628 PHYSIOLOGY. 



Lying external, but adjacent, to the column of Goll is another 

 tract which is a continuation of the column of Burdach. It is the 

 funiculus cuneatus. 



As previously stated, the upper, expanded portion of the gracilis 

 nucleus has been termed the clava ; the upper portion of the cuneatus 

 is known as the cuneate tubercle. Both prominences are caused by 

 underlying masses of gray matter. 



The scriptorial half of the floor of the fourth ventricle is divided 

 into two lateral halves by a longitudinal groove. In each half can 



Cga 



Fpy 



Fig. 243. Cross-section of the Oblongata through the Decussation of 

 the Pyramids. (After HENLE.) 



Fpy, Pyramidal tract. Cga, Anterior horn. Fa', Remnant of anterior 

 column. Ng, Nucleus funiculi gracilis. g, Substantia gelatinosa. XI, Nervus 

 accessorius. 



be seen three small prominences whose general shape is somewhat 

 Jri angular. The first one, a triangle of white color, is the trigonum 

 hypoglossi; it covers the nucleus of origin of the hypoglossus nerve. 

 The second one, trigonum vagi and the continuation of the head of 

 the anterior horn, corresponds to the nuclei of the ninth, tenth, and 

 eleventh cranial nerves. It is the ala cinerea. The third eminence, 

 the trigonum acustici, covers the nucleus of the eighth nerve. 



