I4i8 HUMAN ANATOMY. 



apparent when, as during an acute coryza, the fossa; are more or less completely 

 obstructed and the voice becomes flat and entirely without resonance. 



{b) The relations between the nasal chambers and the sexual apparatus are of 

 practical importance and have as an anatomical basis the analogy between the mucosa 

 covering much of the turbinates and part of the septum, and the erectile tissue of the 

 penis, and the sympathy between the erectile portions of the generative tract and 

 erectile structures — c. g. , the nipple — in other parts of the body. 



2. {a) The distinction between the nasal chamber and the vestibule is, in the 

 main, based upon the difference in their lining membrane, that of the vestibule 

 being simply a continuation inward of the external integument to the line {limen 

 nasi) at which the nasal fossa proper begins. The x'estibular ca\-ity is provided with 

 rigid hairs (to aid in arresting foreign particles carried in with the air current), and 

 sebaceous glands, and is especially susceptible to eczematous or furuncular affections. 

 Diseases of the vestibule may, therefore, be dealt with as though they Avere affections 

 of the skin ; while diseases of the mucosa of the nasal chambers are to be treated on 

 the same principles as those of the mucous membranes generally, with special refer- 

 ence to its erectile character and to its close relation to the underlying periosteum 

 and bone. 



{b^ The sutural lines of the premaxilla, of the maxilla, and of the palatal bones 

 aid in determining the boundaries of the subdi\'isions of the nasal chamber, which 

 are indicated to some degree by the production of the planes of the sutures of the 

 roof of the mouth, vertically upward through the nasal chambers. 



{c) The morphological significance of the septum, placed as it is in the median 

 line of the face of the embryo, with the turbinate bones lodged to its right and left 

 sides, remains the same in the skull of the adult, notwithstanding the fact that, with 

 culti\'ated races at least, the septum is usually deflected through the greater part of 

 its course from the median line. This deflection has been said to be due to the 

 persistent growth of the septal bones in a \'ertical plane after their edges have 

 united — the apex of the deflection being often found at the junction of the ethmoid 

 and vomer ; any preponderance in strength of one of these bones will cause bending 

 of the weaker — usually the perpendicular plate of the ethmoid. The usual direction 

 of the deflection is to the left, and this has been thought to be due to the habit of 

 using the right hand in blowing the nose. Asymmetry of the nasal chambers is a 

 result of the deflection. One of these chambers, commonly the left, is much smaller 

 than its fellow of the opposite side, and may be occluded, when the right chamber 

 will be larger than normal and possess both osseous and erectile structures which 

 have undergone physiological hypertrophy. Care should be taken to distinguish 

 between such hypertrophy and the effects of diseased action (Allen). 



The anterior nares are directed downward and are on a lower plane than the 

 floor of the nose. To examine the interior of the nose the movable nostril must 

 therefore be elevated and the head thrown backward. The speculum shaped for the 

 purpose should not be passed beyond the dilatable cartilaginous portion. With good 

 light one may see the anterior part of the middle turbinate bone, a larger portion of 

 the inferior turbinate, the beginning of the middle meatus, and get a freer \-iew of the 

 inferior meatus, the septum and the floor of the nose. The lower orifice of the nasal 

 duct cannot be seen, although it is only about an inch from the orifice of the nostril, 

 and three-fourths of an inch above the floor of the nose. This is due to the fact 

 that it is concealed behind the attached and depressed anterior end of the inferior 

 turbinate. 



To expose better the structures in the external wall of the narrow and rigid 

 nasal fossa, various procedures ha\'e been adopted. Rouge made an opening into 

 the anterior nares from the mouth, by incising in the angle between the upper lip and 

 the gum. By separating the alar cartilages from the bones and dividing the cartilag- 

 inous septum the movable anterior portion of the nose can be turned upward, giving 

 a full exposure of the nasal fossae, without leax-ing an unsightly scar. 



To permit a freer exploration with the finger, Kocher divided the septum as far 

 back as possible with scissors. He also divided the roof of the nose near the septum, 

 turning the divided parts aside. An osteoplastic flap may be made by extending this 

 incision upward, dividing the bone in this line and making a second incision around 



