Intercostal Nerve Motor and Sensory Branch Trajectories: A Morphometric Study with Applications for Intercostal Nerve Transfers

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 365–376

DOI: 10.46882/2026/IJAP/000198

Article Type: Original Research Article

Title: Intercostal Nerve Motor and Sensory Branch Trajectories: A Morphometric Study with Applications for Intercostal Nerve Transfers

Names of Authors: Jean-Pierre Girard¹, Michel L. Dubois²

Authors’ Affiliations: ¹Laboratory of Anatomy, Faculty of Medicine, University of Paris, Paris, France; ²Department of Plastic, Reconstructive and Aesthetic Surgery, Hôpital Européen Georges-Pompidou, Paris, France

Abstract:
Intercostal nerve (ICN) transfers are frequently utilized in neurotization procedures to restore function following brachial plexus avulsion injuries. This study evaluated the internal topography, axon count estimates, and specific branching points of the fourth, fifth, and sixth ICNs to define optimal surgical parameters. Dissections were performed on thirty sides of fifteen adult human cadavers. The point of origin of the lateral cutaneous branch (LCB, primarily sensory) relative to the mid-axillary line was recorded, and the remaining anterior trunk (primarily motor) was traced to its insertion into the musculus rectus abdominis or intercostal spaces. The LCB originated at an average distance of 14.2 ± 1.8 mm posterior to the mid-axillary line across all examined ribs. Proximal to the LCB origin, the main ICN trunk possessed a mean diameter of 2.14 ± 0.18 mm. Distal to the LCB bifurcation, the motor-dominant anterior trunk retained a diameter of 1.42 ± 0.12 mm, containing an estimated mean fascicle area optimized for coaptation. The total length of the harvestable anterior motor trunk from the mid-axillary line to the parasternal border averaged 16.5 ± 1.4 cm. These morphometric findings confirm that the anterior trunk of the 4th–6th ICNs provides adequate length and size match for direct neurotization of the musculocutaneous nerve, minimizing the need for nerve grafts.

Keywords: Intercostal Nerve, Brachial Plexus, Nerve Transfer, Neurotization, Morphometry, Cadaveric Dissection

Manuscript Timeline: Received: August 05, 2026; Revised: September 09, 2026; Accepted: September 20, 2026; Published: September 30, 2026

Citation: Girard J.P., & Dubois M.L. (2026). Intercostal Nerve Motor and Sensory Branch Trajectories: A Morphometric Study with Applications for Intercostal Nerve Transfers. International Journal of Anatomy and Physiology, 15(9), 365–376. DOI: 10.46882/2026/IJAP/000198

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