DISSECTION OF THE DOG 161 



the inferior alveolar vessels and nerve ; but the dissector will have an 

 opportunity later of examining these on the other side of the head. 



Note the presence of the mylo-hyoid nerve— a branch of the mandibular 

 nerve — and the subhngual vessels. 



Now turn the mylo-hyoid muscle downwards as far as possible. 



Glandtjla submaxillakis. — The submaxillary gland is a rounded, yellow- 

 ish object, placed between the digastric muscle and the wing of the atlas 

 on a level slightly deeper than that of the parotid gland. While being the 

 least distinctly lobulated of all the sahvary glands, the submaxiUary, in 

 consequence of a strong fibrous capsule, is the most definite in form. 

 _ In contact with the lateral surface of the gland are the narrow, ventral 

 end of the parotid, the inferior auricular and cutaneous muscles, the cervical 

 branch of the facial nerve, and the superficial branch of the second spinal nerve. 

 This surface, moreover, is not infrequently traversed by a shallow groove in 

 which the internal maxillary vein is lodged. The medial surface is moulded 

 upon the sterno-cephahc and digastric muscles. 



The submaxillary duct (ductus submaxLUaris [Whartoni]) leaves the medial 

 surface of the gland and crosses the surface of the digastric muscle under 

 cover of the sublingual gland. Then, accompanying the larger sublingual duct 

 over the stylo-glossal muscle, it finally opens into the mouth on a poorly 

 marked elevation — the sublingual caruncle (caruncula sublingualis) — by the 

 side of the frsenulum of the tongue. 



Glandula sublingualis. — The subhngual gland is elongated, narrow, 

 reddish in hue, and stretches from the submaxillary gland, with which it 

 is in intimate contact, to about the level of the third premolar tooth. Two 

 parts are readily distinguished : (1) a larger, thicker aboral portion; and (2) 

 a much smaller, thin and narrow, oral part. 



The aboral portion (gl. subungualis grandicanalaris) lies between the 

 digastric, pterygoid, and masseter muscles and a part of the mandible. Its 

 duct (ductus subhnguahs major) runs along the surface of the stylo-glossal 

 muscle, in company with and somewhat dorsal to the submaxillary duct, 

 in common with which it opens into the mouth. 



The feebly developed oral portion of the subhngual gland (gl. subungualis 

 parvicanalaris) hes between the mylo-hyoid muscle and the mucous membrane 

 of the mouth, and is occasionally slightly overlapped by the aboral portion, 

 from which it can only be distinguished by its slightly paler colour. The 

 lingual nerve crosses the lateral surface of this part of the sublingual gland 

 obhquely. There are several (eight to twelve) smaUer sublingual ducts (ductus 

 subhnguales minores). 



Dissection. — Remove the submaxillary and sublingual glands and clean 

 the muscles, vessels, and nerves on the side of the tongue, pharynx, and 

 larynx. 



