Innervation of the female levator ani muscles

Matthew D. Barber, Ronald E. Bremer, Karl B. Thor, Paul C. Dolber, Thomas J. Kuehl, Kimberly W. Coates

Research output: Contribution to journalArticle

144 Citations (Scopus)

Abstract

OBJECTIVE: The objective of this study was to characterize the innervation of the human female levator ani muscles. STUDY DESIGN: Detailed dissections of the peripheral innervation of the iliococcygeal, pubococcygeal, puborectal, and coccygeal muscles were performed in 12 fresh-frozen female cadavers (aged, 32-100 years) with the use of transabdominal, gluteal, and perineal approaches. Both the pudendal nerve and the sacral nerve roots that enter the pelvis from the cephalic side were followed from their origin at the sacral foramina to their termination. Pelvic floor innervation was described with reference to fixed bony landmarks, particularly the coccyx, the ischial spine and the inferior pubis. Photographs were taken, and nerve biopsies were performed to confirm the gross findings histologically. Biopsy specimens were stained with Masson's trichrome. RESULTS: In each dissection, a nerve originated from the S3 to S5 foramina (S4 alone, 30%; from S3 and S4, 40%; from S4 and S5, 30%), crossed the superior surface of the coccygeal muscle (3.0 ± 1.4 cm medial to the ischial spine [range, 1.0-4.2 cm]), traveled on the superior surface of the iliococcygeal muscle innervating it at its approximate midpoint, and continued on to innervate both the pubococcygeal and puborectal muscles at their approximate midpoint. The pudendal nerve originated from the S2 to S4 foramina, exited the pelvis through the greater sciatic foramen, traversed Alcock's canal, and branched to innervate the external anal sphincter, the external urethral sphincter, the perineal musculature, the clitoris, and the skin. Despite specific attempts to locate pudendal branches to the levator ani, none could be demonstrated. Nerve biopsy specimens that were obtained at gross dissection were confirmed histologically. CONCLUSION: Gross dissections suggest that the female levator ani muscle is not innervated by the pudendal nerve but rather by innervation that originates the sacral nerve roots (S3-S5) that travels on the superior surface of the pelvic floor (levator ani nerve). Because definitive studies (eg, nerve transection or neurotracer studies) cannot be performed in humans, further studies that will use appropriate animal models are necessary to confirm and extend our findings.

Original languageEnglish (US)
Pages (from-to)64-71
Number of pages8
JournalAmerican Journal of Obstetrics and Gynecology
Volume187
Issue number1
DOIs
StatePublished - 2002
Externally publishedYes

Fingerprint

Anal Canal
Pudendal Nerve
Muscles
Dissection
Pelvic Floor
Pelvis
Biopsy
Spine
Coccyx
Pubic Bone
Clitoris
Urethra
Cadaver
Animal Models
Head
Skin

Keywords

  • Levator ani muscle
  • Pelvic floor
  • Pudendal nerve

ASJC Scopus subject areas

  • Medicine(all)
  • Obstetrics and Gynecology

Cite this

Barber, M. D., Bremer, R. E., Thor, K. B., Dolber, P. C., Kuehl, T. J., & Coates, K. W. (2002). Innervation of the female levator ani muscles. American Journal of Obstetrics and Gynecology, 187(1), 64-71. https://doi.org/10.1067/mob.2002.124844

Innervation of the female levator ani muscles. / Barber, Matthew D.; Bremer, Ronald E.; Thor, Karl B.; Dolber, Paul C.; Kuehl, Thomas J.; Coates, Kimberly W.

In: American Journal of Obstetrics and Gynecology, Vol. 187, No. 1, 2002, p. 64-71.

Research output: Contribution to journalArticle

Barber, MD, Bremer, RE, Thor, KB, Dolber, PC, Kuehl, TJ & Coates, KW 2002, 'Innervation of the female levator ani muscles', American Journal of Obstetrics and Gynecology, vol. 187, no. 1, pp. 64-71. https://doi.org/10.1067/mob.2002.124844
Barber MD, Bremer RE, Thor KB, Dolber PC, Kuehl TJ, Coates KW. Innervation of the female levator ani muscles. American Journal of Obstetrics and Gynecology. 2002;187(1):64-71. https://doi.org/10.1067/mob.2002.124844
Barber, Matthew D. ; Bremer, Ronald E. ; Thor, Karl B. ; Dolber, Paul C. ; Kuehl, Thomas J. ; Coates, Kimberly W. / Innervation of the female levator ani muscles. In: American Journal of Obstetrics and Gynecology. 2002 ; Vol. 187, No. 1. pp. 64-71.
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