Dissection of Sheep's Head. 225 



MylO'hyoid muscle should he next dissected away* from its 

 superior margin, and reflected downwards towards the middle 

 line. In order to do this, the Mylo-hyoid nerve will have to 

 be cut across by the fracture of the jaw, and turned over 

 with the muscle. Excessive care will he needed along the pos- 

 terior margin of the muscle, in the line hetween the last upper 

 molar and the duct of the Suhmaxillary Gland, beneath which 

 runs the Chorda tympani, and is located the anterior 

 fraction of the Submaxillary ganglion. Just within the 

 posterior- superior corner of the same muscle, and overlapped 

 by the anterior margin of the (internal) Pterygoid above 

 described, may be seen the broad white stem of the Gustatory 

 Kerve. Close within the median raphe of the Mylo-hyoid 

 above noted is lodged the submaxillary duct, in the middle of 

 its course ; and between the two branches of the gustatory 

 nerve is situated the long sublingual gland, whose duct runs 

 forwards a little above the Whartonian duct. 



The terminal course of that branch of the Facial nerve 

 called the Chorda tympani, is alone here brought into view. 

 It has descended between the two Pterygoid (external and 

 internal) muscles, and met the Gustatory nerve. It should 

 be carefully dissected out, and will be seen again to quit the 

 Gustatory nerve, and working backwards and downwards on 

 the segment of a circle, to join the direction of the Sub- 

 maxillary duct, in company with which we have noted it in a 

 previous dissection. A reddish ganglionic mass may be made 

 out in the fat about one-eighth of an inch in advance of the 

 lower fifth of the Chorda ; this is the anterior Suhmaxillary 

 ganglion. From this ganglion filaments radiate ; one larger 

 filament going back to the Submaxillary gland and forward 



* We must here again caution the Student to be extremely cautious'to remove 

 only the muscle, and leave the inter-muscular adipose tissue to investigate when 

 the superjacent muscle is reflected. 



G G 



