Origin and distribution of femoral nerve of the rocky cavy, Kerodon rupestris (Cavidae)

Rock cavy (Kerodon rupestris Wied, 1820), a rodent mammal from the Cavidae family is highly adapted to conditions of heat and shortage of water and food, mainly in the periods of great drought that periodically devastate the semi-arid of Northeast Brazil. In the literature, few data are found regarding the functional anatomy of the rock cavy, especially involving the anatomy of the nervous system. We aimed to investigate the origin of the femoral nerve close to the intervertebral foramina, its location and distribution for the musculature of the legs, to verify its importance to support further studies for wild animal clinics, and to contribute for the comparative neuro-anatomy. Ten adult rock cavies of different ages were used (4 males and 6 females), that had died in the Wild Animal Multiplication Center (Cemas) of the Rural Federal University of the Semi-Arid, Mossoro. After the fixation in aqueous solution of 10% formalin, the dissection of the abdominal cavity of the animals was accomplished for complete visualization of the femoral nerve. Variations were verified in the number of lumbar vertebrae, as seven animals (70%) had seven lumbar vertebrae, and three (30%) only six, altering the origin of the nerve. On the right side, in four animals (40%) the femoral nerve originated from ventral branches of L5 to L6, four (40%) from L5 to L7, and in two (20%) from L4 to L6. On the left side, in five animals (50%) the femoral nerve originated from the ventral branches of L5 to L6, in three (30%) from L5 to L7, and two (20%) also from L4 to L6.