1346 



A MANUAL OF ANATOMY 



Each half of the bulb presents two grooves — ^ventro-lateral and 

 dorso-lateral. The ventro-lateral sulcus is situated between the 

 pyramid and the olivary body, and along this sulcus the funiculi 

 of the hypoglossal nerve emerge in line with the ventral roots of 

 the spinal nerves. Whilst, however, the latter are spread over a 

 certain area, the hypoglossal funiculi emerge along a straight line 

 corresponding to the ventro-lateral sulcus of the bulb. The ventro- 

 lateral sulcus is not represented on the surface of the spinal cord. 

 The dorso-lateral sulcus is serially continuous with the dorso-lateral 

 sulcus of the spinal cord, and it lies on the dorso-lateral aspect of 

 the olivary body. Along this sulcus, in order from above down- 

 wards, there are (i) the funiculi of the glosso-pharyngeal nerve, 



Corpus Albicans 

 Mesial Root of Optic Tract . 



Optic Commissure 



; _ Optic Nerve 

 Infundibulum, 

 Tuber Cinereum . .j i , Optic Tract 



Third Nerve 





Lateral Root of Optic Tract /\ 

 External Geniculate BodyX. J 



Locus Perforatus Posticus 



Sixth Nerve ^^^^f 



Facial Nerve _^^~'-'^ 

 Pars Intermedia of Wrisberg 

 Auditory Nerve _ 



/ Glosso-pharyngeal Nerve,. 

 Pneumogastric Nerve 



Superficial Arcuate Fibres 



Spinal Accessory Nerve — 



First and Second Cervical Nerves 



Fourth Nerve 



Motor Root of Fifth Nerve 



Sensory Root of Fifth Nerve 



Middle Peduncle of 

 Cerebellum 



Restiform Body 

 .., Hypoglossal Nerve 

 ...Anterior Median Fissure 



IjJL Decussation of the Pyramids 



Fig. 562. — The Medulla Oblongata, Pons Varolii, and iNTERrEDONcrLAu 



Region. 



C.C, Crus Cerebri ; P., Pyramid ; O.B . Olivary Body. 



(2) the funiculi of the pneumogastric or vagus nerve, and (3) the 

 funiculi of the bulbar part of the spinal accessory nerve. These 

 nerve-funiculi are in line with the dorsal roots of the spinal nerves. 



The bulb in its lower half contains a prolongation of the central 

 canal of the spinal cord. This part of the bulb is spoken of as the 

 closed part, and it extends as high as the level of the calamus 

 scriptorius. In the upper half of the bulb the central canal opens 

 out at the level of the calamus scriptorius into the fourth ventricle, 

 and the dorsal aspect of the bulb forms the lower or bulbar half 

 of the floor of the fourth ventricle. The upper half of the bulb is 

 therefore spoken of as the open part. 



The surface of each half of the bulb is divided into three areas by 



