Anatomy of the medullary conus applied to the epidural route of administration of drugs in capuchin monkeys (Sapajus libidinosus)

Jefferson F. Cordeiro José R.S. Santos Sabrina B.A. Dantas Saul S. Fonseca Rômulo F.F. Dias Gildenor X. Medeiros Pedro I. Nobrega Neto Danilo J.A. Menezes About the authors


This study aimed to describe the topography of the conus of capuchin monkey (Sapajus libidinosus) to provide support for anesthetic procedures, as well as examinations of myelography and CSF collection, among other procedures using the epidural route. Eight animals were dissected, six males and two females, of different ages. The skin was countered for removal of the dorsal musculature for exposure of the entire spine and identification of the lumbar and sacral vertebrae. To establish the end of the spinal cord and to measure the length of the conus medullaris, we opened the lumbosacral spinal canal through side section of the vertebral arches. The dura mater was sectioned to visualize the conus and to observe the topographical relation with the vertebrae. All animals showed five lumbar vertebrae and three sacral vertebrae. The vertebrae were in general very closed with the spinous processes well developed and directed cranially. The conus of capuchin monkeys was located between the L2 and L5 vertebrae, with the base mostly in the L3 vertebra, and the peak in L4. The body length (interarcual space occiptoatlântico until sacrocaudal interarcual space) ranged from 22.9 to 31.8cm, with a mean of 27.44±3.1cm while the medullary cone length ranged from 1.70 to 3.51cm, with a mean of 2.47±0.57cm. There was no correlation between body size and length of the medullary cone (r=0.212). It is concluded that despite the variations in length and positioning of the medullary cone, its height does not exceed the lumbosacral joint, making safe access to the epidural space in this way.

Index Terms:
Medullary conus; capuchin monkey; Sapajus libidinosus; esqueletopy; spinal cord; epidural; peridural

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