) 
q i 
THE FACE. 1173 
reached as it enters the inferior dental canal: the lingual nerve, which les a lttle 
anterior to the inferior dental, can be exposed through the same opening. 
The facial nerve, after emerging from the stylo- mastoid foramen, is imbedded 
in the parotid gland where it is superficial to the external carotid artery ; the 
nerve can be rolled under the finger as it crosses the posterior border of the ascend- 
ing ramus of the jaw at the lev el of the lower margin of the tragus; incisions con- 
tinued alc mg the ramus above this point should be. only skin deep if the nerve is 
to be avoided. To expose the trunk of the nerve an incision is made from the 
anterior border of the mastoid process to the angle of the jaw. Incisions upon the 
cheek should, whenever possible, be planned so as to run parallel with the branches 
of the nerve; these radiate from the lower end of the tragus. The nerve may 
be paralysed by wounds of the cheek and by malignant tumours of the parotid, 
also by intracranial and middle-ear lesions. 
The parotid gland is surrounded by a fascial envelope, the strongest portion of 
which is continued from the deep cervical fascia over its superficial aspect to 
become attached to the zygoma (Fig. 647); hence abscesses in the parotid tend 
to burrow deeply towards the pterygo-maxillary space and the upper part of the 
pharynx; the pus should therefore be evacuated by Hilton’s method, through 
an early incision over the angle of the jaw. A study of the relations of the eland 
explains the surgical difficulties which attend its complete removal. 
The parotid duct can be rolled beneath the finger as it crosses the masseter, 
rather less than a finger’s breadth below the zygoma. After winding over the 
anterior border of the muscle 1t soon pierces the buccinator, and opens into the 
mouth opposite to the second molar tooth of the upper jaw. The level and direc- 
tion of the duct may be marked out upon the surface by drawing a line from the 
lower margin of the concha to a point midway between the ala nasi and the angle 
of the mouth. 
Superficial to the parotid and a little in front of the tragus is the pre-auricular 
lymphatic gland, which is frequently found to be inflamed in children suffering from 
eczematous conditions of the eyelids, face, scalp, and external ear. In opening 
an abscess connected with this gland care must be taken to make the incision as 
low down as possible, so as to avoid the parotid duct. 
Eyelids.—The skin of the eyelids, more especially of the upper, is very thin and 
connected with the orbicularis muscle by delicate and lax subcutaneous tissue 
destitute of fat; hence the marked swelling which occurs in a “black eye” and in 
cedema of the lids. Along the anterior edge of the free margins of the lids are the 
eyelashes and the orifices of the sebaceous glands, suppurative inflammation of 
which gives rise to a “stye”; along the sharp, posterior edge of the free margins 
are the minute orifices of the Meibomian glands. These clands, imbedded in the 
deep surface of the tarsal plates, are seen through the palpebral conjunctiva as a 
row of parallel, yellowish, granular-looking streaks. From the deep position of the 
glands it follows that the skin over a Meibomian cyst is freely movable, and that 
to reach the cyst an incision should be made through the conjunctival surface of 
the lid. 
The palpebral conjunctiva is closely adherent to the ocular surface of the tarsal 
plates; at the fornix it is loose and contains small lymphoid follicles, which 
become hypertrophied in the condition known as granular conjunctivitis. The 
ocular conjunctiva is thin, transparent, and loosely attached to the sclerotic, so 
that in operating upon the eye a fold of the membrane can be picked up with 
forceps to steady the eyeball. 
In inflammatory affections of the eye the state of those vessels which are visible gives 
important information as to the seat of the mischief. For example, in inflammation of 
the conjunctiva the posterior conjunctival vessels (derived from the palpebral arteries), 
searcely visible normally, appear as a close network which fades away towards the corneal] 
margin ; these vessels move freely with the conjunctiva, and do not disappear under pres- 
sure. In superficial inflammations of the cornea the anterior conjunctival vessels (the 
most superficial of the terminal branches of the anterior ciliary arteries) are seen to 
spread in a freely branching manner into its superficial layers. In ¢rit/s and deep inflam- 
mations of the cornea there is a pink cireumcorneal zone of vascular dilatation consisting 
