PRACTICAL CONSIDERATIONS: ACCESSORY AIR-SPACES. 1427 



becomes oedematous and is thrown into folds which later are obstructive ; {d) foreign 

 bodies (as a carious tooth, in the case of the antrum) have little chance for escape, 

 and mucous cysts, polyps, and lesions of the sinus walls (pyogenic, syphilitic or 

 tuberculous caries or necrosis) are not uncommon ; {e) one cavity may be infected 

 from another, pus from the frontal sinus entering the ethmoidal cells, or pus from 

 either of these entering the antrum through its normal opening, or through a 

 perforation of its wall in the vicinity of the infundibulum (Lack). 



In the greater number of cases, the chief — often the only — symptom of chronic 

 suppuration of the accessory sinuses, is a purulent nasal discharge. Spontaneous 

 recovery is practically impossible, and in the great majority of cases, operation — for 

 disinfection and drainage — becomes necessary. The cavities (as one may act as a 

 reservoir of pus coming from another) may have to be attacked in a definite order. 

 Ordinarily it is possibleto determine whether the pus comes from the sinuses that open 

 into the same passage within the middle meatus — the anterior group — or from those 

 which open more posteriorly, above the middle turbinate bone — the posterior 

 group. If no definite evidence can be obtained as to which of the anterior group is 

 involved, it would be well to attack first the antrum, then the ethmoidal cells, and 

 then the frontal sinus. If the posterior group is affected it is usually proper to 

 remove the posterior portion of the middle turbinate and open the posterior ethmoidal 

 cells, later, if necessary, opening the sphenoidal sinus. Occasionally, as in oziena 

 (on account of the width of the inferior meatus and the atrophy of the inferior and 

 middle turbinates), the opening of the sphenoidal sinus can be seen from the front, 

 and then this sinus may be explored first (Lack). 



The frontal sinuses do not appear as distinct spaces until about the seventh 

 year, and are developed by a separation of the two tables of the skull, with more 

 or less resulting prominence above the superciliary ridges. There may be a 

 greater relative bulging toward the interior of the cranium, so that the prominence 

 of the superciliary ridges is no indication of the size of the cavities of the sinuses. 

 They are often very irregular in size, one being larger at the expense of the other, 

 the septum deviating to one or the other side accordingly. It is therefore, difficult, 

 at times, to decide which side is involved by disease. 



Fracture of the skull over a frontal sinus does not imply that the cranial cavity is 

 opened, even when depression exists. The frequent presence in these fractures of em- 

 physema within the orbit and in the subcutaneous tissue, results from the entrance of air 

 through the communication with the nose, when the latter is blown. The dependent 

 position of its opening into the middle meatus or the infundibulum, provides better 

 drainage for discharges than is the case in the other sinuses, and probably accounts for 

 the relative infrequency of empyema of this sinus, although this ad\'antage is partly off- 

 set by the length, narrowness, and tortuosity of the canal, which render it easily liable 

 to obstruction. Swelling of the' mucous lining of the outlet of the frontal sinus may 

 thus occlude the canal, and result in abscess (empyema). If this remains undrained the 

 pus would tend to burrow through the weakest point of the wall, which usually leads it 

 through the floor of the cavity into the orbit, giving rise to an orbital cellulitis, and to 

 displacement of the eyeball. It later tends to escape through the inner portion of the 

 upper eyelid. In some cases it extends through the posterior wall of the sinus into 

 the cranial cavity, causing a septic meningitis, or an extradural or brain abscess. 



Extensive necrosis of the frontal bone may follow sinus disease, as the frontal 

 diploic vein, which empties into the frontal vein at the sujDraorbital notch, receives 

 blood from t^e sinus. 



If free drainage is maintained these complications are very rare, but if drainage 

 is defective it is imperative to open the sinus early. This may be done externally, 

 the anterior wall being removed by a chisel or trephine. The incision may be verti- 

 cal or along the superciliary ridge from the inner end to the supraorbital notch, 

 sometimes dividing the supraorbital vessels. The thinness of the nasal portion of 

 the floor of the sinus is marked — as well as that of the orbital portion — and therefore 

 frontal sinus suppuration is, as a rule, associated with infection of some of the anterior 

 ethmoidal cells, which— surgically — may perhaps be considered as forming a part 

 of that sinus (Lack), although Kiimmel notes that he has seen the ethmoidal cells 

 perfectly intact in a series of cases of frontal sinusitis. 



