This bone, forming a considerable area of the face, and arching over the eye, is much exposed, and sometimes suffers fracture from one or another of the causes referred to above.

The fracture may involve that portion of the face situated between the eyes, or the orbital process which arches over them. The importance of fracture of this bone, whether in the one part or the other, is centred in the degree of displacement which attends it. Fracture without displacement in either case does not give rise to any serious symptoms unless the blow is high up and the brain suffers concussion.

A little swelling and drooping of the eyelid, and a blood-shot condition of the mucous membrane of the eye with a discharge of tears, may be all that is to be seen when the orbital process of the frontal bone is broken without displacement. In these cases but little requires to be done. A mild aperient, bran diet, and cold-water irrigation of the part will suffice to keep down local inflammation and assist repair. Where, however, the bone is depressed the eye will at the same time have suffered more or less damage, and the sooner the displaced bone is lifted into its place again the better. This may be effected by the employment of a bone lever and gentle continuous upward pressure, after which irrigation with cold water and a dose of physic are all that will be required.

Fracture of that part of the frontal bone between the eyes invariably occasions more or less injury to the frontal sinuses whose walls they assist in forming, and as these cavities communicate with the nostrils some blood-stained discharge may flow from them. If the force producing the fracture has been very considerable more or less depression of the broken pieces will have taken place, and it may be that the bone has been broken into several fragments. Any displacement should be remedied at once by levering up the depressed fragments. This will require that a small piece of bone shall be removed with a trephine from a suitable position outside the fracture area, and a lever properly padded at the point introduced into the opening and the depressed bone raised into its normal position. If the bone should be broken into small pieces replacement will be greatly assisted by manipulating them from the outside, while they are being raised by the lever from within. It may be that one or more of them will require to be removed. If so it should be done at once under strict antiseptic precautions; but it must be pointed out that since no muscles are attached here, and the bone is not exposed to any moving force, or called upon to support weight, there is nothing to occasion displacement when once adjustment of the broken parts has been effected.

Haemorrhage into the frontal sinuses is a common result of fracture of this part of the frontal bone, and should the operation of trephining be called for an opportunity will then be afforded for washing out the blood, for which a tepid antiseptic solution should be employed.

Chronic disease of the bone is an occasional consequence of this accident, and must be dealt with according to the indications of the case.