Anatomic Study of Superior Cluneal Nerves: Revisiting the Contribution of Lumbar Spinal Nerves.

Abstract

Superior cluneal nerve (SCN) entrapment neuropathy can result in low back pain and thus be confused with other pathologies (e.g., lumbar disk disease). Therefore we performed cadaveric dissection of the SCN to better understand its anatomy and segmental origin. Twenty sides from 10 Caucasian fresh frozen cadavers (6 females and 4 males) were used in this study. The diameter of the SCN, distance between the exit point of the SCN from the thoracolumbar fascia and midline, and distance between the exit point of the SCN from the thoracolumbar fascia and the posterior superior iliac spine to the medial and lateral SCN were measured. The segmental origins of the SCNs were verified. Seventy-five percent of the dorsal rami of L1, 90% of L2, 95% of L3, 45% of L4, and 10% of L5 contributed to the SCN. The SCN was formed by 3 vertebral levels in 55% and by 4 vertebral levels in 30%. Three SCNs pierced the thoracolumbar fascia in 45%. The origin of the SCN, which has been described in the textbook and literature for a long time, should be reconsidered on the basis of our study results.