Thoracodorsal nerve

The thoracodorsal nerve also known as the middle subscapular or long subscapular nerve arises from the posterior cord of the brachial plexus and supplies the latissimus dorsi muscle.

Gross anatomy

Origin

The thoracodorsal nerve arises from the posterior cord of the brachial plexus with fibres from the sixth, seventh and eighth cervical nerves.

Course

After branching from the brachial plexus the thoracodorsal nerve runs down the posterior axillary wall. At its origin it is posterior to the subscapular artery however as it descends along the posterior wall of the axilla it comes to lie in front of the artery, which at this level is called the thoracodorsal artery. 

The thoracodorsal nerve crosses the lower border of the teres major muscle and enters the deep surface of the latissimus dorsi with terminal branches of the nerve extending to the inferior border of the muscle.

Branches and Supplysupply

• Thethe thoracodorsal nerve supplies the latissimus dorsi muscle.

Relations

The thoracodorsal nerve is closely related to the subscapular artery and its branch the thoracodorsal artery. Initially the thoracodorsal nerve lies behind the subscapular artery but as it descends comes to lie anterior to the thoracodorsal artery.

Variant anatomy

The thoracodorsal nerve may arise from the axillary nerve or from a common trunk with the upper and lower subscapular nerve in a small proportion of the population.

Related pathology

The thoracodorsal nerve may be damaged in surgical procedures of the lower axilla. The nerve supply is preserved in surgical flaps involving the latissimus dorsi and occasionally the nerve is harvest and grafted for facial nerve reconstruction.