SUBMAXILLARY REGION 291 



Musculus Genioglossus. This is a flat triangular muscle, 

 the medial surface of which is in contact with its fellow of 

 the opposite side in the median plane. It arises by a short 

 pointed tendon from the upper mental spine on the posterior 

 aspect of the symphysis of the mandible, and from this its 

 fleshy fasciculi spread out in a fan-shaped manner. By far 

 the greater part of the muscle is inserted into the tongue by 

 an insertion which extends throughout the whole length of 

 the organ from the tip to the base ; below the tongue, a 

 few fibres reach the side of the pharynx. The genio-glossus 

 is supplied by twigs from the hypoglossal nerve. 



Arteria Lingualis. As the lingual artery is now fully 

 exposed, it can be conveniently studied at this stage. 

 It springs from the anterior aspect of the external carotid, 

 and is separable into two parts viz. (i) a part extending 

 from its origin to the posterior border of the hyoglossus 

 muscle; (2) a part lying in relation to the upper border of 

 the hyoid bone and extending to the anterior border of the 

 hyoglossus, where it divides into two terminal branches, the 

 sublingual and the deep artery of the tongue. 



The first part has been fully examined in a previous 

 dissection. It lies in the carotid triangle of the neck, and 

 is therefore comparatively superficial. It is crossed by the 

 hypoglossal nerve, and lies, medially, against the middle 

 constrictor. The second part proceeds anteriorly along the 

 upper border of the great cornu of the hyoid bone, and 

 is covered by the hyoglossus muscle, which intervenes 

 between it and the hypoglossal nerve. The nerve, how- 

 ever, is placed at a slightly higher level. The deep or 

 medial relations of the artery in this stage of its course 

 are the middle constrictor of the pharynx and the genio- 

 glossus. 



The branches of the lingual artery are : 



1. Suprahyoid from \hefirst part (p. 233). 



2. Dorsalis linguae from the second part. 



3. Sublingual. 



4. Profunda. 



Rami Dor sales Lingua. The dorsalis linguae is generally 

 represented by two or more well-marked branches, which 

 pass upwards, under cover of the hyoglossus muscle, to end 

 in twigs to the mucous membrane covering the pharyngeal 

 part of the dorsum of the tongue. Some twigs are supplied 



ii 19 



