THE NASAL CAVITY. 53 



toward the base of the brain. The relation of the sinus to the internal carotid artery, which may 

 lead to fatal hemorrhage from the nose, has been already mentioned (see page 31). The opening 

 of the sinus into the nasal cavity is in the so-called spheno-ethmoidal recess, behind and above 

 the superior turbinated bone; the orifice of the sinus, as is the case in the antrum of Highmore, is 

 situated near its roof (see Fig. 19). 



The air-cells of the lateral masses of the ethmoid bone, which occupy the upper portion of the 

 outer wall of the nasal fossas (see Figs. 15, 16, and 17), have previously been described (see 

 page 43) > and it will readily be understood that this spongy partition between the orbital and 

 nasal cavities may easily disappear as the result of the pressure of tumors growing into the orbit 

 from the ethmoidal cells or from the nasal fossa. The openings leading to the ethmoidal cells 

 are to be found upon the outer wall of the nasal fossa. In Fig. 19 the middle turbinated has 

 been removed close to its attachment, so that the long slit-like infundibulum is exposed, pass- 

 ing from below upward and forward. In the anterior portion may be seen a probe which has 

 been introduced into the frontal sinus. The normal orifice of the maxillary sinus is situated 

 further posteriorly in the depth of the infundibulum. The entrance to the infundibulum is 

 also designated as the hiatus semilunaris. [This is incorrect to call the entrance to the 

 infundibulum the hiatus semilunaris. The hiatus semilunaris is a groove in the maxillary 

 side of the middle meatus and runs from the naso-frontal duct above downward and backward; 

 and since the anterior extremity of the middle meatus leads into the infundibulum, the hiatus 

 semilunaris is simply a recess from the middle meatus beginning at the naso-frontal duct. 

 The anterior ethmoidal cells, as well as the antral opening, open into the middle meatus 

 via the hiatus semilunaris. Overhanging the hiatus semilunaris is a large ethmoidal cell called 

 the bulla ethmoidalis. This cell or cells open into the middle meatus near the attached border 

 of the middle tubinated bone at about its middle. ED.] The ethmoidal cells usually bulge out 

 prominently above this hiatus, forming the bulla ethmoidalis, and above this is the orifice of the 

 anterior ethmoidal cells. The middle and posterior ethmoidal cells, on the contrary, open into 

 the superior meatus. Sometimes there is still a fourth turbinated bone at a higher level, in 

 which case the middle ethmoidal cells may open into the superior meatus and the posterior ones 

 between the third and fourth turbinated bones. 



In Fig. 19 a portion of the inferior turbinated bone has also been removed, exposing the 

 orifice of the nasal duct. During life it is accessible from the nostril, but it may be probed from 

 above to much better advantage. More worthy of note is the fact that access to the orifice of the 

 Eustachian tube may be gained through the naso-pharynx (see Fig. 19 and Plate 4). It lies 0.5 

 centimeter behind the posterior extremity of the inferior turbinated bone, and is bounded poste- 

 riorly by the torus tubarius (an enlargement produced by the underlying tube), which may be 

 easily located with a probe. The orifice of the Eustachian tube is six or seven centimeters from 

 the nostril; one centimeter behind the torus tubarius is the fossa of Rosenmuller (recessus infundi- 

 buliformis), which may catch the end of the probe when an attempt is made to pass this instrument 

 from the nostril into the tubal opening through the inferior meatus. 



A study of the illustrations of the outer wall of the nasal fossa (see Figs. 15 to 19, Plate 4) will 

 show that a chronic catarrh may extend into the Eustachian tube, into the frontal and maxillary 

 sinuses, and posteriorly into the pharynx. Tumors proceeding from the nasal fossa may grow 



