Anatomical study of superior cluneal nerves: Revisiting the contribution of the lumbar spinal nerves.

OBJECTIVE: Superior cluneal nerve entrapment neuropathy might cause pseudosciatica with various symptoms. We performed cadaveric dissection of the SCN to reveal the anatomy of the SCN including its segmental origin. METHODS: Twenty sides from ten (six females and four males) Caucasian fresh frozen cadavers were used in this study. The diameter of the SCN, distance between the exit point of the SCN from the fascia and the midline and distance between the exit point of the SCN from the fascia and the posterior superior iliac spine of the medial and lateral SCN were measured. RESULTS: The segmental origin of the SCNs were verified. RESULTS: 75% 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 three vertebral levels in 55% and by four vertebral levels in 30%. The number of the SCN piercing the thoracolumbar fascia was three in 45%. CONCLUSIONS: These results support the idea that the SCN might become entrapped in the thoracolumbar fascia