Estudo anatômico do plexo lombossacral de Tamandua tetradactyla

Abstract

 RESUMOO tamanduá-mirim (Tamandua tetradactyla) é um xenartro da família Myrmecophagidae, encontrado da Venezuela ao sul do Brasil. Estudos apontam que essa é uma das espécies de animais selvagens mais vitimadas em número de atropelamentos, e, muitas vezes, o atendimento clínico adequado aos indivíduos feridos é dificultado pela carência de informações acerca dos mesmos. Visando contribuir com o conhecimento dessa espécie, este estudo teve como objetivo descrever seu plexo lombossacral. Para tanto, foram utilizados quatro cadáveres de Tamandua tetradactyla adultos e de ambos os sexos. O plexo lombossacral dessa espécie é formado pelos ramos ventrais dos nervos espinhais T18, L1, L2, L3, S1, S2, S3, S4, S5. Os nervos integrantes do plexo lombossacral do T. tetradactyla com suas formações mais frequentes foram os seguintes: genitofemoral (T18), cutâneo femoral lateral (T18-L1), femoral (T18, L1-L3), obturador (T18, L1-L3), glúteo cranial (L3-S1), isquiático (L3-S3), pudendo (S3-S4 ou S4-S5), retal caudal (S4 ou S5) e cutâneo femoral caudal (S4-S5). O plexo lombar e sacral dessa espécie é unido, sendo L3 o ponto de união entre eles. Devido ao pequeno número de vértebras lombares, a composição dos nervos do plexo lombossacral do T. tetradactyla apresenta características peculiares que se diferem das características das demais espécies já estudadas, quais sejam, a ausência dos nervos ílio-hipogástrico e ilioinguinal e participação de nervos torácicos na composição dos nervos do plexo lombar, presença de contribuição sacral na composição do nervo obturador e ausência de contribuição lombar na composição do nervo isquiático e um limite mais caudal na extensão do plexo sacral.Palavras-chave: tamanduá-mirim; sistema nervoso; inervação do membro pélvico, Xenarthra ABSTRACT The lesser anteater (Tamandua tetradactyla) is a xenarthra of the Myrmecophagidae family found from Venezuela to southern Brazil. Studies have shown that this is one of the most numerous wildlife species victims of car collisions on roads, and often the appropriate clinical care to injured animals is hindered by the lack of information about them. In order to contribute to the knowledge of this species, this study aimed to describe its lumbosacral plexus. For this purpose, four cadavers of adult specimens of both sexes of T. tetradactyla were used. The lumbosacral plexus of the T. tetradactyla is formed by the ventral rami of spinal nerves T18, L1, L2, L3, S1, S2, S3, S4, S5. The lumbosacral plexus nerves with their most common formations in this species were as follows: genitofemoral (T18), lateral femoral cutaneous (T18-L1), femoral (T18, L1-L3), obturator (T18, L1-L3), cranial gluteal (L3-S1), ischiatic (L3-S3), pudendus (S3-S4 or S4-S5), caudal retal (S4 or S5), and caudal femoral cutaneous (S4-S5

The lumbosacral plexus of the red-rumped agouti (Dasyprocta leporina Linnaeus, 1758) (Rodentia: Caviidae)

“…Likewise, considering that the origin of the pudendal nerve in Spix's yellow-toothed cavy (OLIVEIRA et al, 2014) and in rock cavies (LACERDA et al, 2006) has been attributed to the ventral branches of S 2 and S 3 , we found three specimens of the red-rumped agouti where the origin of this nerve was only from S 3 and two where this nerve originated from S 3 and S 4 . This latter finding is consistent with what has been reported for the collared anteater (CARDOSO et al, 2013).…”

“…The origin of this plexus has also been reported in other mammals. For example, the plexus originates from L 4 L 5 −S 1 S 2 in the ocelot (LOPES et al, 2012), T 18 −L 3 and S 1 −S 5 in the collared anteater (CARDOSO et al, 2013), L 1 to S 3 in the fur seal (CASTRO et al, 2009), L 3 − L 7 and S 1 −S 3 in the dog (GETTY, 1981), L 4 −L 7 and S 1 −S 3 in the cat (GETTY, 1981), and L 4 −L 7 and S 1 −S 3 in the rabbit (MCLAUGHLIN; CHIASSON, 1987); the latter two results are similar to what we observed in the red-rumped agouti.…”

“…Several papers have described the nerves that make up the lumbosacral plexus in the chinchilla (PEREIRA; RICKES, 2011;RONDINI et al, 2005), rock cavy (LACERDA et al, 2006;OLIVEIRA et al, 2011;SANTOS et al, 2006), porcupine (AYDIN et al, 2009), red squirrel (AYDIN, 2010), Spix's yellow-toothed cavy (OLIVEIRA et al, 2010(OLIVEIRA et al, , 2014, lowland paca (TONINI et al, 2014), ocelot (LOPES et al, 2012), and anteater (CARDOSO et al, 2013;CRUZ et al, 2014); however, to date, there is no description of the union of nerves that make up the lumbosacral plexus of the red-rumped agouti.…”

Origin and Antimeric Distribution of the Femoral Nerves in New Zealand Rabbits

“…Aydin (2009) observed that in the porcupine (Hystrix cristata), the femoral nerve originated mainly from the ventral branches L2 and L3, with contributions from T15 and L1, different from that observed in the present investigation. Cardoso et al (2013) studied the composition of the lumbosacral plexus of the collared anteater (Tamandua tetradactyla) and observed the contribution of lumbar branches (L1-L3) in all studied specimens, and also the participation of T18 in 75% of them in the formation of the femoral nerve. This formation resembles that of the porcupine (T15, L1-L3) (Aydin), and differs from that observed in rabbits of this study.…”

“…Souza et al (2013) studied the branches of the femoral nerves in the giant anteater (Myrmecophaga tridactyla) and found that the origins in the right and left antimeres occurred from ventral branches of the first, second and third lumbar spinal nerves. However, Cruz et al (2014), also analyzing the giant anteater (Myrmecophaga tridactyla), observed participation of thoracic segments (T15, T16) in the formation of the femoral nerve.…”