EXAMINATION OF THE ItESPlRATORY APPARATUS. 313 



Inspection sometimes reveals deformity of the external wall of the 

 smus. Such deformity, ho^vever, is rare, and Monssu has only 

 observed it m two cases of tuberculosis of the bones forming the 

 cranial wall. 



By percussion one detects abnormal sensibility,- and partial or com- 

 plete dulness over certain areas. 



Ma.viUarii .,,-»»s.-The maxillary sinus occupies the whole lateral 



Fig. 164. — General arrangement of the sinuses. The circular openings indicate 

 points at which trepanation is performed. 



region of the face, from the inferior extremity of the maxillary sj^ine 

 as far as the sub-orbito-palatine region. In front its external wall 

 is very solid, but behind, below the orbit, is extremely thin. Ex- 

 ternally the sinus is largely protected by the anterior insertion of the 

 external masseter muscle, a fact which explains how rarely it is 

 injured. 



Larynx. In consequence of its deep situation, the larynx can 



