DISSECTION OF THE SUBMAXILLARY REGION. 97 



the depressor of the angle of the mouth. It gives branches to the muscles 

 below the aperture of the mouth, and communicates with the facial nerve; 

 but the greater part of the branch is directed upwards beneath the depressor 

 labii inferioris, and is distributed on the inner and outer surfaces of the 

 lower lip. 



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 labial branch. 



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

 ends in the bone: it lies beneath the canine and incisor teeth, to which it 

 furnishes twigs. 



The labial branch, issuing by the labial foramen, ramifies in the struc- 

 tures covering the lower jaw, and communicates with the branches of the 

 facial artery. 



The GUSTATORY or LINGUAL NERVE ( 8 ) is the remaining trunk of the 

 inferior maxillary, and is concealed at first, like the others, by the exter- 

 nal pterygoid muscle. It is then inclined inwards with a small artery 

 over the internal pterygoid muscle, 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 submaxillary region. 



In this course under the jaw the nerve does not distribute any branch 

 to the parts around, but the following communicating branch is received 

 by it. 



The chorda tympani is a branch of the facial nerve, and is distributed 

 to the tongue. Escaping from the tympanum by the Glaserian fissure, 

 this small branch (*) is applied to the gustatory nerve at an acute angle. 

 At the point of junction some fibrils communicate with the gustatory, but 

 the greater part of the chorda tympani is conducted along that nerve to 

 the tongue. 



The origin of the nerve, and its course across the tympanum to its posi- 

 tion beneath the external pterygoid, are described in SECTION 14. 



SECTION VII. 



SUBMAXILLARY REGION. 



THE submaxillary region is situate between the lower jaw and the hyoid 

 bone. In it are contained the muscles of the os hyoides and tongue, the 

 vessels and nerves of the tongue, and the sublingual and submaxillary 

 glands. 



Position. In this dissection the position of the neck is the same as for 

 the examination of the anterior triangle. 



Dissection, If any fatty tissue has been left on the submaxillary gland, 

 or on the mylo-hyoid muscle, when the anterior triangular space was dis- 

 sected, let it be taken away. 



The submaxillary gland (fig. 16, u ) lies below the jaw in the anterior 



part of the space limited by that bone and the digastric muscle. Its shape 



is irregular, and the facial artery winds over the surface. It rests on the 



mylo-hyoideus, and sends a deep process round the posterior or free border 



7 



