The facial nerve may also be implicated in that rare type of basic fracture which was described by Lèon Boullet in 1878, under the title of ‘Fracture of the Mastoid portion of the Temporal bone’. This fracture is fully described on [p. 108]. It will suffice to mention that the mastoid process may be torn away from the base of the skull, the facial nerve being lacerated as it descends the aqueductus Fallopii.
Bilateral facial paralysis is exceedingly rare. Two cases were described by the late Professor von Bergmann. Its occurrence is pathognomonic of the typical basic fracture (see [p. 84]).
A
B
Fig. 41. To show the Relation of Basic Fractures to the Petrous Bone. A shows the course pursued by an antero-posterior fracture of the petrous bone. Note that it lies external to the internal auditory meatus. B shows—enlarged—the inner aspect of the outer fragment. Note the relation of the fracture to the semicircular canals, and that the membrana tympani and ossicles are quite uninjured.
Complete facial paralysis may be associated with the following symptoms:—
Epiphora, conjunctivitis, and keratitis (from paralysis of the orbicularis palpebrarum).
Loss of taste (from involvement of the chorda tympani).