not always. On puncturing and aspirating, the characteristic clotting fluid is obtained. If cholesterin crystals are found, it indicates a retention cyst. Evacuation relieves the symptoms, sometimes permanently, sometimes transiently. When the contents are purulent, a rapid but only apparent cure results from a single irrigation, but a permanent result can be obtained only by evulsion of the cyst-wall through a sufficiently large opening.

Of an entirely different nature are dental or follicular cysts. They are made up of a thin bony capsule, often containing an included tooth. The fluid is turbid and viscid or even purulent. They are of slow growth, but ultimately lead to distention of the antrum and bulging of one or more of its walls. Follicular dental cysts and tumors are the only lesions which are positively known to cause distention of the antrum walls. The other symptoms are usually vague. The treatment consists in removal of the entire capsule with chisel and bone forceps through an opening in the canine fossa.

CHAPTER VIII.

DISEASES OF THE FRONTAL SINUS, ETHMOID CELLS, AND SPHENOID SINUS.

INFLAMMATION OF THE FRONTAL SINUS.

54. Acute inflammation of the frontal sinus, less common than acute disease of the maxillary cavity, is a well-defined clinical occurrence. During a coryza or after an influenza or some general systemic infectious disease. (typhoid fever or erysipelas) it starts with slight fever and pain over the brow, the latter sometimes very severe. There may be more or less continuous dull browache, with spells of sharp, supra-orbital neuralgia. Often there is transient edema of the upper eyelid. There is always tenderness to touch over the brow and on the upper wall of the orbit. The disease is mostly onesided. Either at once or within a few days there occurs a profuse purulent discharge from that side of the nose, sometimes with relief of the pain. Of course, there is some nasal stuffiness, especially if there is a complicating diffuse nasal catarrh. Acute frontal sinuitis heals in most instances within from two to three weeks, but without adequate treatment an unknown proportion of cases become chronic. Even after apparent cure, occasional later relapses are not uncommon. The diagnosis, complications, and treatment can be discussed under one heading for acute and chronic disease.

55. Chronic inflammation of the frontal sinus is usually the prolongation of an acute attack. In other instances it begins insidiously. Its occurrence is favored by septum deflection and hypertrophies in the middle nasal meatus, the latter themselves often a result of sinuitis. The disease is sometimes wholly latent, and indicated only

by purulent discharge. Usually subjective symptoms are added whenever an acute coryza occurs. In most instances more or less suffering is constantly present. This may be dull or sharp frontal headache, usually but not invariably one-sided, when the sinuitis is one-sided, which is the more common occurrence. More characteristic is supra-orbital pain in attacks, sometimes of remarkably punctual periodicity. Mental irritability, depression, inability to concentrate the attention, more rarely dizziness, may be complained of. There is commonly tenderness over the brow and along the upper wall of the orbit. Occasionally puffiness of the upper eyelid is seen.

The discharge is variable in amount, and is sometimes retained for a few days on account of swelling in the infundibulum. When temporarily confined, it may or may not cause suffering, which may be suddenly relieved by the reappearance of the flow. When profuse, the flow is fairly continuous during the erect posture. The The pus is not always fetid, rather less often than in the case of maxillary empyema. The mucous membrane around the infundibulum underneath the middle turbinal is mostly swollen. During acute sinuitis this swelling is due to edema. Later on polypoid hypertrophy of the edges of the hiatus semilunaris is common. When there is much discharge, chronic rhinopharyngitis usually results. The effects of pus-formation and swallowing of pus upon digestion and nutrition are sometimes seen when the suppuration is profuse.

56. Distention of the walls of the sinus, especially bulging of the thin roof of the orbit, is an occasional symptom. This may occur very slowly, but sometimes increases rather suddenly. The contents in this case are either a viscid, slightly turbid mucus, or a mucopurulent fluid, but usually not pure pus. In some instances they have been found bacteriologically sterile. While it has been usually assumed that the accumulation of contents and the resulting distention depended on occlusion of the frontal duct, it has been shown recently (Avellis) that at

least in some of these cases the lesion is not at all primary disease of the frontal sinus, but a closed mucocele or empyema of an ethmoid cell intruded into the frontal sinus. After a slow growth for a long time, such a mucocele may finally perforate into the orbit.

The severest cases are those in which caries of the bony walls leads to perforation. This happens rarely in the first acute attack, more commonly during a later acute exacerbation. The least serious, but also the least frequent, perforation is through the anterior wall, causing an external fistula. More common and more important is the breaking-down of the orbital wall. The escape of

pus into the orbit may lead to diffuse phlegmonous inflammation and may even cause extension into the cranial cavity, with fatal results. In more fortunate cases a circumscribed orbital abscess results, which may open at the upper inner angle of the orbit. A most serious but relatively rare accident is caries of the posterior wall of the sinus, resulting in intracranial disease in the form of a subdural or cerebral abscess or a diffuse meningitis or thrombosis of the longitudinal sinus. Further diagnostic references regarding pyogenic intracranial affections can be found in the chapter on Intracranial Complications of Middle-Ear Disease.

Frontal sinuitis causes ocular disturbances quite frequently. Asthenopic discomfort from the use of the eyes. and insufficiency of convergence are frequent functional. disturbances. Constriction of the visual field has been observed. When distention of the orbital wall occurs, the eyeball is displaced laterally and its mobility may be interfered with. The most serious consequences may ensue in case of perforation into the orbit. Thrombosis. of the retinal vein, optic neuritis, and, later on, atrophy have been observed, although such complications are

rare.

57. The lesions in the frontal sinus are principally inflammatory edema during the acute stage. The chronic form depends mostly on hypertrophy of the mucous.

membrane. In more serious cases the bony walls become involved, at first by the formation of osteophytes, but in severe infections later on by caries. Perforation seems to occur especially along the channels of exit of the sinus. veins, which become thrombosed. When the walls are gradually distended, the process is one of bony absorption on the inner side, with deposition of fresh bony lamellæ under the external periosteum. The passage-way from the frontal sinus to the infundibulum is probably never or rarely closed permanently, but sometimes temporarily occluded at its nasal end by swelling or hypertrophy of the mucous membrane. In many instances inflammation of the frontal sinus is complicated by suppuration of one or more of the most anterior of the ethmoid cells, which may communicate with the frontal sinus or intrude into it.

The diagnosis of frontal sinuitis is suggested by the external signs, when present-viz., supra-orbital neuralgia, tenderness, especially along the inner upper wall of the orbit, edema of the lid or bulging of the sinus wall. Pain and tenderness without other symptoms are not sufficient to establish the diagnosis. They may be due to true supra-orbital neuralgia or to hysteria with some form of asthenopia. Mucocele without discharge can be recognized only when bulging occurs. The discharge of frontal sinuitis is found issuing underneath the middle turbinal. It may be difficult to distinguish between inflammation of the frontal sinus, the ethmoid cells, and maxillary antrum by means of the nasal symptoms. Maxillary disease must first be excluded by translumination or exploratory puncture. An effort should be made to pass a probe through the frontal opening. A flexible silver probe is bent at an obtuse angle about 3 cm. from its end, and the intranasal part may be slightly curved, with convexity toward the external side. After cocainization the probe is to search underneath the front end of the middle turbinal until it finds a passage leading upward and forward. When it has been pushed in by gentle manipulation to the extent of 3 cm., it is either in