Lab 6 (ƒ9) Descending Pathways to the Spinal Cord
Clinical Correlate-Brown-Sequard Syndrome
When the spinal cord is hemisected, the Brown-Sequard syndrome results. Following recovery from a high cervical lesion (e.g., C4), this syndrome is characterized by a spastic hemiplegia of the ipsilateral arm, forearm and leg, with a Babinski sign (extensor response to plantar stimulus) and abolished abdominal reflexes, exaggerated patellar and Achilles reflexes (lateral corticospinal and non-corticospinal descending pathways), loss of discriminative touch and proprioception on the ipsilateral side (posterior funiculus), and loss of pain and temperature sensibility on approximately the same region of the contralateral side of the body (spinothalamic tract). The ipsilateral pupil is constricted and there is a bilateral diminution of sweating (descending reticulospinal tract to preganglionic sympathetic). The functions of the bladder, rectum, and genital organs are usually not interfered with because they are bilaterally innervated.