title: Topography and landmarks for the nerve supply to the levator ani and its relevance to pelvic floor pathologies.
abstract: The aim of this study was to explore the anatomical variations of the nerve to the levator ani (LA) and to relate these findings to LA dysfunction. One hundred fixed human female cadavers were dissected using transabdominal, gluteal, and perineal approaches, resulting in two hundred dissections of the sacral plexus. The pudendal nerve and the sacral nerve roots were traced from their origin at the sacral foramina to their termination. All nerves contributing to the innervation of the LA were considered to be the nerve to the LA. Based on the spinal nerve components, the nerve to the LA was classified into the following categories: 50% (n = 100) originated from S4 and S5 (type I); 19% (n = 38) originated from S5 (type II); 16% (n = 32) originated from S4 (type III); 11% (n = 22) originated from S3 and S4 (type IV); 4% (n = 8) originated from S3, S4, and S5 (type V). Two patterns of nerve termination were observed. In 42% of specimens, the nerve to the LA penetrated the coccygeus muscle and assumed an external position along the inferior surface of the LA muscle. In the remaining 58% of specimens, the nerve crossed the superior surface of the coccygeus muscle and continued along the superior surface of the iliococcygeus muscle. Damage to the nerve to LA has been associated with various pathologies. In order to minimize injuries during surgical procedures, a thorough understanding of the course and variations of the nerve to the LA is extremely important.
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.|Department of Anatomy, Varmia and Mazuria University, Olsztyn, Poland.
authors.forename: Marios
authors.initials: M
authors.lastname: Loukas
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.|Department of Internal Medicine, Lincoln Medical and Mental Health, Bronx, New York.
authors.forename: Shamfa
authors.initials: S
authors.lastname: Joseph
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.|Department of Internal Medicine, SUNY Upstate, Syracuse, New York.
authors.forename: Denzil
authors.initials: D
authors.lastname: Etienne
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Linganna
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.
authors.forename: Barry
authors.initials: B
authors.lastname: Hallner
authors.affiliation: Department of Anatomical Sciences, School of Medicine, St George's University, Grenada, West Indies.|Children Hospital, Pediatric Neurosurgery, Birmingham, Alabama.
authors.forename: R Shane
authors.initials: RS
authors.lastname: Tubbs
mesh_terms: D005260:Female; D006801:Humans; D018482:Muscle, Skeletal / Q000294:innervation*; D017773:Pelvic Floor / Q000294:innervation*; D059952:Pelvic Floor Disorders / Q000473:pathology; D010388:Pelvis; D060525:Pudendal Nerve / Q000033:anatomy & histology*; D012445:Sacrococcygeal Region / Q000294:innervation; D013126:Spinal Nerve Roots / Q000033:anatomy & histology*
keywords: fecal incontinence; levator ani; pelvic floor; pelvic organ prolapse; pudendal nerve; sacral plexus; urinary incontinence