Acta Veterinaria Brasilica June 12 (2018) 55-61 ____________________________ * Corresponding author: daianersterra@gmail.com http://dx.doi.org/10.21708/avb.2018.12.2.7349 Acta Veterinaria Brasilica Journal homepage: https://periodicos.ufersa.edu.br/index.php/acta/index Original Article Anatomy of the spinal cord of Alouatta belzebul Daiane Rodrigues de Souza Terra 1 *, Dayane Kelly Sabec-Pereira 3 , Fabiano Campos Lima 2 , Fabiana Cristina Silveira Alves Melo 4 , Fabiano Rodrigues Melo 2 , Kleber Fernando Pereira 5 1 Programa de pós-graduação em Biociência Animal, Universidade Federal de Goiás, Regional Jataí, Jataí, Goiás, Brasil. 2 Curso de Ciências Biológicas, Universidade Federal de Goiás, Regional Jataí, Goiás, Brasil. 3 Curso de Medicina, Faculdade Assis Gurgacz, Cascavel, Paraná, Brasil. 4 Departamento de Biologia Animal, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil. 5 Curso de Medicina, Universidade Federal do Paraná – Campus Toledo, Toledo, Paraná, Brasil. ARTICLE INFO ABSTRACT Article history The genus Alouatta hosts species popularly known as red-handed howler, presenting wide geographic distribution and being found in several biomes. The objective is to describe the anatomy of the spinal cord of Alouatta belzebul specimens, focusing on the topography of the medullary cone, stressing the cervical and lumbar intumescences and cauda equina, to provide anatomical data and compare it with other species to assist in anesthetic and surgical procedures. Four animals were received for scientific research, post mortem, from the fauna rescue program of the Hydroelectric Plant of Belo Monte - Pará, and they were fixed in 10% formaldehyde solution. Structures such as the medullary cone, cervical and lumbar intumescence, and cauda equina were photographed (Sony α200-10.2 mpx). After thawing, we measured the specimens and observed a size of 80 to 82 cm from head to toe. After the skin and musculature were removed, it was observed that the spine of all specimens presented 7 cervical, 13 thoracic, 5 lumbar and 3 fused sacral vertebrae. The spinal cord was exposed after the removal of vertebral arches, it has 22 cm length in all animals, presenting the cervical intumescence between C3 and C6 vertebrae, with average of 2.2 cm and lumbar intumescence between T11 and T12 vertebrae, with average of 1.65 cm. The medullary cone is located between T12 and L1 vertebrae, with average of 1.5 cm, and the cauda equina between L1 and S3, with an average of 15 cm. This study has an important role as the basis for epidural anesthesia in the species. Received 03 October 2017 Received in revised form 23 March 2018 Accepted 28 March 2018 Keywords: Comparative anatomy Anesthesia Medullary Cone Intumescence INTRODUCTION Advances in comparative animal anatomy possess fundamental importance due to the scarcity of information available in the literature. The anatomical descriptions subsidize comparative and evolutionary studies, since through these descriptions one can succeed in anesthetic procedures essential to diagnostic and surgical processes (SLULLITELL, 2008). Regional anesthetic techniques are used with a suitable safety margin, aiming to anesthetize spinal nerves of the lumbar and sacral regions, thus the location of anesthetic application in the epidural space varies according to the species and the ending site of the spinal cord. The use of sites caudal to the medullary cone makes the application technique safer, consequently avoiding spinal cord injuries and helping professionals who need to perform surgical procedures (GREGORES et al., 2010; SOUZA et al., 2014). Primates of the genus Alouatta are medium-sized mammals, yet they are considered robust animals and well-known for long-range vocalization. Their jaw accommodates a rather large hyoid bone, mainly in males, which forms an oval resonance chamber, responsible for the characteristic vocalizations related to group location and territory defense (HIRSCH et al., 1991). Research about these primates involves diet, vocalization, life style and ecology of the species (AGUIAR et al., 2003; BICCA-MARQUES et al., 2009; BICCA-MARQUES, 2003; CAMARGO, 2005; GRECORIN,