The interest in disease of the sinuses in infants and children prompted us to attempt the investigation of the maxillary antrum. For this purpose, we have successfully employed a small cannula (fig. 1) which enters the natural orifice of the cavity in infants. The cannula is 3 inches (7.6 cm.) long and is of a small bore. At the distal end it is curved at right angles to the shaft. The curved arm is approximately three-eighths of an inch (0.9 cm.) in length. The cannula is a miniature of the one devised for adults by Dr. Sidney Yankauer.
Although the antrum in an infant is small, the natural opening is relatively large. The hiatus semilunaris can be seen in the infant cadaver as a rather broad gutter, at the posterior extremity of which is found the ostium of the antrum. Because of the flexibility of the soft structures of the