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Comparative analysis of the origin of the brachial plexus of the collared peccary (Tayassu tajacu)

Collared peccary (Tayassu tajacu) belongs to the Tayassuidae family, characterized by a "collar" of white hairs that cross behind the neck and extend bilaterally in front of the shoulders. It can be found from south-western United States to Argentina. In the literature a shortage of data is verified regarding the functional anatomy of the collared peccaries, especially of studies that involve the anatomy of the brachial plexus. To elucidate the behavior of this plexus of collared peccaries and with the purpose to contribute for the development of compared anatomy, this study was accomplished. Thirty animals of different ages were used (17 males and 13 females) coming from the Wild Animal Multiplication Center of the "Universidade Federal Rural do Semiárido" Mossoró, Rio Grande do Norte, Brazil. After slaughter bilateral dissection of the brachial plexuses took place, and the results were registered in schematic drawings and the dispositions grouped in tables for subsequent statistical analysis based on the percentile frequency. It was found that the Plexus brachialis of collared peccaries is the result of established communications, mainly among the Rami ventrales of the last three cervical nerves and of the first two thoracic nerves, having a contribution of the fourth and fifth cervical nerves in 16.67% and 50.00% of the cases, respectively. In 40.00% of the dissections the most frequent plexus was of the type C6, C7, C8, T1 and T2. The main nerves derived from brachial plexus of the collared peccaries and its respective origins had been: Nervus suprascapularis (C6, C7), Nn. subscapulares (C5, C6 e C7 or C6 e C7), N. axillaris (C6, C7), N. musculocutaneus (C7, C8), N. medianus (C7, C8, T1, T2), N. radialis (C8, T1, T2), N. ulnaris (C8, T1, T2), cranialis (C7), and caudalis (C7, C8) Nn. pectorales , N. thoracodorsalis (C6, C7, C8), N. thoracicus longus (C7, C8), and N. thoracicus lateralis (C8, T1, T2).

Brachial plexus; neuroanatomy; wild animals


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