Innervation of the pelvic floor muscles: a reappraisal for the levator ani nerve.
OBJECTIVE
We investigated the clinical anatomy of the levator ani nerve and its topographical relationship with the pudendal nerve.


METHODS
Ten female pelves were dissected and a pudendal nerve blockade was simulated. The course of the levator ani nerve and pudendal nerve was described quantitatively. The anatomical data were verified using (immuno-)histochemically stained sections of human fetal pelves.


RESULTS
The levator ani nerve approaches the pelvic-floor muscles on their visceral side. Near the ischial spine, the levator ani nerve and the pudendal nerve lie above and below the levator ani muscle, respectively, at a distance of approximately 6 mm from each other. The median distance between the levator ani nerve and the point of entry of the pudendal blockade needle into the levator ani muscle was only 5 mm.


CONCLUSIONS
The levator ani nerve and the pudendal nerve are so close at the level of the ischial spine that a transvaginal "pudendal nerve blockade" would, in all probability, block both nerves simultaneously. The clinical anatomy of the levator ani nerve is such that it is prone to damage during complicated vaginal childbirth and surgical interventions.
Wallner
Christian
C
Department of Anatomy & Embryology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
Maas
Cornelis P
CP
Dabhoiwala
Noshir F
NF
Lamers
Wouter H
WH
DeRuiter
Marco C
MC
D002102:Cadaver; D005260:Female; D006801:Humans; D007001:Hypogastric Plexus / Q000033:anatomy & histology*; D007150:Immunohistochemistry; D018482:Muscle, Skeletal / Q000294:innervation*; D009407:Nerve Block / Q000592:standards; D017773:Pelvic Floor / Q000033:anatomy & histology* / Q000294:innervation*