what happens when the dorsal root of a spinal nerve is cut
Dorsal root of spinal nerve The medial division of the dorsal root contains myelinated fibres of larger diameter. These transmit information of discriminative touch, pressure, vibration, and conscious proprioception originating from spinal levels C2 through S5. These fibers are pushed in towards the posterior median sulcus to form the gracile fasciculus and the cuneate fasciculus of the posterior column–medial lemniscus pathway. If the dorsal root of a spinal nerve were severed it would lead to numbness in certain areas of the body.
Cauda equina In humans, the spinal cord stops growing in infancy and the end of the spinal cord is about the level of the third lumbar vertebra, or L3, at birth. Because the bones of the vertebral column continue to grow, by about 12 months of age, the end of the cord reaches its permanent position at the level of L1 or L2 (closer to the head). However, due to normal anatomical variations, the final cord end position may occur anywhere from T12 twelfth thoracic vertebra (T12) to L3. Individual spinal nerve roots arise from the cord as they get closer to the head, but as the differential growth occurs, the top end of the nerve stays attached to the spinal cord while the lower end of the nerve exits the spinal column at its proper level. This results in a "bundle"-like structure of nerve fibers that extends caudally from the end of the spinal cord, gradually declining in number further down as individual pairs leave the spinal column.