6 
DISEASES OF THE LIPS AND CHEEKS. 
been seen and operated on with varying success, depending on the kind 
and age of the tumour. 
Treatment consists in careful removal of the new growths, which is 
seldom very difficult if the knife is used early and boldly. 
(4.) PARALYSIS OF THE LIPS. FACIAL PARALYSIS. 
The facial is the motor nerve of the muscles of the ears, eyelids, nose, lips, 
and cheeks. Arising from the pons, it enters the inner ear with the N. 
acousticus, passes through the Fallopian canal, and outwards through the 
stylomastoid foramen of the petrous temporal bone, penetrates the parotid 
gland, and then passes over the posterior border of the lower jaw, on the 
external surface of which it divides. According to their points of origin, the 
following three portions may be differentiated. 
I. In the Fallopian canal arise : 
(1) A nerve for the stapedius muscle. 
(2) A nerve for the chorda tympani. 
II. At the stylomastoid foramen : 
(1) The posterior auricular nerve giving twigs to the cervico auricu- 
lares, and the parieto auricularis externus and internus. 
(2) The middle auricular, distributed to the skin lining the interior of 
the ear. 
III. Thence to the point of termination : 
(1) Nerve to the occipito-styloid, stylo-hyoid', and digastricus muscles. 
(2) The zygomatico temporalis nerve gives off— 
(a) The anterior auricular nerves. 
(b) Twigs to the temporalis muscle. 
(c) Twigs to the orbicularis palpebrarum and the external levator 
palpebrarum. 
(3) The cervical branch, which gives off motor twigs to the depressor 
of the ear and the superficial cervical muscles, afterwards passes 
over the external surface of the lower jaw, and, as a motor 
nerve, supplies the muscles of the nose, lips, and cheeks. 
Paralysis of the facial nerve occurs rather frequently in horses, but is 
rarer in oxen and dogs; it is commonly confined to one side, often to the 
nerve supply of the upper lip; the deformity consequently is slight, and 
the mischief may be overlooked. But double-sided paralysis interferes 
very noticeably with feeding, and therefore with nutrition, while at a 
later stage the respiration may become impaired owing to paralysis of 
the nostrils. 
The cause is most frequently external injury impairing the conductivity 
of the nerve. The malady is therefore common in horses suffering from 
such illness as colic or injuries to the feet, and which in consequence, lie 
a great deal. Siedamgrotzky first noted that this nerve often becomes 
bruised at the point where it winds round the lower jaw. The cheek- 
straps of the head-collar, and especially the buckle at the left side, may 
