5 and inserts on medial border of scapula; rhomboid minor originates from C7–T1 and inserts on medial border of scapula just superior to rhomboid major insertion

      
      
   2. 
      

      Rhomboids work together with middle portion of trapezius in scapular retraction and medial scapular border elevation

      
      
   3. 
      

      Innervated by dorsal scapular nerve.

   
   
4. 
   

   Levator scapulae:

   
   
   
   
   1. 
      

      Originates from C1–C4 transverse processes and inserts onto medial border of scapula at the level of the scapular spine

      
      
   2. 
      

      Works to elevate scapula and medially rotate its inferior angle

      
      
   3. 
      

      Innervated by C3–C4, and dorsal scapular nerve.

Nerves:

1. 
   

   Long thoracic nerve:

   
   
   
   
   1. 
      

      Innervates serratus anterior

      
      
   2. 
      

      Arises from anterior rami of C5–C7 nerve roots, running posterior to brachial plexus and axillary vessels

      
      
   3. 
      

      Susceptible to injury by direct trauma or stretch, particularly during sports participation, due to its superficial course

      
      
   4. 
      

      Can be damaged during removal of axillary lymph nodes during breast cancer surgery.

   
   
2. 
   

   Spinal accessory nerve:

   
   
   
   
   1. 
      

      Innervates trapezius and sternocleidomastoid muscles

      
      
   2. 
      

      Cranial nerve XI: Exits skull and courses downward crossing internal jugular vein before sending branches to sternocleidomastoid and trapezius muscles.