Características anatômicas do plexo braquial de bicho-preguiça-de-coleira (Bradypus torquatus Illiger, 1811)

Abstract

Oito cadáveres machos e fêmeas previamente formolizados de bicho-preguiça-de-coleira (Bradypus torquatus) foram utilizados para a identificação da origem, nervos e território de inervação do plexo braquial, visando o estabelecimento de um padrão anatômico para a espécie. O plexo braquial de bicho-preguiça-de-coleira derivou-se dos nervos espinhais C7 a C10 e T1 a T2, sendo a participação de T2 variável. Os nervos espinhais originaram os troncos cranial e caudal que se uniram e formaram um tronco comum que emitiu dois fascículos, a partir dos quais se originaram todos os nervos do plexo braquial, com exceção dos nervos peitorais, torácico longo e supraescapular, que surgiram antes da formação do tronco comum. A organização do plexo braquial em troncos e fascículos, com posterior origem dos nervos periféricos, indica a contribuição da maioria dos nervos espinhais relacionados na composição dos nervos periféricos e a possibilidade de comprometimento de grande parte do membro torácico em situações de traumas ou lesões.

BRACHIAL PLEXUS IN THE Leopardus geoffroyi

“…Often these movements are made naturally by L. geoffroyi in its habitat. Mammals of other orders which have a brachial plexuses formed by at least five ventral branches include the monotremes (16) , Myocastor coypus (17) , Bradypus variegatus (18) , Bradypus torquatus (19) , Hydrochaeris hydrochaeris (20) , Agouti paca (21) , Tamandua tetradactyla (22) , Myrmecophaga tridactyla (23) , Sus scrofa (24) and human (25) and non-human primates (26,27,28,29) . According to the study by Allam et al (30) , a plexus formed by four ventral branches is characteristic of those species whose thoracic limbs are limited to supporting body weight and to specialised cursorial locomotion, and which are constitutively deprived of an ossified clavicle, such as, for example, canids and ungulates.…”

“…Parada et al (12) proposed that the origin of this plexus migrated cranially during evolution, reaching C4 for some monkeys and even C3 for some humans individuals. Nevertheless, the presence of C4 forming the brachial plexus of Ornithorhynchus anatinus and Tachyglossus aculeatus (16) , B. variegatus (18) , B. torquatus (19) and H. hydrochaeris (20) , among others, shows origin of brachial plexus in cranial branches is not a feature of recent species. These results give coherence to the hypothesis by Carpenter (11) , which suggests that variations in the most cranial origin of the plexuses result from the position of the insertion of limb buds compared to the neuro-axis of each species.…”

“…For human and non-human primates (10,41 ), monotremes (16) , Hippopotamus amphibius (5) and B. torquatus (19) , for example, the trunk arrangement occurs as follows: superior or cranial; medial and inferior or caudal, with each trunk being a connection between nerves C5 and C6, C7, C8 and T1, respectively. For L. geoffroyi, there was no formation of such trunks, occurring very distinct branches origin, similar to domestic mammals (7) .…”

Brachial plexus formation in Jaguarundi (Puma yagouaroundi)

“…Species with skilled thoracic limbs usually have the brachial plexus formed by five or more ventral spinal branches. It is the case of humans (Guday et al, 2017) and non‐humans primates (Cruz & Adami, 2010; Kikuchi et al, 2011; Santos‐Sousa et al, 2016; Souza‐Junior, Carvalho, et al, 2018), xenarthrans (Adami et al, 2013; Cruz et al, 2012; Medeiros‐Do‐nascimento et al, 2019; Souza et al, 2014) and the carnivores L. geoffroyi (Souza‐Junior, Wronski, et al, 2018), Nasua (Felipe, 2014) and Herpestes javanicus (Yoshitomi et al, 2004). According to Allam et al (1952), ungulates, which use the thoracic limbs in a restricted way, have a plexus restricted to four spinal branches, that is the case with some domestic and wild ungulates (Atoji et al, 1987; Magilton, 1966; Vieira et al, 2013).…”

Morphological variation of the brachial plexus in four phyllostomid bat species (Chiroptera, Phyllostomidae)

“…Due to its importance for locomotion, the brachial plexus morphology has been studied in several mammal orders, such as Monotremata (Koizumi & Sakai, 1997; Miller, 1934), Diprotodontia (Miller, 1934), Didelphimorphia (Alves et al, 2016; Chitolina et al, 2017), Pilosa (Cruz et al, 2012, 2013), Cingulata (Fernandes et al, 2015), Perissodactyla (Backus et al, 2016; Ghoshal, 1982b), Artiodactyla (Endo et al, 2009; Ghoshal, 1982c, 1982d; Moura et al, 2007; Schulte & Smith, 1918; Sekiya et al, 2011; Solounias, 1999; Strickler, 1978; Yoshitomi et al, 2012), Carnivora (Chagas et al, 2014; Demiraslan et al, 2015; Ghoshal, 1982a; Pinheiro et al, 2013; Souza‐junior et al, 2014; Yoshitomi et al, 2004), Pholidota (Kawashima et al, 2015), Rodentia (Angélica‐Almeida et al, 2013; Araujo‐Junior et al, 2016; Barton et al, 2016; Cevik‐Demirkan et al, 2007; Fioretto et al, 2003; Gamba et al, 2007; Scavone et al, 2008), Lagomorpha (Mohiuddin et al, 2011), Dermoptera (Kawashima et al, 2012; Leche, 1886), and Primates (Araújo et al, 2012; Cruz & Adami, 2010; Kerr, 1918; Miller, 1934; Santos‐Sousa, 2016).…”