TOPOGRAFIA DO CONE MEDULAR NA ARIRANHA (Pteronura brasiliensis Zimmermann, 1780)

Aiming to offer the anatomical bases for epidural anesthesia, particularly relative to the topographical anatomy of the medullar cone, three specimens of adult giant otter (Pteronura brasiliensis), two male and one female, after natural death, were dissected. Those animals were donated from Laboratory of aquatic mammals (INPA – National Institute for Amazonia Research).  After the dissection were observed: a) in two animals (66.6%), one male and one female, the medullar cone apex is close to fourth lumbar vertebra (L4) and, in other one animal (33.3%), male, between the L3 and L4 vertebrae; b) the medullar cone length is 5.50cm in alls animals to this study, and your base is close to L3 (66.6%) or between the L2 and L3 vertebrae (33.3%); c) the lumbar enlargement (Intumescentia lumbalis), that continuous to the base of the medullar cone, were noted between the T12 and L2 vertebrae. KEY WORDS: Anatomy, medullar cone, Pteronura brasiliensis.