CHAPTER II 



HEAD AND NECK IN SECTION 



A LONGITUDINAL Sagittal section of the head is represented in Plate III. 

 The plate was executed from a fresh specimen. 



Assuming the head held with its long axis placed horizontally as in 

 the plate, the anterior extremity shows the upper and lower lips in 

 section and also the right middle incisor teeth in the upper and lower 

 jaws respectively, the upper one being carried by the right pre-maxillary 

 bone and the lower by the inferior maxillary bone. The inner surface 

 of the right pre-maxilla is shown and a section through the body of 

 the inferior maxilla. On the inner surface of the first-named hone 

 is an antero-posterior groove, which with a similar groove on the 

 corresponding bone of the opposite side forms the incisor foramen 

 when the two bones come into apposition. 



The anterior two-thirds of the section is divided into two parts by 

 the hard and soft palates. The portion above this line of division 

 represents the right nasal chamber, the boundaries of which are seen 

 to be as follows : Superiorly are the frontal and nasal bones, inferiorly 

 the palatine portion of the palatine bone, and the palatine plates of the 

 superior maxillary and pre-maxillary bones — these bones form what is 

 known as the " floor " of the chamber. 



Anteriorly the chamber communicates with the exterior by the 

 anterior nares, whilst posteriorly the right lateral mass of the ethmoid 

 bone is seen to project freely into its upper portion, and below this we 



