Estudo anatômico do plexo lombossacral de Tamandua tetradactyla

The lumbosacral plexus in two Didelphis species (Didelphidae, Didelphimorphia): origin and nerve distribution

Morphological studies provide knowledge that allow us to understand how animals interact with the natural environment or the captivity. The goal of this study was to describe the origin and antimeric distribution of lumbosacral plexus nerves in Didelphis aurita and D. albiventris. Fourteen adult cadavers of D. aurita, seven males and seven females, and 13 adult cadavers of D. albiventris, nine males and four females were used. The specimens were sexed, identified, fixed and dissected until the origins of the lumbosacral plexus nerves were exposed. Data were represented as absolute frequency and simple percentage. The lumbosacral plexuses derived a trunk for the femoral and obturator nerves from the ventral branches of L3-L4 (75%) in D. aurita, and in D. albiventris the femoral nerve of L3-L4 (73.1%) and the obturator nerve of L3-L4 (61.5%). In both species, formation of a lumbosacral trunk derived from L5-L6-S1 occurred in 78.6% of D. aurita and 61.5% of D. albiventris. The origin and distribution of lumbosacral plexus nerves of the studied species present similarities with domestic and wild eutherian mammals.

Evolutionary aspects on the origin, distribution and ramifications of the ischiadicus nerve in the giant anteater (Myrmecophaga tridactyla)

ABSTRACT This work aimed to describe the origin, distribution, and ramifications of the ischiadicus nerve in the giant anteater and to provide anatomical data which could explain not only the evolutionary aspects but also provide important information for other related works. For the present study, four specimens were used, prepared by perfusion of 10% formaldehyde solution via the femoral artery, for conservation and dissection. The origin of the right and left ischiadicus nerves in the giant anteater from the ventral ramification of the third lumbar (L3) and the first (S1), second (S2), and third (S3) sacral spinal nerves. These nerves were symmetrical in all animals studied. The distribution and ramification occurred to the superficial, middle, and deep gluteal, gemelli, piriform, quadratus femoris, tensor fasciae latae, caudal crural abductor, cranial and caudal parts of the biceps femoris, adductor, semitendinous, and cranial and caudal parts of the semimembranous muscles. Based on the origins of the ischiadicus nerves, there is a caudal migration in the nerve location in animals in a more recent position on the evolutionary scale due to reconfiguration of the lumbosacral plexus, resulting from the increase in a number of lumbar vertebrae. There is no complete homology of the muscle innervation.

ORIGEM E DISTRIBUIÇÃO ANTIMÉRICA DOS NERVOS FEMORAIS EM CAPRINOS RECÉM-NATOS DA RAÇA SAANEN

O nervo femoral foi estudado em 33 caprinos recém-natos da raça Saanen (22 machos e 11 fêmeas), que, após morte natural, foram fixados com solução de formaldeído a 10%. Nos machos, o nervo femoral teve sua origem nos ramos espinhais ventrais de L4 e L5 em oito animais (36%); em seis animais (27%) teve sua origem nos ramos espinhais ventrais de L5 e L6; em cinco animais (23%) teve sua origem no ramo espinhal ventral de L5; em dois animais (9%) teve sua origem nos ramos espinhais ventrais de L4, L5 e L6; em um animal (5%) teve sua origem dos ramos espinhais ventrais de L5 e L6 e no ramo espinhal ventral de S1. Nas fêmeas, teve sua origem nos ramos espinhais ventrais de L4 e L5 em sete animais (64%); em três animais (27%) teve sua origem nos ramos espinhais ventrais de L5 e L6 e em um animal (9%) teve sua origem nos ramos espinhais ventrais de L4, L5 e L6. Os nervos femorais emitiram, em todos os animais, número variável de ramos para os músculos psoas maior, psoas menor, quadríceps femoral, sartório e pectíneo.