What is the clinical significance of the long thoracic nerve?

The long thoracic nerve plays a crucial role in the movement and stability of the scapula, particularly by innervating the serratus anterior muscle. When the long thoracic nerve is injured, it can lead to a condition known as winged scapula. This occurs because the serratus anterior muscle is essential for protraction of the scapula and for holding it against the thoracic wall. An injury to this nerve impairs the function of the serratus anterior, causing the scapula to protrude away from the back, resembling a wing-like appearance. This condition can significantly affect shoulder mechanics and the overall stability of the shoulder girdle, resulting in difficulties with arm movements.

The other choices do not accurately reflect the function or implications of the long thoracic nerve. It does not innervate the biceps, nor does it control the shoulder joint directly. Additionally, dismissing its significance as having “no clinical significance” overlooks the important functional impairments that arise from injury to this nerve, underscoring its value in clinical assessments of shoulder and scapular function.