Point 7






Vent Horn

Lat Horn





Letís go through this by making a lesion of each of the pathways or cell groups discussed so far. We will make these lesions at spinal level T1. You will soon discover how much you know!!

Dorsal Root Entry ZoneThe lesion in this area interrupts the lateral and medial divisions of the dorsal root and the ZL. The interruption of the dorsal root means that NO sensory information gets into the brain from the area of the ipsilateral body innervated by T1 dorsal root. This includes 2 pt. discrimination, vibration and conscious proprioception (alpha-betas), unconscious proprioception (1a, 1b and II) and pain and temperature and crude touch (Cs and deltas). In addition, remember that pain and temperature fibers ASCEND IPSILATERALLY for two segments before they enter the dorsal horn at T1. The lesion interrupts these fibers too. The ascending delta and C fibers from T3 are headed for the dorsal horn at T1--they are dead. The ascending fibers from T2 are headed for the dorsal horn at C8--they are dead!! And of course, the delta and C fibers coming in at T1 via the dorsal root are dead!!! Thus, on the IPSI. side the pain and temp. loss is from T1-T3. The loss of all sensory information from T1 means that no reflexes (stretch, painful) can occur via this dorsal root.