Background:The common marmoset (Callithrix jacchus) belongs to the family Cebidae and Subfamily Callitrichinae, a group formed by the smallest anthropoid primates. It is a very common species and adapts easily to captivity, an aspect that encourages the clandestine capture of these animals and makes them susceptible to wounds resulting from clandestine rearing and inadequate management, so that studies to understand the species are extremely important. With the objective of supplying anatomic bases for the practice of epidural anesthetic, data were studied regarding the topography of the common marmoset (Callithrix jacchus). Materials, Methods & Results:The study was carried out at the Laboratory of Veterinary Anatomy at the Federal University of Campina Grande (UFCG), PA, Brazil. Ten adult common marmosets (Callithrix jacchus) were used, 5 males and 5 females, with different causes of death. A round workbench magnifying lamp was used to better visualize the dissecation field. Number 15 scalpel blades, surgical pincers and scissors were used to dissect. After fixing in 10% formaldehyde aqueous solution, dissecation was made along the mid dorsal line, from the cranial thoracic region to the tail base to expose the vertebral arches and measure the intervertebral spaces. The vertebral arches were removed, and consequently the spinal dura mater was exposed, that was sectioned longitudinally to expose the spinal chord and identify the lumbar intumescence, the conus medullaris and the cauda equina. The length of the conus medullaris was measured and its skeletopy was established. The body and tail length data were submitted to analysis of variance and the means were compared by the Tukey test at 5% probability. The mean value of the conus medullaris length was 1.4 cm, while the anatomic location of the conus medullaris varied slightly among the animals, but did not pass the limit between L3 for the base and L6 for the apex. On average, the lumbosacral space measured 3.03 mm, that is sufficient to introduce a needle similar to that used in syringes for insulin injection. The results of this study suggest the lumbarsacral space as location for epidural anesthetic application in Callithrix jacchus, at a safe point situated in the center of an isosceles triangle, the base of which is found when a line is drawn from one side of the pelvis to the other, and the apex corresponds the spinal process of the first sacral vertebra. Discussion: The anatomic location of the conus medullaris is different compared to two other primate species, the red handed tamarin (Saguinus midas), in which the cone base was registered at L4 and the apex at S2, and the common squirrel monkey (Saimiri sciureus) where the conus medullaris base occurs at L7-8 and the apex at S3 or Cc1. However, some similarities with other mammal groups were observed in the conus medullaris topography, such as the black-striped capuchin (Sapajus libidinosus). The mean conus medullaris length of the species Callithrix jacchus of 1.4 cm was close to that observ...

Background: In captivity, capuchin monkeys compete for space and rank. Fights can result in traumas, especially to the limbs, requiring interventions that are often outpatient. Local anesthesia as a tool in these procedures, as an aid to chemical restraint, is very relevant for small outpatient surgeries, or even for pain relief. Knowledge of peripheral nerve anatomy is essential to perform local anesthesia. Thus the objective of the present study was to determine, by anatomical studies of the brachial plexus region, the best access pathways for anesthetic blocking of the nerve.Materials, Methods & Results: Seven adult capuchin monkeys (Sapajus libidinosus) were used, weighing 2-3 kg, fixed and preserved in formaldehyde aqueous solution at 10%. In five of these animals the supraclavicular, infraclavicular and axillar regions were dissected to visualize the muscles, clavicle and bracchial plexus nerves. An analogical pachymeter was used to measure the depth of the plexus in relation to the cranial and caudal clavicle face and axillary fossa, comparing the length of two hypodermic needles (13x4.5 mm and 15x5 mm). Simulation of the anesthetic block was tested in two animals: before dissecting an acrylic varnish solution was injected using a syringe and 13x4.5 mm needle in the supraclavicular, infraclavicular regions and axillary fossa. To assess the positioning points of the syringe, dissection was performed and the varnish perfusion in the plexus was observed. For the anesthetic block in the supraclavicular region the dorsal median of the clavicle with a 95º deltoclavicular angle with the needle perpendicular to the skin was taken as point of reference. In the infraclavicular the reference point was the caudal face of the median clavicle with an 80º deltoclavicular angle. In the axillar region, with the limb at 90º, the syringe was positioned perpendicular to the axillar at the height of the mid portion of the thorax. The mean and standard deviation of the skin-brachial plexus distance for the supraclavicular, infraclavicular and axillar techniques were, respectively, 1.76 ± 0.1387 cm, 1.12 ± 0.239 cm and 1.59 ± 0.365 cm. These data showed the viability of executing the anesthesia technique by three access pathways. However, in the supraclavicular access pathway in the anesthetic simulation with the 13x4.5 mm hypodermic needle, the stain diffused to the plexus, showing, when compared with the 1.76 cm mean skin- plexus distance a safe distance to prevent the needle from perforating the nerve.Discussion: The techniques reported in the human literature for brachial plexus block presented a series of complications, with incomplete blocks and hemorrhages when the axillar access pathway was used and presented risk of pneumothorax in the supraclavicular. In the capuchin monkey the supraclavicular access pathway in anesthetic simulation with 13x4.5mm hypodermic needle showed a safe distance for the needle not to perforate the nerve, so that the use of this needle could be indicated in 2-3 kg animals. However, hypodermic needles are not recommended for use in this area because of the risk of perforating the subclavicular artery close to the plexus. As an alternative some anesthesiologists use the infraclavicular access pathway with atraumatic needles recommended for brachial plexus block, with relative success and fewer complications. Although the supraclavicular region showed the best depth in relation to the technique used here, anesthetic tests should be made to confirm the efficaciousness of executing the brachial plexus anesthetic technique in capuchin monkeys using atraumatic needles for nerve block.