Lumbosacral plexus in Brazilian Common Opossum.

The opossum has been suggested as an animal model for biomedical studies due to its adaptability to captivity and number of births per year. Despite many studies on morphology and experimental neurology using this opossum model, the literature does not offer details of the nerves of the lumbosacral plexus in this species. Ten lumbosacral plexus were dissected to describe the peripheral innervations of the Brazilian Common Opossum (Didelphis aurita) and compare the results with Eutheria clade species. The tensor fasciae latae muscle was absent and there was only one sartorius muscle for each limb. The distribution of the nerves were similar to other mammals, except for the caudal gluteal nerve, sartorius muscle innervations and the position of the pudendal nerve which arose from the major ischiatic foramen together with the ischiatic nerve, the cranial gluteal nerve and the caudal gluteal nerve. No anatomical variation was found. The special position of the pudendal nerve suggested that the Brazilian Common Opossum is a better model than rats or rabbits in surgical procedures with that specific nerve. In addition, the study revealed that the pelvic limb nerves are not an invariable structure of reference for muscle homology and homonym as reported previously. New investigation using other species of opossums are necessary to best comprehend the lumbosacral plexus distribution in the Methatheria clade and to confirm that other opossum species is eligible as a good model for pudendal nerve studies.

Gross morphometry of the heart of the Common marmoset.

The Callithrix jacchus is a Brazilian endemic species that has been widely used as an experimental model in biomedical research. Anatomical data are necessary to support experimental studies with this species. Eleven hearts of C. jacchus from the German Primate Centre (DPZ) have been studied in order to characterize their gross morphometry and compare them with other animal models and human. Biometric data were also obtained. The mean values for morphometry of the hearts did not show any significant difference between male and female. The relative heart weight was similar to human, bovine and equine species. Considering those aspects, the C. jacchus could be used as non-human primate experimental model for biomedical studies on heart.