Clinical Anatomy of the Superior Cluneal Nerve in Relation to Easily Identifiable Bony Landmarks

Abstract

Background: Lower back pain (LBP) remains a common ailment among adult populations and a superior cluneal nerve (SCN) entrapment accounts for 10% of reported LBP cases. The diagnostic criteria for SCN entrapment include anaesthesia of the area supplied by the SCN after performing a nerve block. Several surgical reports describe the anatomy of the SCN but purely anatomical studies of the course of the SCN are rare. This study aimed to describe the location of the SCN in relation to easily identifiable bony landmarks.

Methods: The SCN was identified as it pierced the thoracolumbar fascia and crossed over the posterior part of the iliac crest on both sides of 27 adult cadavers. A sliding dial calliper was used to measure the distance from the posterior superior iliac spine (PSIS) to the SCN and from the midline lumbar spinous processes to the nerve.

Results: The PSIS to SCN measurement was found to be 69.6 ± 15.0 mm (mean ± SD) while the midline to SCN measurement was 72.1 ± 10.2 mm.

Discussion: This study showed clear gender differences in the PSIS to SCN measurement, due to the sexual dimorphism of the bony pelvis. There was also found to be a positive correlation between the height of the sample and the distances of the SCN from both the midline and PSIS. This study provides a clear anatomical description of the course of the SCN as it crosses the iliac crest, which will allow for the successful identification of the SCN.

Keywords: Bone Harvesting, Entrapment Syndrome, Lower Back Pain, Regional Nerve Block, Superior Cluneal Nerve