Other instruments may be commended for the free opening of the sinus, such as the author's or Hajek's hook, Lack's cutting forceps, etc. The disadvantage of most instruments is that, unlike my cutting forceps, they cannot be used until the middle turbinal has been partially ablated, on account of their size.

In order to get a free opening in the sinus, Hajek advocates the removal of the posterior ethmoid cells on the affected side, and in many cases this is very desirable, though not always necessary however. The difficulty is, not to make an opening in the anterior wall, but to prevent its more or less rapid closure, hence the advantage of the large opening that Hajek's method presents.

Even after free removal of the anterior wall, there is a great tendency for cicatrization to occur, so that the removed wall may seem to have been replaced by a new one in which a minute opening may be seen.

H. PFAU BERLIN NW.7.

Fig. 138. The author's small up-cutting sphenoidal sinus forceps for removing remains of the anterior wall. Down-cutting forceps are also used.

This difficulty is diminished if, in addition to the anterior wall, the anterior portion of the floor of the sinus is removed and also the thick lower bony border of the anterior wall near its junction with the floor.

The opening having been established, irrigations are made daily with some mild alkaline or antiseptic solution previously warmed.

With free drainage established, the sphenoidal sinus disease usually improves rapidly. But in some patients free irrigation and drainage fail to cure, owing to the polypoid degeneration of the lining mucosa. It is then necessary to curette with gentleness and great caution the floor and posterior wall, bearing in mind the risks that attend such a procedure. Gently swabbing the sinus walls with a solution of nitrate. of silver, 10 to 40 gr. to the fluid ounce, may be used advantageously in chronic intractable cases.

The dangers to be avoided in puncturing the cavity are perforation

of the thin walls of the sinus. Injury to the internal branch of the spheno-palatine artery (see page 12) might cause troublesome hæmorrhage, but this can be controlled by tampons. A consideration of the anatomical relations of the sinus will suffice to demonstrate the dangers of surgical interference unless most cautiously performed, for apart from the great variations in the size and development of the cavities and the thickness or thinness of the walls, there are often present the added dangers of softening of the thin walls due to the disease. Hence no one who is unaccustomed to deal with nasal affections would be justified in attempting these procedures, and every expert rhinologist would observe the utmost caution in their performance.

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SECTION XIV.

MUCOCELES OR BONE CYSTS IN THE NASAL
ACCESSORY SINUSES.

ETIOLOGY and Pathology-Mucoceles or bone cysts are fairly common in the ethmoidal labyrinth, especially in connection with the middle turbinated bone, but similar distention of the frontal sinuses and maxillary antra are met with. Probably their relative frequency in the ethmoidal cells is due to several causes the greater secreting activity and richer glandular supply of the lining mucosa, as compared with that of the frontal sinuses and maxillary antra, their much smaller apertures of exit, and, perhaps above all, their more direct exposure and liability to catarrhal inflammation. Ethmoidal mucoceles are due to progressive distention of one or more cells from the pressure of retained secretion, owing to more or less complete and prolonged obstruction of their apertures or ostia. Probably frontal sinus mucoceles are originated in this manner. But with the antrum of Highmore the pathology of cystic distention is more open to question, and it is very doubtful whether closed antral mucocele ever arises from simple accumulation of the secretion and distention of its walls, a condition formerly described as "hydrops antri," "hydrops inflammatorius," or "dropsy of the antrum." Logan Turner, in his contribution to the pathology of bone cysts, states that “there is no doubt that many cases have been described as cystic distention of the antrum in which the true nature of the case, namely, the encroachment into the antrum of a cyst of dental origin, has not been recognized. Killian appears to accept the occurrence of true distention of the antrum. . . . Zückerkandl has dealt with this question, and considers that distention of the antrum from an accumulation of serous fluid is outside the range of discussion. . . . Clinical experience goes to show that it is in the region of the canine fossa or facial wall that expansion most frequently takes place " (that is, the strongest, not the weakest walls the cavity), "thus affording further proof of the dental origin of the

cyst in these cases." There is little room for doubting that cystic expansion of the antral walls is almost invariably due to the growth. of cysts arising in connection with the teeth. (See Plates XXXVII and XXXVIII.)

In rare instances of enlargement of turbinal cells or a frontal sinus, constituting clinically a bone cyst, the cavity contains nothing but air. Such cysts are either mucoceles from which the fluid contents have escaped, or are examples of over-development of otherwise normal cavities.

Bone cysts of the accessory cavities may be classified into three varieties according to their contents: (1) The smaller number, in which the cavity contains nothing but air; (2) The largest number, which contain mucin or clear serous fluid, very frequently with cholesterin crystals; and (3) Those which have mucopurulent or purulent contents, these latter being probably instances where the mucous contents have become invaded by pyogenic organisms.

Bony Cysts of the Middle Turbinate.-Bone cells normally exist in the middle turbinate about once in every four or five persons, and when one or more such cells are abnormally developed nasal symptoms may arise. The normal turbinate cell may become distended with secretion from occlusion of the ostium, originating a true mucocele, and occasionally the contents become purulent from secondary infection. (See Plate XXVIII.)

Symptoms. The most usual symptom is progressive nasal obstruction, and on examination the nasal passage is more or less completely occluded by a tumour extending forwards and downwards from the region of the anterior end of the middle turbinal. As it develops it often pushes the septum over to the opposite side, thus aggravating