Thoracodorsal Nerve, Anterior View

Description

Emerging from the posterior cord of the brachial plexus, the thoracodorsal nerve (C6 to C8) descends on the posterior wall of the axilla toward the latissimus dorsi. Anteriorly, its course can be followed inferiorly and laterally as it runs in close company with the subscapular artery, typically along the vessel’s thoracodorsal continuation, while remaining deep to the axillary vein and medial to the proximal humerus. Portions of the scapula and the glenohumeral joint are visible as bony landmarks, with adjacent plexus branches arranged superior to inferior around the axillary artery region. The rib cage forms the medial background of the axillary space. A small target with a long reach. Recognizing this neurovascular pairing matters in axillary surgery because the thoracodorsal nerve is the motor supply to latissimus dorsi, and iatrogenic injury produces loss of shoulder extension, adduction, and internal rotation that patients notice when climbing, swimming, or pushing up from a chair. During axillary lymph node dissection, the nerve is sought on the undersurface of the posterior axillary fold and preserved while working near the subscapular system, and its relationship to the subscapular artery helps prevent mistaking it for a small vascular branch. The same anatomy underpins latissimus dorsi flap harvest and targeted reinnervation planning, where surgeons may intentionally identify, divide, or coapt the thoracodorsal nerve. Ideal applications include brachial plexus and axillary-region teaching in gross anatomy, surgical anatomy texts for breast and reconstructive procedures, and preoperative counseling materials that explain functional deficits after nerve injury. It also supports radiology correlation when reviewing axillary MR neurography or ultrasound landmarks around the posterior cord and subscapular vessels. Anatomical accuracy verified by SciePro's Medical Advisory Board.