LABORATORY MANUAL OF PHYSIOLOGY. 



and the intervening portion excised. Clean the masseter and di- 

 gastric muscles of cellular tissue. Avoid irjury to the facial artery 

 and the gland duct which lies between it and the masseter muscle. 

 Carefully separate the digastric muscle from the artery, and tie the 

 branch which supplies the muscle. Divide the digastric and mylo- 

 hyoid muscles and, being careful to avoid injury to the structures 

 beneath, turn the muscle flaps back. 



The submaxillary gland should also be gently drawn upward 

 and backward. The following structures will now be exposed to 

 view: 



In front of the posterior insertion of the digastric and in front of 

 and below the reflected gland, the carotid artery is seen. Crossing 

 this is the hypoglossal nerve, H (see Fig. 36), and running along 



FIG. 36. Dissection of Submaxillary Region, Dog. (After Bernard.) G, Sub- 

 maxillary gland ; /, jugular vein ; C, carotid artery ; //, hypoglossal nerve ; L, lingual 

 nerve ; T, chorda tympani ; >, ducts of submaxillary and sublingual glands (S) ; 

 Dg; digastric muscle ; M, mylo-hyoid muscle. 



with the artery are filaments of the sympathetic nerves. Entering 

 into and passing out of the hilum of the gland are seen the chorda 

 tympani nerve branch to the gland, the branch of the facial artery 

 to the gland, and the gland duct. 



Beneath the reflected mylo-hyoid muscle is seen the lingual 

 nerve (Fig. 36, L). Trace this nerve to the ramus of the jaw. At 

 this point a small branch will be exposed which, in close proximity 



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