Review Question - QID 109203

This patient is presenting with a repeat injury (likely secondary to weight lifting) and a physical exam finding of a winged scapula. This finding occurs secondary to injury to the long thoracic nerve.

The long thoracic nerve innervates the serratus anterior muscle which functions to keep the scapula pressed against the thorax. It is commonly injured by repeat trauma (such as reaching overhead to clean/paint or sports such as weight lifting) or surgery. When injured, the key physical exam finding is a winged scapula which appears as an elevation of the scapula off the rib cage (Figure A). Treatment for this condition is rest and avoidance of the exacerbating activity.

Figure A demonstrates a winged scapula on physical exam.

Incorrect Answers:
Answer 2: The thoracodorsal nerve innervates the lattismus dorsi and is not commonly injured. Injury to this nerve would not result in a winged scapula.

Answer 3: The axillary nerve innervates the deltoid. Injury to this nerve presents with a loss of sensation over the deltoid and weakness of the deltoid muscle.

Answer 4: The suprascapular nerve innervates the supraspinatus and infraspinatus muscle which are involved in abduction of the arm. An injury to this nerve would not produce a winged scapula.

Answer 5: The dorsal scapular nerve innervates the rhomboids which pulls the scapula medially and works to keep it pressed against the rib cage. This nerve is much less likely to be injured by repeat trauma when compared to the long thoracic nerve.

Bullet Summary:
The long thoracic nerve innervates the serratus anterior muscle and when injured can result in a winged scapula.