The primary function of the long thoracic nerve is to provide motor innervation to the serratus anterior muscle, which is instrumental in the protraction and upward rotation of the scapula. This muscle allows the arm to be raised above shoulder level by stabilizing the scapula against the rib cage during arm movements. Optimal functioning of the long thoracic nerve is essential for various actions such as reaching overhead, pushing, and other upper limb activities. Furthermore, the serratus anterior plays a notable role in maintaining proper shoulder girdle alignment, which is crucial for preventing injuries and ensuring fluid movement of the arm. The interplay between the long thoracic nerve and the serratus anterior is fundamental not only for athletic performance but also for daily activities that require lifting or reaching.
The long thoracic nerve courses down the lateral aspect of the thorax before reaching its target, the serratus anterior muscle. It runs along the surface of the upper and middle portions of the serratus anterior, lying just beneath the skin and often in close proximity to the ribs. This nerve can be particularly vulnerable to injury in certain positions, especially when the arm is elevated, as its path runs close to the ribs. Anatomically, it travels from the spinal cord down through the neck and axilla, making it an intricate component of the brachial plexus, and it is strategically positioned to facilitate its important role in shoulder stability and function.