Ventrolateral view, left thoracic region

The thoracodorsal nerve is also called the third subscapular nerve.  It serves the latissimus dorsi muscle.  We will find it on the deep side of the latissimus dorsi at its humeral end running with the thoracodorsal artery.  There are actually three subscapular nerves.  The upper and lower subscapular nerves both innervate the subscapularis muscle.  The lower subscapular nerve also innervates the teres major muscle.  All of these subscapular nerves are lateral branches of the posterior cord of the brachial plexus.