may be so extensive that marked forward protrusion of the globe exists. The time at which proptosis makes its appearance, and the degree to which it progresses, vary according to the nature of the lesion. Thus:—
| Proptosis severe, appearing almost at once, | implies | a fracture associated with injury to the cavernous sinus or internal carotid artery. |
| Proptosis moderate, and appearing after a few hours, | „ | a fracture involving the walls of the orbit, the blood being derived from lacerated ethmoidal and other small vessels. |
| Proptosis appearing days or weeks after the accident, usually progressive, | „ | a fracture involving the region of the sphenoidal body and complicated by the formation of a fistulous communication between the cavernous sinus and the carotid artery (see [Traumatic orbital aneurysm]). |
(d) Retinal hæmorrhages.
Fleming, in 1902, reported 12 cases of fracture of the skull, all except one being fractures of the base, in which retinal hæmorrhages were present. All cases were associated with hæmorrhage into the subarachnoid space, and when this hæmorrhage was of a unilateral nature the retinal changes were likewise one-sided. It was also found that in 4 cases of cerebral hæmorrhage without osseous lesion retinal hæmorrhages were present in three, these three being all associated with considerable effusion into the subarachnoid space.
These observations are not only of value in the general diagnosis of intracranial lesions, but are also of considerable importance in the differential diagnosis between extra- and intradural hæmorrhages.
(e) Hæmorrhage from the nose and mouth
is almost invariably present in fractures of the anterior fossa, with the inference that the fracture involves the cribriform plate. The blood—derived mainly from lacerated ethmoidal vessels—escapes from the anterior nares or, passing back into the naso-pharynx, escapes by the mouth or is swallowed, to be vomited up later.
Escape of cerebro-spinal fluid.
Blandin, of the Hôtel-Dieu, drew attention to this condition in the year 1840. The fracture involves the cribriform plate of the ethmoid, and is associated with laceration of the overlying dura mater and arachnoid, and of the prolongations of those membranes along the olfactory nerves.
The escape of cerebro-spinal fluid from the nose may be regarded as diagnostic of a fracture of the anterior fossa, in spite of the fact that Goucard, Malgaigne, and others describe cases in which, as the result of a severe fracture of the petrous bone (middle fossa) without laceration of the membrana tympani, the fluid escaped along the Eustachian tube to be expelled by mouth and nose.