THE HEAD AND NECK. 119 



dentally, I have verified in seven cases the views of the author of the follow- 

 ing : 



CONTINUED STUDY OF THE RELATIONS OF THE FRONTAL SINUS TO THE ANTRUM. 



BY THOMAS FILLEBROWN, M.D., D.D.S., BOSTON, MASS. 

 PROFESSOR OF OPERATIVE DENTISTRY AND ORAL SURGERY, DENTAL SCHOOL OF HARVARD UNIVERSITY. 



(Read before the American Dental Association, August j, 1897, and reprinted from the '''Dental Cosmos" for 



December, 1897.) 



" Last year I made a report of some observations I had made on the formation 

 of the infundibulum, showing that in many cases it continued directly to, and 

 terminated in the foramen of, the antrum, and that a fold of mucous membrane 

 mentioned by Merke, in 1834, extended above the foramen, forming a pocket, 

 from the bottom of which the opening into the antrum is situated, thus directing 

 any discharge coming down the infundibulum into the antrum, so that, under ordi- 

 nary circumstances, no abnormal discharge from the frontal sinus would escape 

 into the nasal passage until the antrum was filled so as to cause a backward 

 overflow. 



" I mentioned the fact that Tilleaux, about 1840, noticed that of fluid injected 

 into the frontal sinus, a great part flowed into the antrum, and that Dr. Cryer, in 

 the same year, mentioned the same circumstance. He also showed that a probe 

 could be passed from the antrum into the frontal sinus. I also noticed that 

 Byran had mentioned the fact of occasional communications between the cavities, 

 but considered them anomalies, and that Professor Harrison Allen had discussed 

 the proliferation of empyema of the frontal sinus into the antrum. These obser- 

 vations were of isolated cases, and were not proved or considered indicative of 

 the normal anatomy of the parts. 



" I reported that the examination of eight different subjects showed that the 

 infundibulum continued as a deep groove, or tube, open on one side down to the 

 foramen of the antrum, and terminated in it, in every one of the eight cases, and 

 that the pocket described was present in seven of the eight. This seemed to 

 imply that the continuation of the infundibulum to the antral foramen and the 

 presence of the pocket membrane was the normal formation. During the past 

 winter I had opportunity to examine fifteen heads in the Harvard dissecting- 

 room, and found the infundibulum continuing to the foramen of the antrum in 

 every case. The membranous fold was present in every case, except on the left 

 side of one subject. In this case the process was broad and flattened toward the 

 meatus, and, though the mucous fold was absent, the widened process served the 

 same purpose, as it formed a cup-shaped cavity quite as capacious as the pocket 

 on the other side. 



" In another case the mucous fold was thickened and had considerable mus- 

 cular tissue intermingled in its substance. 



" On the right side of this subject the infundibulum was very large, and in 

 place of the ordinary foramen there were two openings, both quite large, fully 

 one-fourth of an inch in diameter. 



" In another case the pockets were large, irregular in form, and deep, the 

 mucous fold completely covering the infundibulum from the foramen of the 

 frontal sinus to the antrum. 



" In one subject the mucous fold was considerably calcified. This condition 

 had obtained to a degree throughout the whole system. This subject was 

 advanced in years. This makes a total of twenty-three cases ; a number, I think, 

 sufficient to establish the fact of the normality of the anatomy of the parts. 



" The very few variations only prove the rule. I hoped to secure the co-opera- 



