Anatomical Relationship of the Deep Branch of the Ulnar Nerve to the Hook of Hamate: A High-Resolution Morphometric Cadaveric Study

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 221–232

DOI: 10.46882/2026/IJAP/000186

Article Type: Original Research Article

Title: Anatomical Relationship of the Deep Branch of the Ulnar Nerve to the Hook of Hamate: A High-Resolution Morphometric Cadaveric Study

Names of Authors: Pierre-Yves Dupont¹, Jean-Luc Moreau²

Authors’ Affiliations: ¹Laboratory of Anatomy, Faculty of Medicine, University of Lille, Lille, France; ²Department of Hand Surgery, University Hospital Center of Lille, Lille, France

Abstract:
Compression of the deep branch of the ulnar nerve (DBUN) within Guyon’s canal leads to isolated motor deficits, commonly resulting from hook of hamate fractures or ganglion cysts. This study established precise morphometric measurements of the DBUN’s pathway relative to the hook of hamate to optimize surgical safety zones. Fifty formaline-fixed human cadaveric hands (25 left, 25 right) were carefully dissected under magnification. The shortest distance from the radial border of the hook of hamate to the main trunk of the DBUN was determined using a digital caliper. The branching sequence to the hypothenar muscles, interossei, and musculus adductor pollicis was recorded. The DBUN orbited around the distal tip of the hook of hamate at an average distance of 3.4 ± 0.6 mm. In 76.0% of specimens, the nerve gave off its primary motor branch to the musculus opponens digiti minimi before crossing the hook, while in 24.0% the branching occurred directly adjacent to the hook. The mean diameter of the DBUN trunk at the hamate level was 1.82 ± 0.21 mm. No significant differences were found between left and right hands (p > 0.05). These quantitative parameters map a narrow iatrogenic danger zone, providing hand surgeons with specific boundaries to protect the ulnar motor trunk during hook excision or tunnel release.

Keywords: Ulnar Nerve, Guyon's Canal, Hook of Hamate, Morphometry, Hand Anatomy, Entrapment Neuropathy

Manuscript Timeline: Received: July 11, 2026; Revised: August 20, 2026; Accepted: September 03, 2026; Published: September 18, 2026

Citation: Dupont P.Y., & Moreau J.L. (2026). Anatomical Relationship of the Deep Branch of the Ulnar Nerve to the Hook of Hamate: A High-Resolution Morphometric Cadaveric Study. International Journal of Anatomy and Physiology, 15(9), 221–232. DOI: 10.46882/2026/IJAP/000186

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