THE SALIVARY GLANDS. 299 



of the duct. Enlarge the opening with the probe of the tracer, and 

 insert a beaded bristle or a canula for injection. Inject as directed 

 for Wharton's duct (§ 775). 



§ 777. Exposure of the Salivary Glands and their Ducts.— 

 Divide the skin as follows :— (A) Along the mesal border of the 

 mandibular raTnus from the canine tooth directly caudad as far as 

 the caudal end of the larynx. (B) From the caudal end of the 

 incision (A) to a point opposite the meatus auditorius externus. 

 (C) From the maxillary canine to the dorsal border of the ear. (D) 

 Along the edge of the lips fi-om the mandibular to the maxillary 

 canine, leaving a narrow band of skin with the lip. 



Exposure of the Olands, etc. — Commence at the angle next the 

 larynx (ventro-caudal angle) and dissect the skin free. Use a sharp 

 scalpel and dissect close to the skin. Then commence at the same 

 point and dissect free the thin dermal muscle (§ 608) in the same 

 manner that the skin was dissected. It is necessary to take the 

 greatest care in removing the muscle in order to avoid injury to 

 nerves and vessels. Remove the caudal part first, thus exposing 

 the glands and larger vessels and nerves, which are more easily seen 

 than their branches. Compare the appearances presented with 

 those shown in Fig. 67. If the gland ducts were injected with fine 

 mass, the glands wiU be of the same color as the mass used. The 

 duct of the parotid (Fig. 87) will be very conspicuous and will serve 

 as a kind of landmark. The same is true of the V. jugularis (Fig. 

 87, 101). 



In exposing and isolating nerves and vessels in this preparation, 

 it is necessary to work with the greatest care. The sharp tracer 

 cannot be used as safely as in most cases. Use the dull tracer, fine 

 forceps and scissors, and remove fat and connective tissue piece- 

 meal. So many branches of the nerves enter the dermal muscle 

 that it is necessary to dissect it very carefully, so as not to remove 

 at the same time the larger branches of the nerves. 



Explanation of Fig. 87.— A. fac, A. facialis.— Facial artery; 

 a branch of the carotid. Ductus Stenon. (Stenonianus).— Stenon's 

 duct ; duct of the parotid gland. Glandula parotis.— The parotid 

 gland, the largest of the salivary glands. Gl. (Glandula) submax- 

 illaris.— The submaxillary gland. Gl. m., Glandula molairis.— 

 Molar gland. Mandible. — Inferior maxilla, lower jaw. M. civ. 

 (clavo-) trapezius (Fig. 66). M. sterno-mstd. (mastoideus) (Fig. 



