96 SURGICAL APPLIED ANATOMY, tchap. vi. 



within the nose have managed to make their way to 

 the frontal sinuses. A case is reported where epis- 

 taxis, extending over many years, was due to an insect 

 (the pentastoma tfenioides) that had settled in. these 

 sinuses. One day it was sneezed out, and no further 

 bleeding occui'red (Med. Times, 1876). The last-named 

 parasite is said to be often met with in the frontal 

 sinus of the dog. The antrum exists at birth, but 

 attains its largest dimensions in old age. The walls of 

 the cavity are thicker in children than in adults. 

 Tumours of various kinds are apt to develop in this 

 cavity, and to distend its walls in various directions. 

 Thus the growth breaks through the thin inner wall 

 and invades the nose, it pushes up the roof of the 

 cavity and invades the orbit, it encroaches upon the 

 mouth through the floor of the antrum, and makes its 

 way also through the somewhat slender anterior wall 

 into the cheek. The densest part of the antrum wall 

 is that in relation to the malar bone, and this part 

 does not yield. There is little inducement for any 

 growth to spread backwards, although it sometimes 

 invades the zygomatic and pterygo-maxillary fossae. 

 As the infraorbital nerve runs along the roof of the 

 antrum, while the nerves of the upper teeth are con- 

 nected with its walls, these structures are pressed 

 upon in growths springing from the antrum, and 

 much neuralgia of the face and teeth often produced. 

 In tapping the antrum, a spot is usually selected just 

 above the second bicuspid tooth, since the bone is here 

 thin and is conveniently reached. In some cases it is 

 sufficient to extract a molar tooth, since the fangs of 

 these teeth often enter the cavity of the antrum. 

 The teeth usually selected are either the first or the 

 third molar. 



As the result of a fall, one of the upper teeth has 

 been entirely driven into the antrum and lost to view. 

 In one case, reported by Haynes Walton, an upper 



