**Core Concept**
The "winging" of the scapula refers to the abnormal protrusion of the scapula's lateral border, resulting from weakness or paralysis of the muscles that stabilize it against the thoracic wall. This condition is often associated with damage to the long thoracic nerve, which supplies the serratus anterior muscle.

**Why the Correct Answer is Right**
The serratus anterior muscle plays a crucial role in stabilizing the scapula against the thoracic wall, particularly during movements such as forward elevation of the arm. Injury to the long thoracic nerve can lead to denervation of the serratus anterior muscle, resulting in weakness and subsequent winging of the scapula. This is because the serratus anterior muscle helps to pull the scapula downward and medially, preventing it from protruding outward.

**Why Each Wrong Option is Incorrect**
**Option A:** Injury to the suprascapular nerve, which supplies the supraspinatus and infraspinatus muscles, would not directly cause winging of the scapula, as these muscles primarily control abduction and rotation of the arm.
**Option B:** Damage to the thoracodorsal nerve, which supplies the latissimus dorsi muscle, would result in weakness of arm adduction, but not winging of the scapula.
**Option C:** Injury to the axillary nerve, which supplies the deltoid and teres minor muscles, would primarily affect arm abduction and external rotation, rather than scapular stabilization.

**Clinical Pearl / High-Yield Fact**
Winging of the scapula is often a sign of underlying nerve damage, particularly to the long thoracic nerve. A thorough neurological examination, including assessment of muscle strength and tone, is essential in diagnosing this condition.

**Correct Answer:** C. Injury to the long thoracic nerve.