The Long Thoracic Nerve (external respiratory nerve of Bell; posterior thoracic nerve) supplies the Serratus anterior.

It usually arises by three roots from the fifth, sixth, and seventh cervical nerves; but the root from the seventh nerve may be absent.

The roots from the fifth and sixth nerves pierce the Scalenus medius, while that from the seventh passes in front of the muscle.

The nerve descends behind the brachial plexus and the axillary vessels, resting on the outer surface of the Serratus anterior.

It extends along the side of the thorax to the lower border of that muscle, supplying filaments to each of its digitations.

Damage

Clinically

Due to its long, relatively superficial course, it is susceptible to injury either through direct trauma or stretch.

Injury has been reported in almost all sports.

Symptoms are often minimal – if symptomatic, a posterior shoulder or scapular burning type of pain may be reported.

A lesion of the nerve paralyses the wall to produce scapula winging, which is most prominent when the arm is lifted forward or when the pt. pushes the outstretched arm against a wall However, even winging may not be evident until the trapezius stretches enough to reveal an injury several weeks prior

External links

Peripheral nervous system | Back anatomy

Nervus thoracicus longus