DISSECTION OF THE HEAD AND NECK. 



217 



anterior (ethmoidal) turbinated bone and the roof of the cavity (the 

 nasal bone) ; the middle meatus is another and larger interval between 

 the two turbinated bones; while the posterior meatus, the largest of these 





Fig. 24. 



Longitudinal Section op the Head, showing the Cavities of the Mouth, Nose, 

 AND Pharynx {Leyh), 



1. Frontal sinus ; 2. Lateral mass of ethmoid bone ; 3. Anterior meatus of nasal chamber ; 4. 

 Anterior turbinated bone ; 5. Middle meatus ; 6. Posterior turbinated bone ; 7, Posterior meatus ; 

 8. Circumvallate papillae of the tongue ; 9. Section of soft palate ; 10. Opening of right Eustachian 

 tube on side of pharynx ; 11. Isthmus of the fauces ; 12. Tipper aperture of the larynx ; 13. Com- 

 munication between pharynx and oesophagus ; 14. Thyroid body ; 15. Trachea. 



intervals, is included between the posterior (maxillary) turbinated bone 

 and the floor of the cavity. 



The Inner Wall (the septum nasi) is partly bony, and partly cartila- 

 ginous. In its upper part it is formed by the bony perpendicular plate 

 of the ethmoid, and at its posterior edge it is formed by the vomer bone ; 

 but for the greater part of its extent, the partition is composed of a plate 

 of cartilage — ^the septal cartilage. This septal cartilage is continuous 

 above with the perpendicular plate, which is merely an ossified portion 

 of it ; behind it is received into the cleft of the vomer, and expands on 

 the premaxillary suture ; in front it expands on the inner aspect of the 

 internasal suture ; and inferiorly the alar cartilages are movably con- 

 nected to it. 



