83 



Glenoid Lobe 



Impression for 



flbro-Cartilagi- 



nous Ext. Aud. 



Meatus 



The base is a very definite but somewhat variable portion, the 

 most salient point of it being the Glenoid lobe on the extent of which 

 the form of the base considerably depends. In our cases, it certainly 

 never rose high enough to reach the Glenoid Fossa, though, it is sug- 

 gested that this may possibly be due to formalin contraction. In this 

 we confirm Parsons (1) and Symington (3). 



Behind this tongue-shaped glenoid lobe lies a deep wide groove, 

 the direction of which is from within outwards, downwards and 

 forwards. This is caused by the 



anterior and inferior walls of the stenson's Duct, 



cartilaginous external auditory 

 meatus. 



We have thought it proper 

 from our investigations to describe 

 this impression upon the base 

 rather than on the posterior sur- 

 face (e. f. Parsons & Symington 

 loc. cit.). The direction of this 

 groove is what one would expect 

 from the general direction of the 

 Pars Media of the External Au- 

 ditory Canal as described by 

 HowDEN (4) (see also fig. 801, 

 GuiBE (10). The general shape 

 of the base as seen from above 

 is triangular, with the apex of the 

 triangle forwards, though there is 



a marked approach towards the quadrangular owing to the change in 

 the inner border of the gland in its upper part, to be. described below. 

 The base as it is traced forwards beyond the Glenoid lobe, becomes 

 much narrower and ends in a thin border which lies in relation to 

 the Zygoma and is continuous with the upper edge of the facial 

 process, and socia parotidis. 



The postero-internal surface is flat from above downwards, 

 concave from side to side, and is definitely marked by three im- 

 pressions, an external, middle, and an internal. The external is 

 narrow and almost flat, and is caused by the contact above of the 

 lower portion of the Mastoid process and below of the anterior border 

 of the Sterno-Mastoid muscle. A salient border separates the mastoid 



6* 



Fig. 2. Base of right parotid gland, 

 seen from above. 



