DISSECTION OF THE HEAD AND NECK 367 



TRIGEMINAL NERVE (N. TRIGEMINUS). 



(A) Motor part (portio minor). 



Nuclei originis : 



(a) Principal motor nucleus (nucleus motorius princeps N. trigemini) 



in pars dorsalis pontis. 



(b) Lesser motor nuclei (nuclei motorii minores N. trigemini). 



(ba) Cells of locus caeruleus. 



(bb) Cells along descending or mesencephalic root (nucleus 



radicis descendentis ) . 



Cortical control: from lower third of gyrus centralis anterior and feet 

 of frontal gyri, through capsula interna and partly through basis 

 pedunculi (pyramidal tract), partly through area of lemniscus me- 

 dialis (accessory lemniscus of v. Bechterew). 



(B) Sensory part (portio major). 



Nucleus originis: semilunar ganglion (ganglion semilunare [Gasseri]). 

 Nuclei terminales: 



(a) Main sensory nucleus (nucleus sensibilis N. trigemini). 



(b) Nucleus of spinal tract (nucleus tractus spinalis N. trigemini). 

 Secondary paths : 



(a) To opposite medial lemniscus and through it to [ventro-] lateral 



nucleus of thalamus. 



(b) To substantia reticularis alba of same and of opposite side, and 



through it to [ventro-] lateral nucleus of thalamus. 



Tertiary path: from [ventro-] lateral nucleus of thalamus to central 

 gyri (somaesthetic area). 



ABDUCENT NERVE (N. ABDUCENS). 



Nucleus originis: nucleus of abducent nerve (nucleus N. abducentis) in 



pars dorsalis pontis. 

 Cortical control: 



(a) Pyramidal tract (*?). 



(b) " Accessory lemniscus" (?). 



(c) Indirectly through optic-acoustic reflex path. 



FACIAL NERVE (N. FACIALIS). 



Nucleus originis: nucleus of facial nerve (nucleus N. facialis) in ventral 



lateral part of pars dorsalis pontis close to medulla oblongata. 

 Cortical control: 



(a) Through pyramidal tract of the same and of the opposite side. 



(b) Through the "accessory descending lemniscus" of the same and of 



the opposite side (Hoche). 



INTERMEDIATE NERVE (N. INTERMEDIUS). 



Nucleus originis: geniculate ganglion (ganglion geniculi). 



Nucleus terminalis: probably the same as for N. vagus and N. glosso- 



pharyngeus. 

 Secondary path: uncertain. 



ACOUSTIC NERVE (N. ACUSTICUS). 



(A) Vestibular nerve (N. vestibularis) . 



Nucleus originis: vestibular ganglion (ganglion vestibulare) . 

 Nuclei terminales : 



(a) Lateral nucleus (nucleus N. vestibularis lateralis [Deitersi]). 



