umatic" variety, and
are attributed to exposure to cold. Others result from fractures
implicating the middle fossa of the skull, or are associated with
chronic suppuration in the middle ear.

In fractures passing across the petrous temporal, the nerve may be
torn at the time of the injury, or may become pressed upon by a
traumatic effusion or by callus later, but considering the frequency
of these fractures it is comparatively seldom damaged.

Suppurative disease of the middle ear is a more common cause of facial
paralysis. The nerve, as it traverses the facial canal (aqueductus
Fallopii), may be pressed upon by inflammatory effusions or
granulations, or may be destroyed by the suppurative process,
particularly in young children, as in them the osseous wall of the
aqueduct is very thin. It may also be involved in tuberculous and in
malignant disease of the middle ear.

The nerve may be injured also in the course of operations on the
mastoid or middle ear, or in the removal of tumours or glands in the
parotid region. As the nerve breaks up into numerous branches soon
after it leaves the stylo-mastoid foramen, the paralysis may be
confined to one or more of its branches.

Temporary paralysis may result from inflammatory conditions such as
parotitis, or from blows or pressure over the nerve, for example by
the forceps in delivery.

_Symptoms._--In complete unilateral _facial paralysis_ (Bell's
paralysis) the affected side of the face is expressionless and devoid
of voluntary or emotional movement. The muscles are flaccid, the cheek
is flattened and smooth, all its folds and wrinkles being
obliterated. When the patient speaks or smiles, the face is drawn to
the sound side (Fig. 201). The eye on the affected side cannot be
closed, and on making the attempt the eyeball rolls upwards and
outwards. The lower lid droops, the patient cannot wink, and the
conjunctiva therefore becomes dry, and is irritated by exposure to
cold and dust. The tears run over the cheek. From paralysis of the
buccinator muscle there is inability to whistle or to puff out the
cheeks and food collects between the cheek and the gums. The
orbicularis oris being also paralysed, the patient is unable to show
his upper teeth, and the labial consonants are pronounced
indistinctly. The sense of taste is often impaired from involvement of
the chorda tympani nerve.

[Illustration: FIG. 201.--Patient suffering from left facial
Paralysis. Note smoothness of