Lack of somatotopy among corticospinal tract fibers passing through the primate craniovertebral junction and cervical spinal cord: pathoanatomical substrate of central cord syndrome and cruciate paralysis

In Brief The authors made a systematic and quantitative investigation of macaque corticospinal tract (CST) organization in the craniovertebral junction (CVJ) and cervical spinal cord. They found no evidence for somatotopic organization of CST fibers at these levels, and therefore reject the concept that somatotopy explains the greater impairment of upper-limb movement, compared with lower-limb movement, following CVJ/cervical spinal cord injury. Other explanations must be considered, including the greater CST contribution to upper- versus lower-limb movement.