Abstract
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 placements of stimulation devices to engage targeted functions while avoiding off-target effects. However, no quantified map of how vagal branches emerge and how they relate 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 (2.33 ± 2.80 cm) and below the left carotid bifurcation (2.58 ± 3.17 cm). Alternate placement regions separating targeted organs from off-targets: sympathetic vs. cervical visceral at 6/8 cm (L/R), cardiac vs. carotid sinus/bifurcation at 14/10 cm, and recurrent laryngeal vs. other cervical visceral at 18/13 cm from JF. Overall, no differences were found between male and female donors.
Conclusions
This study provides a quantified, landmark-registered map of cervical and thoracic vagal branch emergence, offering a standardized anatomical template that may inform strategies for more function-selective vagal neuromodulation.
Full Text Availability
The license terms selected by the author(s) for this preprint version do not permit archiving in PMC. The full text is available from the preprint server.
