146 



MR HAROLD AXEL HAIG ON THE 



C. Lumbar region. (Text-fig. 3.) 



The three main subdivisions of each lateral crescent of grey matter can be dis- 

 tinguished, viz. posterior, intermedio-lateral, and anterior horns. 



A few nerve-cells are present about the middle of the posterior horn, and a well- 

 marked group is to be seen at the base of the posterior horn (Clarke's column). 

 Groups also occur at the tip of the intermedio-lateral horn, and to the number of three 

 in the anterior horn, these being very obvious and the component cells very large. 



H 



n. 



FIG. 3. A transverse section of the spinal cord (lumbar region). Lettering as in figs. 1 and 2, except : 



d.m. Dura mater. 

 p.r.b. Posterior root- bundles. 

 a.r.b. Anterior root-bundles. 



n. Bundles of the candii equina. 



v. Large branches of the vertebral vessels. 



The posterior or grey commissure is wide, and the anterior white commissure is 

 relatively broad in the antero-posterior direction : the central canal appears as a 

 four-sided space lined by an ependyma possessing an internal layer of ciliated 

 epithelium. 



The posterior root-bundles are very large and number three or four on each side 

 posteriorly, lying between the dura mater and the pial investment of the cord ; the 

 anterior bundles are two in number on each side antero-laterally. 



Of the white matter, the lateral columns are of fairly wide extent, as also are the 

 anterior columns ; there is no marked distinction between Goll's and Burdach's columns 

 posteriorly, although a small pial septum does show the superficial division. 



(ROY. soc. EDIN. TRANS., VOL. XLVIII., 854.) 



