9 - Anatomical variation in the path of the sciatic nerve and their clinical and surgical implications: case report

Poster Board Number: 9
There are separate poster presentation times for odd and even posters.
Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Helder Pimenta - Universidade do Estado do Amazonas; Camilly Batalha - Universidade do Estado do Amazonas; Ketholyn Bespalhuk - Universidade do Estado do Amazonas; Isabele Bicharra - Universidade do Estado do Amazonas; Daianny Brandão - Universidade do Estado do Amazonas; Carlos Castro - Universidade do Estado do Amazonas; Matheus Clos - Universidade do Estado do Amazonas; Mathews da Costa - Universidade do Estado do Amazonas; Marcela de Azevedo - Universidade do Estado do Amazonas; Rafael de Oliveira - Universidade do Estado do Amazonas; Francisco de Sales Filho - Universidade do Estado do Amazonas; Mariana Ferreira - Universidade do Estado do Amazonas; Hélio Fontinelle Neto - UFAM; Agatha Azedo - Universidade do Estado do Amazonas; Giovane Gama - Universidade do Estado do Amazonas; Mariana Guimarães - Universidade do Estado do Amazonas; Matheus Lopes - Universidade do Estado do Amazonas; Matheus Máximo - Universidade do Estado do Amazonas; Ianê Martins - Universidade do Estado do Amazonas; Thiago Martins - Universidade do Estado do Amazonas; Maria Miranda - FAMETRO; Júlia Moraes - Universidade do Estado do Amazonas; Julia Paoleschi - Universidade do Estado do Amazonas; Karina Pessoa - Universidade do Estado do Amazonas; Danilo Reis - UEA; Eliza Ribeiro - Universidade do Estado do Amazonas; Maria Luiza Schneider - Universidade do Estado do Amazonas; Adam Silva - Universidade do Estado do Amazonas; Samira Silva - Universidade do Estado do Amazonas; jasmine Walker - UFAM

Abstract Body :The innervation of the lower limbs is a relevant topic in clinical anatomy, as through these studies it is possible to understand the different movements. Among the nerve branches that are sent to the lower limbs, there is the sciatic nerve. The sciatic nerve has its primordial origin in the sacral plexus, originating from the anterior and posterior divisions of the nerves of the fourth lumbar vertebra (L4) to the branches of the third sacral vertebra (S3). However, the growth of studies on anatomical variations has allowed us to observe different conformations in the path of the sciatic nerve and its relationship with the piriformis muscle. There are about 6 different classifications for the positioning of the nerve over the muscle in the gluteal region. Within this scope, the intrinsic relevance of the divisions of the sciatic nerve stands out, more precisely those that ascend below and above the piriformis muscle, which are the central focus of this study (SMOLL, 2010).The present study's primary objective is a detailed investigation of the anatomical variations of the sciatic nerve, with special attention to the different conformations of its path in relation to the piriformis muscle in the gluteal region.During the dissection stage of an older male cadaver, from the Human Anatomy laboratory of the School of Health Sciences of the State University of Amazonas - UEA/ESA, a variation of the left sciatic nerve was observed.In this anatomical variation, the nerve has its division in the gluteal region, being classified as a high division described in more recent research. Furthermore, the peroneal branch can be seen emerging above the piriformis muscle, passing along its posterior part and the tibial branch just below and deep to the piriformis muscle.In the present report, the investigated cadaver presented division above and below the piriformis muscle. According to Beaton and Anson et al. (1938), who developed classifications (types: A. B. C and D) involving the sciatic nerve and the piriformis muscle when studying 240 cadaveric pieces from the gluteal region.In the studied cadaver, the type C variation, in the classification of Beaton and Anson et al. (1938), in the sciatic nerve it is considered rare. This fact converges with the meta-analysis carried out by Tomaszewski et al. (2016), in which the type C variation had a prevalence of 1.9%.The course of the terminal divisions of the sciatic nerve, both above and below the piriformis muscle, has the potential to predispose the occurrence of piriformis syndrome, sciatica and coccygodynia (PAIS et. al., 2013 ).Therefore, it is necessary to understand the variations that may be observed in the sciatic nerve, as this knowledge has relevant applications in clinical and surgical areas.