It is derived from their ventral rami (in spite of the fact that the latissimus dorsi is found in the back) of cervical nerves C6-C8.

It penetrates into the substance of the latissimus dorsi muscle near the lateral border of scapula.

[citation needed] The thoracodorsal nerve innervates the latissimus dorsi muscle on its deep surface.

[6] Posterior cord lesions can result in the loss of adduction of the shoulder joint, as innervation to latissimus dorsi is lost.

[3] This article incorporates text in the public domain from page 934 of the 20th edition of Gray's Anatomy (1918)