1498 A MANUAL OF ANATOMY 



or motor nucleus. In accordance with this view, the nucleus con- 

 tains two sets of cells — sensory and motor — some of the afferent 

 glosso-pharyngeal and most of the afferent vagal fibres terminating 

 in arborizations around the sensory cells, and some of the efferent 

 fibres of each nerve arising as the axons of the motor cells. 



The nucleus of the fasciculus solitarius is a nucleus of termination, 

 or sensory nucleus. 



The fibres of the pars intermedia of Wrisberg or sensory portion 

 of the facial nerve terminate in the upper part of the nucleus of the 

 fasciculus solitarius. 



The efferent or motor fibres of the glosso-pharyngeal and vagus 

 nerves arise as the axons of the motor cells of the ventral vago- 

 glosso-pharyngeal nucleus, or nucleus ambiguus, which is a nucleus 

 of origin, or motor nucleus. According to the description which 

 has been given of this nucleus, it gives origin to all the motor fibres 

 of the two nerves. If, however, the dorsal vago-glosso-pharyngeal 

 nucleus is a mixed nucleus, then some of the efferent or motor fibres 

 of the two nerves arise as the axons of its motor cells. 



The axons of the cells of the terminal sensory nuclei are disposed 

 like those of the cells of the terminal sensory nuclei of the fifth nerve. 

 They cross to the opposite side, become longitudinal, and ascend 

 in company with the mesial fillet or chief sensory tract to the optic 

 thalamus of the side to which they have crossed. They constitute 

 the vago-glosso-pharyngeal ascending thalamic tract. 



•Eleventh or Accessory (Spinal-Accessory) Nerve. — ^This is a motor 

 nerve, which is really a continuation of the pneumogastric or vagus. 

 Its fibres arise from the accessory nucleus (dorsal vago-accessory 

 nucleus), which is situated partly within the medulla oblongata or 

 bulb, and partly within the cervical part of the spinal cord. This 

 nucleus consists of a column of large cells which is continuous with 

 the dorsal vago-glosso-pharyngeal nucleus. The column extends 

 from the level of the lower part of the olivary body to the level of 

 the sixth cervical nerve. The bulbar portion of the nucleus is situ- 

 ated on the dorso-lateral aspect of the hypoglossal nucleus. The 

 spinal portion is situated in the lateral part of the anterior grey 

 cornu of the cervical spinal cord, and its cells lie directly behind 

 the motor cells which give origin to the anterior roots of the upper 

 five cervical nerves. 



The fibres which arise from the bulbar portion of the accessory 

 nucleus constitute the bulbar part of the accessory nerve, and are 

 accessory to the vagus nerve. The fibres which arise from the 

 spinal portion of the accessory nucleus constitute the spinal part of 

 the accessory nerve. 



Bulbar Part. — The fibres of this part arise as the axons of the cells 

 of the bulbar portion of the accessory nucleus. They are directed 

 at first dorsalwards, and then outwards through the lateral part of 

 the medulla oblongata or bulb, from which they emerge in the form 

 of about five funiculi, placed below, and in line with, the funicuH 

 of the pneumogastric nerve. They then pass outwards, lying within 



