title: Anatomy and landmarks for the superior and middle cluneal nerves: application to posterior iliac crest harvest and entrapment syndromes.
abstract: OBJECTIVE
  To date, only scant descriptions of the cluneal nerves are available. As these nerves, and especially the superior group, may be encountered and injured during posterior iliac crest harvest for spinal arthrodesis procedures, the present study was performed to better elucidate their anatomy and to provide anatomical landmarks for their localization.
  
  
  METHODS
  The superior and middle cluneal nerves were dissected from their origin to termination in 20 cadaveric sides. The distance between the posterior superior iliac spine (PSIS) and superior cluneal nerves at the iliac crest and the distance between this bony prominence and the origin of the middle cluneals were measured. The specific course of each nerve was documented, and the diameter and length of all cluneal nerves were measured.
  
  
  RESULTS
  Superior and middle cluneal nerves were found on all sides. An intermediate superior cluneal nerve and lateral superior cluneal nerve were not identified on 4 and 5 sides, respectively. The superior cluneal nerves always passed through the psoas major and paraspinal muscles and traveled posterior to the quadratus lumborum. The mean diameters of the superior and middle cluneal nerves were 1.1 and 0.8 mm, respectively. From the PSIS, the superior cluneal branches passed at means of 5, 6.5, and 7.3 cm laterally on the iliac crest. At their origin, the middle cluneal nerves had mean distances of 2 cm superior to the PSIS, 0 cm from the PSIS, and 1.5 cm inferior to the PSIS. In their course, the middle cluneal nerves traversed the paraspinal muscles attaching onto the dorsal sacrum.
  
  
  CONCLUSIONS
  Knowledge of the cutaneous nerves that cross the posterior aspect of the iliac crest may assist in avoiding their injury during bone harvest. Additionally, an understanding of the anatomical pathway that these nerves take may be useful in decompressive procedures for entrapment syndromes involving the cluneal nerves.
authors.affiliation: Section of Pediatric Neurosurgery, Children's Hospital, Birmingham, Alabama 35233, USA. rstubbs@uab.edu
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Levin
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.forename: Eric A
authors.initials: EA
authors.lastname: Potts
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Cohen-Gadol
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002081:Buttocks / Q000294:innervation; D005260:Female; D006801:Humans; D007085:Ilium / Q000294:innervation; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000294:innervation; D009408:Nerve Compression Syndromes / Q000473:pathology; D012867:Skin / Q000294:innervation; D013127:Spinal Nerves / Q000033:anatomy & histology*; D020858:Tissue and Organ Harvesting