title: Innervation of the levator ani muscles: description of the nerve branches to the pubococcygeus, iliococcygeus, and puborectalis muscles.
abstract: We described the innervation of the levator ani muscles (LAM) in human female cadavers. Detailed pelvic dissections of the pubococcygeus (PCM), iliococcygeus (ICM), and puborectalis muscles (PRM) were performed on 17 formaldehyde-fixed cadavers. The pudendal nerve and the sacral nerves entering the pelvis were traced thoroughly, and nerve branches innervating the LAM were documented. Histological analysis of nerve branches entering the LAM confirmed myelinated nerve tissue. LAM were innervated by the pudendal nerve branches, perineal nerve, and inferior rectal nerve (IRN) in 15 (88.2%) and 6 (35.3%) cadavers, respectively, and by the direct sacral nerves S3 and/or S4 in 12 cadavers (70.6%). A variant IRN, independent of the pudendal nerve, was found to innervate the LAM in seven (41.2%) cadavers. The PCM and the PRM were both primarily innervated by the pudendal nerve branches in 13 cadavers (76.5%) each. The ICM was primarily innervated by the direct sacral nerves S3 and/or S4 in 11 cadavers (64.7%).
authors.affiliation: Division of Female Pelvic Medicine and Reconstructive Surgery, Department of Obstetrics and Gynecology, Albert Einstein College of Medicine, 3332 Rochambeau Ave., Bronx, NY 10467, USA. grigorba@yahoo.com
authors.forename: Bogdan A
authors.initials: BA
authors.lastname: Grigorescu
authors.forename: George
authors.initials: G
authors.lastname: Lazarou
authors.forename: Todd R
authors.initials: TR
authors.lastname: Olson
authors.forename: Sherry A
authors.initials: SA
authors.lastname: Downie
authors.forename: Kenneth
authors.initials: K
authors.lastname: Powers
authors.forename: Wilma Markus
authors.initials: WM
authors.lastname: Greston
authors.forename: Magdy S
authors.initials: MS
authors.lastname: Mikhail
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D006801:Humans; D007001:Hypogastric Plexus / Q000033:anatomy & histology; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000294:innervation*; D017773:Pelvic Floor / Q000033:anatomy & histology / Q000294:innervation*; D010502:Perineum / Q000294:innervation*; D012445:Sacrococcygeal Region / Q000294:innervation*