260 



NERVOUS SYSTEM. 



THE NERVOUS SYSTEM. -Continued. 

 6th NERVE, Abducens (See ante, page 131). 



Origin. Same as 7th, 

 a gray nucleus in floor 

 of 4th Ventricle, 

 and 



lower border of Pons. 



6th Nerve, Abducens. 



Function , -[ ^tion to Ext. 

 I Rectus of Eye. 



Exit by sphenoidal fissure be- 

 tween the two heads of the 

 Ext. Rectus muscle of the 

 eye. 



No branches. 



8th NERVE, Auditory, OR PORTIO MOLLIS OF THE 7TH PAIR. 



Function Special Sense. 



Origin. Striae in floor 

 and anterior wall of 

 the 4th Ventricle, 



and 



winds around the 

 restiform body. 



8th Nerve. 

 Auditory. 



r 2 Semi-circ. canals. 

 Vestibular, toX Utricle. 

 t-Saccule. 



i Post. S.-C. canal. 

 Cochlear, to < Saccule Utricle Wall. 



(-Cochlea, and Organ of Corti. 



A nerve of special sense (hearing), fully described on page 225, ante. Its Exit ia 

 by the Internal Auditory Meatus, through the Internal Auditory Canal, to the internal 

 ear. It is the only cranial nerve which does not leave the cranial wall. 



I2th NERVE, Hypoglossal (NONUS OR 9TH OF WILLIS). 



Function, Motor of tongue, etc, 



(Gustatory of sth. 

 Sympathetic. 

 *,, i 

 i, 2, Cervical. 

 Vagus. 



Origin. Nucleus in 

 floor of 4th Ventricle, 



and 

 groove between the 



pyramidal and 



olivary bodies of 



the medulla. 



i2th Nerve, 

 Hypoglossal 



Descendens Noni> 



Br. to Sterno-hyoid. 

 Br. to Sterno-thyroid. 

 Br. to Omo-hyoid. 

 Joins Communicans 

 Noni Nerve. 



Thyro-hoid, to that muscle. 



(Stylo-glossus. 

 Hyo-glossus. 

 * i . -j 

 Genio-hyoid. 

 Genio-hyo-glossUs. 



Exit, by Ant. Condyloid foramen. 



