Thoracodorsal Nerve

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

Keywords

Thoracodorsal nerve, Middle subscapular nerve

AKA

• Thoracodorsal Nerve
• Middle Subscapular Nerve

Origin

The Thoracodorsal nerve branches from the Posterior Cord and originates from C6, C6, C7, & C8 nerve roots¹.

Path

1. The Thoracodorsal nerve comes off the Posterior Cord¹
2. Travels along the posterior–lateral chest wall^1,2
3. Along the surface of the serratus anterior¹
4. Dives deep to the subscapularis muscle¹
5. Finally giving rise to branches that innervate the latissimus dorsi¹

Anatomy

“The nerve runs along the posterior axillary wall to reach and innervate the deep surface of the latissimus dorsi muscle. This muscle (along with the teres major) adducts and internally rotates the arm and depresses the raised arm. It is best tested by having the patient adduct the horizontally raised upper arm against resistance or by palpating the muscle bellies when the patient coughs [409].”²

Innervation

• Lats

Motor Innervation

Thoracodorsal n. Direct Muscle Innervations
Muscle	Origin	Insertion	Innervation	Action

Lesion

“Lesions of this nerve usually occur with damage to the posterior cord or proximal parts of the brachial plexus. Nerve lesions cause little deformity or atrophy, but proximal arm adduction is compromised. A combined movement comprising extension, adduction, and internal rotation, in which the dorsum of the hand is placed on the opposite buttock, readily reveals latissimus paresis. Isolated thoracodorsal nerve injury has been described in body builders [47,262].”²

References

1.

Dutton M. Dutton’s Orthopaedic Examination, Evaluation, and Intervention. 5th ed. McGraw Hill Education; 2020.

2.

Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 8th ed. Wolters Kluwer Health; 2022.