Which nerve injury would most likely cause scapular winging?

Which nerve injury would most likely cause scapular winging?

• A. Dorsal scapular nerve
• B. Spinal accessory nerve
• C. Long thoracic nerve
• D. Axillary nerve

Answer: (C)

Scapular stability hinges on keeping the shoulder blade pressed against the thorax and properly oriented for arm movement. The serratus anterior is a key stabilizer that protracts the scapula and upwardly rotates it, and it’s innervated by the long thoracic nerve. If this nerve is injured, the serratus anterior cannot hold the medial border of the scapula tight to the rib cage. The result is the classic medial winging of the scapula, especially noticeable when pushing against resistance because the scapula can no longer stay firmly anchored to the thorax. Other nerves can affect shoulder mechanics in different ways but don’t produce the same medial winging pattern. Dorsal scapular nerve injury mainly impacts rhomboids and levator scapulae, altering retraction and positioning rather than causing the winging seen with serratus anterior weakness. Spinal accessory nerve injury affects the trapezius, leading to shoulder droop and trouble with certain arm motions, not the characteristic winging. Axillary nerve injury primarily weakens the deltoid, affecting arm abduction, and does not produce the classic scapular winging.

Scapular stability hinges on keeping the shoulder blade pressed against the thorax and properly oriented for arm movement. The serratus anterior is a key stabilizer that protracts the scapula and upwardly rotates it, and it’s innervated by the long thoracic nerve. If this nerve is injured, the serratus anterior cannot hold the medial border of the scapula tight to the rib cage. The result is the classic medial winging of the scapula, especially noticeable when pushing against resistance because the scapula can no longer stay firmly anchored to the thorax.

Other nerves can affect shoulder mechanics in different ways but don’t produce the same medial winging pattern. Dorsal scapular nerve injury mainly impacts rhomboids and levator scapulae, altering retraction and positioning rather than causing the winging seen with serratus anterior weakness. Spinal accessory nerve injury affects the trapezius, leading to shoulder droop and trouble with certain arm motions, not the characteristic winging. Axillary nerve injury primarily weakens the deltoid, affecting arm abduction, and does not produce the classic scapular winging.