SPINAL CORD INJURY
Traditional neuroanatomy has described the effects of partial spinal cord section. Sensory changes are said to be dissociative. In the Brown-Séquard syndrome of partial cord section, selective modalities are lost because the spinothalamic pathway (temperature and pain) crosses the midline near the level of the spinal root and the dorsal column (proprioception and mechanoreceptor) does not. Similarly, the development of a syrinx, a cystic lesion within the spinal cord, is associated with characteristic sensory and motor changes. There is a loss of pain sensation due to destruction of fibres crossing over in the spinal cord, but light touch and positional sense is preserved.