The conus medullaris (Latin for medullary cone) is the tapered, lower end of the spinal cord.It occurs near lumbar vertebral levels 1 (L1) and 2 (L2), occasionally lower. The upper end of the conus medullaris is usually not well defined.After the spinal cord tapers out, the spinal nerves continue to branch out diagonally, forming the cauda equina.onus medullaris syndrome is a collection of signs and symptoms associated with injury to the conus medullaris. It typically causes back pain and bowel and bladder dysfunction but weakness and sensory loss is uncommon.