The ophthalmic division of the fifth nerve is rarely injured to such a degree as to cause anæsthesia of all the regions supplied. Blood extravasation into the surrounding regions, or direct involvement of one of the branches of the nerve, often results in areas of anæsthesia, and some few cases have been recorded in which there was complete anæsthesia of both cornea and conjunctiva, with subsequent ulceration and sloughing. The nasal nerve may be implicated as the result of a fracture involving the cribriform plate, whilst the supra-orbital and supra-trochlear branches may be damaged by fractures of the vertical plate of the frontal bone.
The third nerve is similarly liable to injury, in any part of its orbital course. It is quite exceptional, however, for the whole trunk to be affected, some of the branches being taken, others left. The fourth nerve is also occasionally involved, generally in association with other orbital nerves.
When anæsthesia or paralysis of muscles results from pressure exercised on the nerves by extravasated blood, the ultimate prognosis is not unfavourable. When due to direct implication, in the line of the fracture, the prognosis is much more uncertain, partial or complete loss of function resulting.
SYMPTOMS POINTING TO FRACTURE OF THE MIDDLE FOSSA
External hæmorrhages.
(a) Hæmorrhage into the temporal region.
The extravasated blood may either be confined to the temporal region—temporal hæmatoma—or diffused throughout the subaponeurotic space. A temporal hæmatoma is always highly suggestive of a fracture involving the temporal fossa, especially in the event of marked outward bulging, with stretching and discoloration of the overlying tissues. In many cases also the hæmatoma pulsates, in which case it can be presumed that the fracture of the temporal fossa is associated with hæmorrhage from a lacerated middle meningeal artery (see [Fig. 38]). In such cases the application of pressure to the hæmatoma may lead to the development of fits on the contra-lateral side, originating in the face or arm regions and spreading to the higher cortical motor area.
A
