THE SPINAL CORD 547 



;t is, however, believed by some investigators that those fibers which sub- 

 . erve the sense of touch do not decussate at once, but ascend in the column 

 k >f Goll as far as the medulla oblongata, where they, in common with the 

 ibers coming from the muscles, arborize around the nerve-cells hi the gracile 

 ind cuneate nuclei. 



The pathways for the impulses that give rise to the different sensation 



lave been variously located by different observers, e.g., in the gray matter, 



n the limiting layer, and hi the antero-lateral tract of Gowers; the pathway 



or the impulses that give rise to temperature sensations has been located in 



,he gray matter; the pathway for tactile impressions has been located in the 



posterior columns, though this is not beyond dispute. The pathway for 



)ain sensations has been located in Gowers' tract. 



The results on both sides of the body, which follow a transverse lesion, 

 Experimental or traumatic, of one-half of the spinal cord in the thoracic 

 egion for example, are shown in the subjoined table, a grouping of results 

 vhich is known as the Brown-Se"quard "Symptom Complex." It is under- 

 stood, of course, that these results are observed below the level of the lesion. 



THE BROWN-SEQUARD SYMPTOM COMPLEX 



Side Opposite of Lesion. Side of Lesion, 



c. Temperature sensibilities abolished, i. Temperature sensibilities re- 

 tained. 



2. Painful sensibilities abolished. 2. Painful sensibility retained. 



3. Pressure (painful) sensibilities abol- 3. Pressure (painful) ; sensibilities 

 ished. retained. 



\. Passive position of limb and direc- 4- Passive position of limb and di- 

 tibn of movement, retained. rection of movement, abolished. 



5. Light pressure or light touch, may or 5. Light pressure or light touch, 

 may not be abolished. retained. 



5. Tactile discrimination, retained. 6. Tactile discrimination, abol- 

 ished. 



7. Cutaneous localization, abolished. 7- Cutaneous localization, retained. 



k Voluntary motion, retained. 8. Voluntary motion, abolished. 



From a study of this table it is apparent: (i) that some forms of sensor 

 impulses (those of pain and temperature sensibility) cross soon after their 

 Entrance and pass up the opposite side of the cord; (2) that other forms of 

 sensor impulses (those of the sense of passive position of a limb and 

 direction of movement and tactile discrimination (Head)) do not cross, but 

 pass up on the same side as the entering dorsal nerve roots; (3) hat tacti 

 sensibility may or may not be abolished on the side opposite the lesion; am 

 i,( 4 ) that the sense of cutaneous localization may be dissociated from the sense 

 of passive position, and remain intact when the latter is absent Head) 



P Encephalo-sp nal or Motor Conduction.-The encephalo-spinal or 

 motor pathway extends from the cerebral cortex to ffff*j"^** 



encephalic motor nerves and the ventral spinal nerves all of which ar 

 tributed to skeletal muscles. 



