A standardized, surgically relevant map for emergence of organ-specific branches from the human vagus nerve

Introduction. Vagus nerve stimulation modulates laryngeal, cardiac, pulmonary, and gastrointestinal functions. Knowledge of where along the vagal trunk organ-specific branches emerge may support alternative surgical placement of stimulation devices to engage targeted functions while avoiding off-target effects. However, no quantified map of emergence of vagal branches and their relationship to surgically relevant anatomical landmarks exists in humans.

Methods. Fifty-eight vagus nerves (29 left, 29 right) from 29 embalmed donor bodies (15 females) were dissected from the jugular foramen through the thoracic cavity. Branches were traced to end organs and allocated to seven groups — sympathetic, muscular, vascular, cardiac, pulmonary, esophageal, and multiple targets — and several sub-groups. Distances between branch emergence and the jugular foramen (JF) were normalized to three anatomical landmarks: carotid bifurcation, laryngeal prominence, and superior border of clavicle.

Results. Branch emergence follows a proximal-to-distal order: sympathetic (5.28 cm from JF), muscular (9.59 cm), vascular (10.70 cm), cardiac (19.65 cm), pulmonary (25.36 cm), and esophageal (26.57 cm). Vagal branches emerge into two embryological domains separated near the clavicle: pharyngeal arch-targeting branches cluster proximally (9.34 cm) and primitive mediastinum-targeting branches cluster distally (23.74 cm), with sympathetic, muscular, and vascular sub-groups occupying distinct zones within the proximal domain. The largest branch-free intervals occur above the left clavicle (length 2.33 ± 2.80 cm) and below the left carotid bifurcation (2.58 ± 3.17 cm). Targeted branches are maximally separated from off-target branches at specific distances: sympathetic vs. cervical muscular/vascular at 6 or 8 cm (L/R), cardiac vs. carotid sinus at 14/10 cm, and recurrent laryngeal vs. other cervical muscular at 18/13 cm. Overall, no differences were found between male and female donors.

Conclusions. This study provides a quantified, landmark-registered map for cervical and thoracic vagal branch emergence, offering an anatomical template that may inform strategies for more function-selective vagal neuromodulation.