PAROTID REGION. 



903 



which arise from it, and passes down between 

 the styloid process and the pterygoid muscles, 

 so as to come in contact with the pharynx and 

 the internal carotid artery, as well as the in- 

 ternal jugular vein, and the eighth, ninth, and 

 sympathetic nerves. A portion of the gland 

 passes with the internal maxillary artery be- 

 tween the ramus of the jaw and the internal 

 lateral ligament; it here comes into contact 

 with the inferior maxillary nerve, and some- 

 times reaches the space between the external 

 and internal pterygoid muscles. 



In addition to the relations here pointed out 

 to the parts by which it is surrounded and 

 limited, the parotid has important relations to 

 vessels and perves which pass through its sub- 

 stance or are deeply imbedded within and 

 beneath it. 



Arteries. The external carotid artery passes 

 into the lower border of the gland near its 

 deep surface; as it ascends it becomes more 

 superficial, and is continued upwards under 

 the name of the superficial temporal, which 

 passes up between the ear and the articulation 

 of the jaw, crosses over the zygoma, and so 

 emerges from beneath the parotid gland and its 

 fascia. 



The internal maxillary artery passes off 

 from the carotid at right angles. At its origin 

 it is imbedded in the substance of the parotid, 

 and is nearly on a level with the lower extre- 

 mity of the lobe of the ear; it bends down- 

 wards and inwards, and escapes from the pa- 

 rotid by passing between the ramus of the jaw 

 and its internal lateral ligament. 



The transversalis Jaciei arises from the ca- 

 rotid or from the superficial temporal artery at 

 a variable distance between the angle and neck 

 of the jaw. Its origin is imbedded in the 

 substance of the parotid ; it then goes upwards 

 and forwards, and passes out beneath the ante- 

 rior border of the gland, lying between it and 

 the masseter muscle. 



The posterior auricular artery is a small 

 branch of uncertain origin. When regular it 

 arises from the external carotid, above the di- 

 gastric and stylo-hyoid muscles, opposite the 

 point of the styloid process ; it is here partly 

 concealed by the parotid gland, in the posterior 

 part of which it is imbedded ; it then passes 

 upwards and backwards between the ear and 

 the mastoid process. While this artery is im- 

 bedded in the parotid it sends off a small 

 stylo-mast old branch, which passes upwards 

 to enter the stylo-mastoicl foramen. In ad- 

 dition to the above-mentioned arteries there 

 are several branches variable in their number, 

 size, and situation, which pass off from the 

 carotid and its branches and are distributed to 

 the substance of the parotid gland. 



Veins. The veins corresponding to the ter- 

 minal branches of the external carotid artery 

 accompany the arteries and are consequently 

 imbedded in the parotid gland. The temporal 

 and internal maxillary veins unite and form a 

 common trunk, which lies superficial to the 

 external carotid artery. This common trunk 

 receives the posterior auricular and the trans- 

 verse facial veins, as well as some veins from 



the substance of the parotid, and so the com- 

 mencement of the external jugular vein is 

 formed. There is also a communicating branch 

 which passes through the parotid gland from 

 the internal to the external jugular vein ; this 

 branch may be looked upon as one of the 

 origins, and in some cases it is the chief origin 

 of the external jugular vein. 



Nerves. We have next to study the rela- 

 tions of the nerves which are found in the 

 parotid region. 



The nerve which lies most superficially in 

 this region is the great auricular, some small 

 branches of which lie superficial to the parotid 

 fascia and are distributed to the skin of the 

 parotid region, while other branches pierce the 

 fascia, and pass through the parotid in a di- 

 rection forwards and upwards to be distributed 

 on the skin of the cheek. The nerve then 

 sends off two branches, the superficial auri- 

 cular and the deep auricular. 



The superficial auricular branch of the great 

 auricular nerve passing vertically upwards in 

 the dense fibrous tissue which connects the 

 parotid with the skin, reaches the inferior part 

 of the concha, and is distributed to the skin of 

 the ear. 



The deep auricular branch passes through 

 the substance of the parotid, to place itself in 

 front of the mastoid process, crossing at an 

 acute angle the auricular branch of the facial 

 nerve, which is deeper than it, and with which 

 it anastomoses by a branch of considerable size. 

 The nerve then passes backwards and divides 

 into branches which are distributed to the ex- 

 ternal ear, and to the skin over the occipital 

 region. 



The auricula-temporal nerve arises from the 

 trunk of the superior maxillary by two por- 

 tions, between which passes occasionally the 

 middle meningeal artery. It passes backwards 

 beneath the external pterygoid muscle, and 

 between the internal lateral ligament and neck 

 of the jaw ; it then divides into two branches, 

 a superficial or temporal and a deep or auri- 

 cular branch. The superficial temporal passes 

 up between the ear and the articulation of the 

 jaw, crossing the root of the zygoma, and be- 

 coming superficial above the parotid gland ; it 

 then supplies the skin of the temple and side 

 of the head. In its course this nerve sends off 

 one or two branches which communicate with 

 the portio dura nerve ; it also sends branches to 

 the tempero-maxillary articulation and to the 

 external auditory meatus. The auricular branch 

 forms a plexus behind the neck of the jaw and 

 around the internal maxillary artery ; it then 

 divides into several branches, some of which 

 pass through the parotid to be distributed on 

 the external ear, while others anastomose with 

 branches of the cervical plexus, particularly 

 with the great auricular nerve. One branch 

 joins the dental nerve just before it enters the 

 dental canal, and another passes into the tem- 

 pero-maxillary articulation. 



The portio dura nerve passes out of the 

 stylo-mastoid foramen and enters the substance 

 of the parotid gland. At its exit from the 

 foramen the nerve sends off three small branches, 



