618 



DISSECTION OF THE PTERYGOID REGION. 



and facial 

 nerve. 



Inferior 

 dental 



is between 

 pterygoid 

 muscles, 



then in the 



and supplies 



branch to 

 mylo-hyoid, 



dental 

 branches to 

 grinding 



and cutting 

 teeth, 



branch to 

 lower lip. 



Dental 

 artery 

 has an 



incisor and 



labial 

 branch. 



Lingual 

 nerve 



courses to 

 the tongue : 



no branch 

 here. 



Chorda 

 tympani 

 joins 

 lingual, 



filaments pass between the otic ganglion and the beginning of the 

 auriculo-temporal nerve. 



/. Branches to the facial nerve. Two considerable branches pass 

 forwards round the superficial temporal artery to join the upper 

 trunk of the facial nerve. 



The INFERIOR DENTAL ( 7 ) is the largest of the branches of the 

 inferior maxillary nerve. In its course to the canal in the lower 

 jaw, the nerve is placed behind and external to the lingual, 

 and lies at first beneath the external pterygoid muscle ; it after- 

 wards rests on the internal pterygoid, and near the dental foramen 

 on the internal lateral ligament. After the nerve enters the 

 bone, it is continued forwards beneath the teeth to the foramen 

 in the side of the jaw, and ends at that spot by dividing into an 

 incisor and a mental branch. Only one offset (to the mylo-hyoid 

 muscle) leaves the dental nerve before it enters the bone. Its 

 branches are : 



a. The mylo-hyoid nerve arises near the dental foramen, and is 

 continued along a groove on the inner aspect of the ram us of the 

 jaw to the cutaneous surface of the mylo-hyoid, and to the anterior 

 belly of the digastric muscle. 



6. The dental brandies arise in the bone, and supply the molar 

 and bicuspid teeth. If the bone is soft, the canal containing the 

 nerve may be laid open so as to expose these minute branches. 



c. The incisor branch is small and continues the direction of the 

 nerve onwards to the middle line, furnishing offsets to the canine 

 and incisor teeth, below which it lies. 



d. The mental or labial branch which issues on the face beneath 

 the depressor of the angle of the mouth has been described on 

 page 564. 



The INFERIOR DENTAL ARTERY, after entering the lower jaw, has 

 a similar course and distribution to the nerve. Thus it supplies 

 offsets to the bone, dental branches to the molar and bicuspid teeth, 

 and ends anteriorly in an incisor and a mental branch. 



The incisor branch is continued to the symphysis of the jaw, 

 where it ends in the bone ; it furnishes twigs to the canine and 

 incisor teeth. 



The mental branch, issuing by the mental foramen, ramifies in 

 the structures covering the lower jaw, and anastomoses with the 

 branches of the facial artery. 



The LINGUAL or GUSTATORY NERVE ( 8 ) is concealed at first, like 

 the others, by the external pterygoid muscle. It is then inclined 

 forwards with a small artery over the internal pterygoid, and under 

 cover of the side of the jaw to the tongue. The remainder of 

 the nerve will be seen in the dissection of the stibmaxillary region 

 (p. 623). 



In its course beneath the jaw the nerve does not give off any 

 branches, but the following communicating nerve is received by it. 



The chorda tympani ( 6 ) is a branch of the facial nerve, and 

 leaves the tympanum by a special aperture close to the inner end 

 of the Glaserian fissure. Appearing from beneath the upper 



