5(;g 



THE CRANIAL NERVES. 



crosses over the external carotid below the digastric muscle. Above 

 the hyoid bone it is crossed by the lower part of the stylo-hyoid muscle 

 and posterior belly of the digastric, and rests on the hyo-glossus muBcle. 

 At the anterior border of the hyo-glossus it is connected with the gusta- 

 tory nerve, and is continued in the fibres of the genio-hyo-glossus 

 muscle beneath the tongue to the tip, distributing branches upwards to 

 the muscular substance. 



The principal branches of this nerve are distributed to the muscles 

 ascending to the larynx and hyoid bone, and to those of the tongue ; a 

 few serve to connect it with some of the neighbouring nerves. 



Fi-. 



Fig' 350. — View of the Distribution of the Spinal Acckssory and Hypoglossal 

 Nekves (from Sappey after Hirschfeld and Leveill^). ;^ 



1, lingual nerve ; 2, pneumogastric nerve ; 3, superior laryngeal (represented too 

 large) ; 4, external lar^-ngeal branch ; 5, spinal accessory ; 6, second cervical ; 7, third ; 

 8, fourth ; 9, origin of tlie phrenic nerve ; 10, origin of the branch to the subclaviii.s 

 muscle ; 11, anterior thoracic nerves ; 12, hypoglossal nerve ; 13, its descending branch ; 

 14, communicating branch from the cervical nerves ; 15, 16, 18, 19, descending branches 

 from the i)lexiform union of these nerves to the sterno-hyoid, sterno-thyroid, and omo- 

 hyoid muscles ; 17, branch from the descendens noni to the upper belly of the omo-hj-oid 

 muscle ; 20, branch from the hypoglossal nerve to the thyro-liyoid muscle; 21, communi- 

 cating twigs from the hypoglossal to the lingual nerve ; 22, terminal distribution of the 

 hypoglossal to the muscles of the tongue. 



