THE CAVITY OF THE NOSE. 667 



three are molar teeth. For details as to the form and structure of 

 the teeth reference must be made to a work on systematic or general 

 anatomy. 



SECTION XII. 



DISSECTION OF THE NOSE. 



The skull will now be divided from before backwards into two Directions, 

 halves for the examination of the nasal cavity and of various remain- 

 ing parts of the anatomy of the skull. The tongue and larynx will 

 be separated, as directed, and put aside for examination by the 

 workers on the two sides together ; after which they will similarly 

 examine the pre vertebral region and the ligaments. In this Section 

 also, and in the next, the students work together. While examining 

 the boundaries of the nose, the student should be provided with 

 a similar section of a macerated skull. It is also desirable, in order 

 to fully comprehend the form of the cavity, that he should have the 

 opportunity of inspecting a coronal section of the nose in the recent 

 state. 



Dissection. Before sawing the bone, the loose part of the lower Dissection, 

 jaw should be taken away, and the tongue, hyoid bone, and larynx, 

 all united, are to be detached from the opposite half of the lower 

 jaw, and laid aside till the dissectors are ready to use them. 



On the riijht side of the middle line saw carefully through the frontal Cut through 

 and nasal bones, the cribriform plate of the ethmoid, and the body 

 of the sphenoid bone, without letting the saw descend more than can 

 be helped into the nasal cavity. 



Xext the roof of the mouth is to be turned upwards, and the soft Cut soft 

 parts are to be divided on the right side opposite the cut in the roof Uwbone in 

 of the nose. Then by sawing through the hard palate and the roof of 



. J mouth. 



alveolar process ot the upper jaw along the same line, the piece of 

 the skull will be separated into two parts, right and left ; the right 

 half will serve for the examination of the meatuses, and the left 

 will show the septum nasi, after the mucous membrane has been 

 removed. 



The CAVITY OF THE NOSE is placed in the centre of the bones of situation of 

 the face, being situate above the mouth, below the cranium, and nose ' 

 between the orbits. The space is divided into two nasal fossae by Division 



, . i .... ,, into two. 



a vertical partition, the septum. 



Each fossa is elongated from before backwards, and compressed from Form and 

 side to side. Its length is greater below than above, and measures 

 near the floor about three inches. Its height in the middle of the 

 cavity is about one inch and three-quarters, becoming less in front 

 and behind. The upper part of the fossa is narrow (tig. 235, p. 668), 

 not exceeding one-eighth of an inch in breadth, and has been named 

 the olfactory deft, which extends down as far as the lower border of 



