88 SURGICAL APPLIED ANATOMY. [Chap. vn. 



gland. The obliquity of the ram us of the jaw in 

 infancy and old age causes the lower part of the space 

 to be, in the former instance relatively, and in the 

 latter instance actually, larger than it is in the adult. 

 The gland is closely invested by a, fascia derived 

 from the cervical fascia. The superficial layer of the 

 parotid fascia is very dense, is continuous behind with 

 the fibrous sheath of the sterno-mastoid, and in front 

 with that of the masseter. Above it is attached to 

 the zygoma, while below it joins the deep layer. The 

 deep layer is slender, is attached to the styloid process, 

 forms the stylo-maxillary ligament, and is connected 

 with the sheaths of the pterygoid muscles and the 

 pterygoid process. The gland is, therefore, encased 

 in a distinct sac of fascia, which is entirely closed 

 below, but is quite open above. Between the anterior 

 edge of the styloid process and the posterior border 

 of the external pterygoid muscle there is a gap in 

 the fascia, through which the parotid space communi- 

 cates with the connective tissue about the pharynx. 

 It is well known that in post-pharyngeal abscesses 

 there is very usually a parotid swelling, and in several 

 instances the pus, or at least some portion of it, has 

 been evacuated in the parotid region. In these cases 

 the matter most probably extends from the pharyngeal 

 to the parotid region, through the gap just described. 

 From the disposition of the fascia it follows that very 

 great resistance is offered to the progress of a parotid 

 abscess directly outwards through the skin. The 

 abscess often advances upwards to the temporal, or 

 zygomatic fossse, in the direction of least resistance, 

 although progress in that line is resisted by gravity. 

 It frequently makes its way towards the buccal 

 cavity or pharynx, or it may break through the 

 lower limits of the fascia and reach the neck. It 

 must be borne in mind that the gland is in direct 

 contact with the cartilaginous meatus, with the ramus 



