XXXl] SPINAL CORD 237 



(especially in the lower thoracic region) ; in the cervical 

 region it is broader, and is broken up by bundles of 

 transversely cut fibres, and is nearer the surface than 

 in the thoracic region ; in the lumbar region the neck 

 is broad; the apex is near the surface, and the head 

 forms a rather large, roundish mass. 



Nerve-cells of anterior cornu. In the cervical 

 and lumbar regions distinct groups of large nerve-cells 

 are seen; in the thoracic region the nerve-cells are 

 fewer, smaller, and less obviously in groups. 



Clarke's nucleus. This is seen in the thoracic 

 region as an oval area near the neck of the posterior 

 cornu, a little behind the level of the central canal. The 

 cells in it are fairly large, but less obviously multipolar 

 than those of the anterior cornu. Clarke's nucleus is 

 not seen in the cervical and lumbar swellings. 



Cells of lateral cornu. These are only obvious 

 in the thoracic region, they are medium to small cells 

 elongated in the direction of the lateral cornu. 



3. Sections of 2nd or 3rd cervical, lower part of 1st thoracic, 

 and 1st or 2nd lumbar segments of man. Note in these that 

 the anterior cornu has no considerable lateral bulging as it has in 

 the cervical and lumbar swellings, but is larger than in the 

 mid-thoracic region. Note also 



In the 2nd or 3rd cervical segment ; Goll's column is distinct ; 

 the central canal is about way from the ventral surface ; a few 

 medium-sized cells, the cervical nucleus, are present in the region 

 of Clarke's thoracic nucleus ; one or two small bundles of large 

 nerve fibres of the spinal accessory are present either in the 

 grey substance close to the reticular area or running obliquely 

 outwards and dorsally from it (these may be seen in the first 5 

 or 6 cervical segments) ; the reticular area increases rapidly in 

 passing upwards in this region. 



