Origem e distribuição dos nervos do plexo lombossacral de duas espécies de Didelphis (Didelphidae, Didelphimorphia).

Abstract

Morphological studies provide knowledge that allows understanding how animals interact with the natural environment or captivity. The aim of this study was to describe the origin and antimeric distribution of the lumbosacral plexus nerves of Didelphis aurita and D. albiventris, as well as to describe the skeleton and dimensions of the lumbar intumescence of the species in this study. Fourteen adult cadavers of D. aurita were used, seven males and seven females, from the Serra dos Órgãos National Park (PARNASO), 13 adult cadavers of D. albiventris, seven males and two females, from the collection of the Animal Anatomy Laboratory of the Federal University of Pampa (UNIPAMPA), and two males and two females from the Mammal Collection of the National Museum / UFRJ (MNRJ). The specimens were sexed, identified and fixed. Then, they were dissected until exposure of the origins of the lumbosacral plexus nerves. The data were represented in absolute frequency and simple percentage. The right and left lumbosacral plexuses derived a trunk for the femoral and obturator nerves of the ventral branches of L3-L4 (75%) in D. aurita, and in D. albiventris the femoral nerve of L3-L4 (73.1%) and obturator nerve of L3-L4 (61.5%). In the two studied species there was formation of a lumbosacral trunk derived from branches of L5-L6-S1 in 78.6% in D. aurita and in 61.5% in D. albiventris. Lumbar intumescence originated from L2-L5 (46.2%) with an average length of 4.69 ± 0.62 cm in D. aurita and L2-L4 (38.5%) with an average length of 4.38 ± 0,71cm in D. albiventris. There was a positive correlation between lumbar intumescence and rostrosacral length in D. aurita (p = 0.0141 and r = 0.6598) and D. albiventris (p = 0.0323 and r = 0.5941). There was no significant difference in size between the lumbar intumescence of the two species (p = 0.3164). The origin and distribution of the lumbosacral plexus nerves, the skeleton and dimensions of the lumbar intumescence of the studied species show similarities with domestic and wild euterium mammals. The lumbosacral plexuses in D. albiventris and D. aurita were formed by contributions from the last four lumbar ventral branches of the spinal nerves (L3, L4, L5 and L6) and the first sacral (S1)