I4I2 



HUMAN ANATOMY. 



When the infundibulum does not end bhndly above, which it often does (page 

 194), its upper extremity, usually somewhat expanded, receives the opening of the 

 frontal sinus, osthivi frojitale. The sinus is, however, not dependent upon the 

 infundibulum for its communication with the middle meatus, since, as pointed out 

 by Zuckerkandl, between the front of the attachment of the middle turbinate bone 

 and the uncinate process of the ethmoid there exists a passage which leads to the 

 ostium frontale. Into the upper part of the infundibulum usually open some of the 

 anterior ethmoidal air-cells ; lower in the groove lies the oval or slit-like osthan 

 viaxillare, the chief communication of the antrum of Highmore. When the latter 

 is provided with an additional orifice, as it is in 10 per cent. (Kallius), the smaller 

 accessory communication opens into the infundibulum a few millimeters behind 

 the principal aperture. Above the hiatus semilunaris, either on or above the 

 bulla, is usually seen the slit-like opening through which the middle ethmoidal cells 

 communicate with the meatus. 



The Inferior Meatus. — This passage (meatus nasi inferior), the largest of the 

 three, measures from 4.5-5.5 cm. in length, its anterior end lying from 2.5-3.5 cm. 

 behind the tip of the nose. At first relatively contracted, it abruptly expands, not 



Fig. I I 76. 



Scalp 



Cerebral hemisphen 



Superior longitudinal sinus 

 Bone 



Falx cerebri 



Ethmoidal cells 



Lower end of probe 



lying in hiatus 



semilunaris 



Middle turbinate 



Probe passing from 



antrum into, 



infundibulum 



Inferior turbinate 



Nasal septum 



Right eyeball 



Hiatus semilunaris 

 Middle meatus 



—Maxillary sinus 



Inferior meatus 

 Floor of nasal fossa 



Oral mucous membrane 



1 oiigue 



Frontal section of head, viewed from behind, showing nasal fossae and communications 

 with frontal and maxillary sinuses. 



only in height, in correspondence with the arched attached border of the lower 

 turbinate, but also in width. Farther backward, it gradually diminishes and is again 

 reduced at its choanal end. On the lateral wall of the inferior meatus, usually from 

 3-3.5 cm. behind the posterior margin of the nostril, after removal of the lower 

 turbinate, may be seen the opening of the naso-lachrymal duct. The position and 

 form of the orifice are subject to much variation. When close to the arching attached 

 border of the concha, the aperture is usually oval or even round ; when its position 

 is lower, it is narrow and slit-like, obliquely vertical, and often guarded by a fold of 

 mucous membrane, the so-called valve of Hasner. 



The arched roof of the nasal fossa is divisible into a naso-frontal, an 

 ethmoidal and a sphenoidal part in accordance with the bones over which the 



