THE ACCESSORY AIR-SPACES. 



1421 



so near the floor of the nose that the roomiest portion of the inferior meatus is 

 posterior. Therefore, the entrance of air into the lower part of the nasal fossa is 

 obstructed, and is favored toward the upper — "respiratory" — portion, especially- 

 through the wide anterior opening of the middle meatus, which reaches as high as 

 the tendo-oculi. This anatomical arrangement is the explanation of the fact already 

 mentioned, that odors on expired air are not recognized. 



The relations of the nasal chambers explain why a coryza may cause (a) lach- 

 rymation, by affecting the tear duct, lachrymal sac, and conjunctiva ; (d) dysphagia, 

 by extending to the pharynx by way of the posterior nares ; (r) hoarseness or cough, 

 by further extension to the respiratory tract ; (d) frontal headache, by involving the 

 frontal sinuses ; (e) "face ache," by implicating the antrum ; (/) grave intraorbital 

 or intracranial disease, by way of either the ethmoidal cells or the sphenoidal sinuses ; 

 basal meningitis by extending along the perineural or perivascular sheaths, or by 

 way of the lymphatics through the cribriform foramina to the floor of the anterior 

 cranial fossa ; (g) extension to the retropharyngeal lymph node (page 955), into 

 which certain of the nasal lymphatics empty, may result in a retropharyngeal ab- 

 scess ; or (k) infection (pyogenic or tuberculous) of the submaxillary, preauricular, 

 or deep cervical nodes may follow nose diseases. The graver of these complications 

 are, of course, associated with the severer infective forms of rhinitis. Malignant 

 growths — commonly sarcomatous — may begin in the nasal chambers and may extend 

 in any of the directions above mentioned. 



THE ACCESSORY AIR-SPACES. 



The nasal fossae communicate with a number of remarkable cavities, hollowed 

 out within the surrounding bones, which are filled with air and lined by mucous 

 membrane directly continuous with that of the meatuses. These pneumatic spaces 

 include the maxillary, the froyital, the sphenoidal and the palatal sinuses and the 



Fig. I I S3. 



Lower lateral cartilage 



Roof of inferior meatus 



Right maxillary sinus 



Inferior 

 turbinate 



Coronoid 

 process 



Temporal 

 muscle 



Masseter muscle 



Internal 



pterygoid 



muscle 



Eustachian 



tube 



Internal carotid artery 



of inferior meatus 



ferior turbinate 



Roof of 

 iiaso-pharynx 



Temporal muscle 

 Masseter muscle 



Internal 

 pterygoid muscle 



Eustachian tube 



Condyle of 

 mandible 



d muscle 



Pharyngeal tonsil 



Fosa of Rosenmijller 



Portion of transverse section of head passing through nasal fossae just below middle turbinates; the inferior surface 

 of the section has been drawn and the nasal fossae and other spaces are viewed from below. 



ethmoidal air-cells, all paired and within the corresponding bones. Since the 

 mucous membrane is thin and intimately adherent to the bones, the form of the cavi- 

 ties as observed in the recent condition corresponds closely to that seen in the 

 macerated skull. The size and extent of the spaces vary not only at different periods 



