Thoracodorsal nerve

The thoracodorsal nerve, also known as the middle or long subscapular nerve, originates from the posterior cord of the brachial plexus, receiving fibers primarily from the C7 nerve root, with contributions from C6 and C8. This purely motor nerve branches off the posterior cord in the axilla and descends vertically along the posterior axillary wall, accompanied by the subscapular artery (a branch of the axillary artery).

The primary function of the thoracodorsal nerve is to innervate the latissimus dorsi, a large muscle of the posterior axillary wall responsible for extending, adducting, and internally rotating the arm. The nerve continues its descent alongside the thoracodorsal artery and vein, which are further terminal branches of the subscapular vessels.