PHYSIOLOGICAL ANATOMY OF THE BULB 



599 



encephalon above, they present nodules of gray matter between the 

 fasciculi of fibres. 



External to the anterior pyramids, are the corpora olivaria. These 

 are oval and are surrounded by a distinct groove. They are white 

 externally and contain a gray nucleus 

 called the corpus dentatum. 



External to the corpora olivaria, are 

 the restiform bodies, formed chiefly of 

 white matter and constituting the postero- 

 lateral portion of the bulb. They are con- 

 tinuous with the posterior white columns 

 of the cord. The restiform bodies spread 

 out as they ascend, and pass to the cere- 

 bellum, forming a large portion of the 

 inferior peduncles. Some fibres from the 

 restiform bodies pass to the cerebrum. 



Beneath the olivary bodies and be- 

 tween the anterior pyramids and the 

 restiform bodies, are the lateral tracts of 

 the bulb, sometimes called the intermedi- 

 ary or lateral fasciculi, or the funiculi of 

 Rolando. These are composed of an in- 

 timate mixture of white and gray matter 

 and have a yellowish gray color. They 

 receive all that portion of the antero- 

 lateral columns of the cord which does 

 not enter into the composition of the 



. -I *"|-<1 11 1 



anterior pyramids. They usually are de- 



scribed as parts of the restiform bodies; the middle peduncle of the cerebei- 



. lum ; 7, anterior pyramids of the bulb; 



but they are peculiarly important, from 8, decussation of the anterior pyramids ; 



the fact that they contain the gray centres 9, olivary bodies; 10, restiform bodies; 



J * ii, arciform fibres; 12, upper extremity 



presiding over respiration; and for that of the spinal cord -, 13, ligamentum den- 

 reason they are here described as distinct ~; &%& t 



fasciculi. the optic nerves; 17, motor oculi com- 



~. . . , /r . ,. munis; 18, patheticus ; 19, fifth nerve; 



The posterior pyramids (funiculi gra- 20> motor oculi e xternus ; 21, facial 



Giles) are the smallest of all. They pass nerve : 22 - auditory nerve ; 23, nerve of 



Wrisberg; 24, glosso-pharyngeal nerve ; 

 Upward tO the Cerebellum, Without deCUS- 25, pneumogastric; 26, 26, spinal acces- 



sating, joining the restiform bodies above. ^ 2 ,?- subli "g al nerve '- 28 - 2 9. so, 



3 J cervical nerves. 



They are composed chiefly of white matter. 



As they pass upward in the bulb, they diverge, leaving a space called 



the fourth ventricle. 



The fourth ventricle is the cavity between the pons Varoiii, the 



. Anterior view of the bulb 

 (Sappey). 



i, infundibulum ; 2, tuber cinereum ; 

 albicantia; 4, cerebral pe- 

 5, pons Varoiii ; 6, origin of 



