Variations in the Branching and Trajectory of the Lateral Femoral Cutaneous Nerve: A High-Resolution Ultrasound study

International Journal of Anatomy and Physiology | Vol. 15, No. 9, September 2026 | pp. 341–352

DOI: 10.46882/2026/IJAP/000196

Article Type: Original Research Article

Title: Variations in the Branching and Trajectory of the Lateral Femoral Cutaneous Nerve: A High-Resolution Ultrasound study

Names of Authors: Min-Jun Park¹, Ji-Young Choi²

Authors’ Affiliations: ¹Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, South Korea; ²Department of Physical Medicine and Rehabilitation, Asan Medical Center, Seoul, South Korea

Abstract:
The lateral femoral cutaneous nerve (LFCN) is prone to entrapment at the inguinal ligament, leading to meralgia paresthetica, and is at risk during anterior hip arthroplasties. This study used high-resolution ultrasound (HRUS) to determine the anatomical path and variations of the LFCN relative to the anterior superior iliac spine (ASIS). One hundred limbs from fifty healthy adult volunteers were scanned with an 18-MHz linear array transducer. The distance from the LFCN to the medial edge of the ASIS at the inguinal level was measured, and its branching variations were recorded. The mean distance from the ASIS to the main LFCN trunk was 12.4 ± 2.5 mm medially. Three structural variants were identified based on the nerve's crossing relative to the inguinal ligament: Type A (medial to ASIS, crossing superficial to the sartorius muscle) in 74.0%, Type B (crossing directly over the ASIS) in 14.0%, and Type C (running deep through the sartorius muscle or tensor fasciae latae tendon) in 12.0% of limbs. Bifurcation into anterior and posterior branches occurred above the inguinal ligament in 18.0% of cases. These HRUS data demonstrate high positional variability of the LFCN, highlighting the value of pre-procedural ultrasound mapping to prevent accidental nerve transection during regional blocks and surgical incisions.

Keywords: Lateral Femoral Cutaneous Nerve, High-Resolution Ultrasound, Meralgia Paresthetica, Anterior Superior Iliac Spine, Inguinal Ligament

Manuscript Timeline: Received: August 01, 2026; Revised: September 06, 2026; Accepted: September 18, 2026; Published: September 30, 2026

Citation: Park M.J., & Choi J.Y. (2026). Variations in the Branching and Trajectory of the Lateral Femoral Cutaneous Nerve: A High-Resolution Ultrasound study. International Journal of Anatomy and Physiology, 15(9), 341–352. DOI: 10.46882/2026/IJAP/000196

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