During the four-year period 1954-1958, the roentgenological and morphological studies of the paranasal sinuses in Korean cases has been carried. In the studies, also, sex ratio and age distribution were considered.

I. Frontal Sinuses : 1) 500 cases, 327 male and 173 female cases, of the morphological study has been done. 2) The size of the sinus with P-A view X-ray film shows larger in left than right side, and wider in base than upper part of the sinus with lateral view. 3) 89 per cent of the cases had more than two sinuses, in which 9 per cent of them are symmetric, and unilateral of the single sinus without a septum shows 1.8 per cent of total number of the cases. 4) A number of the sinus chambers would be classified as follows. 2 sinuses;86.6 per cent, 3 sinuses;10.7 per cent, 4 sinuses;2.1 per cent, 5 sinuses;0.4 per cent, 6 sinuses;0.2 per cent. 5) 80 per cent of the cases had the sinus-septum which were not always same as straight. Straight;54.5 per cent, deviation to left;24.5 per cent, deviation to right;15.0 per cent, others;6.0 per cent. 6) The shpae of the sinus with P-A view may be classified in irregular ten groups. It is found that the commonest of such groups are moderate types as formed as the gingkoleaf (28.2 per cent), and next in order of frequency were nostril types (23.4 per cent), vertical types (13.0 per cent), horizontal types (12.8 per cent), and the others (22.6 per cent).

II. Maxillary Sinuses : 1) 561 cases, 363 male and 198 female cases, of the morphological study was carried. 2) In all of the cases, the maxillary sinuses had one chamber as single sinus on each side except only three cases were multiple, and in which 78.2 per cent of them was symmetrically formed. 3) The size of the sinuses with P-A view X-ray film would be classified as 70.4 per cent of the medium, 15.0 per cent of the large, and 14.6 per cent of the small, and the comparison of both side of the maxillary sinuses revealed as follows. left=right;76.5 per cent, leftright;10.1 per cent. 4) The comparison of lower border of the maxillary sinus and the proper nasal cavity was that 62.4 per cent of the maxillary sinus shows lower than base of the nasal cavity, 32.6 per cent of the cases are parallel, and 5.0 per cent of them was higher. 5) The commonest shape of the maxillary sinus with P-A view was up-side wide pyramid form (52.4 per cent), and the others were down-side wide (42.4 per cent), horizontal (4.0 per cent), and the multiple (1.2 per cent). 6) The lateral view in all cases of the maxillary sinuses shows only one type of the sinus as a square as wider at the roof and the posterior face.