American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the main consequence of injury to the long thoracic nerve?

1. Winged scapula

2. Drop arm syndrome

3. Rotator cuff tear

4. Torticollis

The correct answer is: Winged scapula

Injury to the long thoracic nerve predominantly results in winged scapula. This condition arises when the nerve is compromised, leading to dysfunction of the serratus anterior muscle, which plays a crucial role in stabilizing the scapula against the thoracic wall. When this muscle is weak or paralyzed due to nerve injury, the scapula protrudes away from the thorax, creating the characteristic "winged" appearance, especially during arm movements. While other conditions like drop arm syndrome, rotator cuff tears, and torticollis involve shoulder and neck dysfunction, they are caused by different mechanisms. For instance, drop arm syndrome is typically associated with rotator cuff injury, and torticollis results from muscular or neurological issues affecting the neck. Thus, the prominent clinical manifestation of long thoracic nerve injury clearly correlates to the presentation of a winged scapula. Understanding this connection is vital for diagnosing nerve injuries and addressing shoulder dysfunction.