<P> The serratus anterior is innervated by the long thoracic nerve (Nerve of Bell), a branch of the brachial plexus . The long thoracic nerve travels inferiorly on the surface of the serratus . The nerve is especially vulnerable during certain types of surgery (for example, during lymph node clearance from the axilla (e.g., in case of axillary dissection in a surgery for breast cancer)). Damage to this nerve can lead to a winged scapula . </P> <P> All three parts described above pull the scapula forward around the thorax, which is essential for anteversion of the arm . As such, the muscle is an antagonist to the rhomboids . However, when the inferior and superior parts act together, they keep the scapula pressed against the thorax together with the rhomboids and therefore these parts also act as synergists to the rhomboids . The inferior part can pull the lower end of the scapula laterally and forward and thus rotates the scapula to make elevation of the arm possible . Additionally, all three parts can lift the ribs when the shoulder girdle is fixed, and thus assist in respiration . </P> <P> The serratus anterior is occasionally called the "big swing muscle" or "boxer's muscle" because it is largely responsible for the protraction of the scapula--that is, the pulling of the scapula forward and around the rib cage that occurs when someone throws a punch . </P> <P> The serratus anterior also plays an important role in the upward rotation of the scapula, such as when lifting a weight overhead . It performs this in sync with the upper and lower fibers of the trapezius . </P>

The boxer muscle is known in medical terms as