54 SURGICAL ANATOMY OF 



border of the raraus of the jaw ; behind, the mastoid 

 process of the temporal bone, the cartilage of the ear 

 and the edges of the sterno-mastoid and digastric mus- 

 cles ; above, the zygomatic arch ; and below, an imagi- 

 nary line drawn horizontally backwards and inwards 

 from the angle of the jaw to the styloid process, by the 

 stylo-hyoid and stylo-maxillary ligaments, and the pro- 

 cess of cervical fascia passing from the sterno-mastoid to 

 the jaw. The dimensions of this region 'obviously vary 

 with the several movements of the lower jaw ; more- 

 over, there are certain differences in its size with respect 

 to the age of the individual ; thus, in the infant, the re- 

 gion is broader in proportion below, on account of the 

 obliquity of the jaw and the non-development of its 

 angle, and bulges externally, on account of the quantity 

 of fat and lymphatics contained within it ; again, in old 

 age, in the edentulous state, the base of the region be- 

 comes broader, owing to the falling forward of the jaw. 



Dissection. On removing the integument covering 

 the parotid gland, it will be seen to be enveloped in an 

 incomplete capsule derived from the cervical fascia 

 which separates it from neighboring structures. 



The relations and connections of the parotid gland are, 

 externally and superficially the lymphatics, the platysma 

 myoides, some few branches of the superficial cervical 

 plexus, and the integument; anteriorly, the posterior 

 border of the ramus of the jaw, the external and inter- 

 nal pterygoid muscles, between which lies a process of 

 the gland ; inferiorly and posteriorly, the mastoid pro- 

 cess, the sterno-mastoid, posterior belly of digastric, 

 styloid muscles, transverse process of atlas, internal 

 jugular vein, internal carotid artery, eighth pair of 



