682 



DISSECTION OF THE TONGUE. 



Expose the 



carotid 



artery. 



The CAROTID CANAL. Dissection. The student should now com- 

 plete the exposure of the internal carotid artery in the temporal bone 

 by chipping away the outer wall of the canal, taking the artery 

 a guide. In cleaning the artery large, and rather red, branches of 

 the superior cervical ganglion of the sympathetic will be seen if the 

 part has been well kept ; and, in a fresh part, a small filament from 

 the tympanic branch of the glosso-pharyngeal may be seen to join the 

 sympathetic at the posterior part of the canal, and another from 

 the Vidian at the fore part. 



The INTERNAL CAROTID ARTERY IN THE TEMPORAL BONE. The 



artery has a winding course in the bone ; at first it ascends in front 

 of the cochlea and tympanum ; next it is directed forwards and 

 inwards almost horizontally ; and, lastly, it turns upwards into th 

 cranium through the foramen lacerum. Branches of the sympathetic 

 nerve and a venous plexus surround the vessel in the bone. 



SECTION XIV. 



Directions. 



Dissection. 



Tongue : 



form juid 

 situation ; 



relations of 

 apex, and 

 base. 



Upper 

 surface : 



body ; 

 root. 



DISSECTION OF THE TONGUE. 



Directions. The tongue and larynx are to remain connected with 

 each other while the students learn the general form and structure 

 of the tongue. 



Dissection, The ends of the extrinsic lingual muscles that have 

 been detached may be shortened, but enough of each should be left 

 to trace it afterwards into the substance of the tongue. 



The TONGUE is an ovoid, somewhat flattened body, with tin- 

 larger end turned backwards, which occupies the floor of the mouth, 

 and forms a part of the anterior wall of the pharynx. It is free 

 over the greater part of its surface ; but at the back, and at the 

 posterior two-thirds of the under surface, it is attached by muscles 

 and mucous membrane to the parts around. 



The tip of the tongue touches the incisor teeth. The base is 

 attached to the hyoid bone, and is connected likewise with the 

 epiglottis by three folds of mucous membrane a central and two 

 lateral. 



The upper surface or dor sum is convex, and in the anterior two- 

 thirds of its extent is marked by a medium longitudinal groove or 

 raphe, which terminates behind in a depression of variable depth, 

 named the foramen ccecum. From the depression a slight lateral 

 groove is directed outwards and forwards 011 each side for a short 

 distance. The part of the tongue in front of the lateral grooves is 

 distinguished as the body, and is received into the hollow of the roof of 

 the mouth ; its surface is covered with papilhe. The posterior third 

 or root of the organ looks into the pharynx ; and its surface is 

 smoother, although rendered somewhat irregular by projecting 

 mucous glands and groups of lyrnplioid follicles, and by small 



