THE FACE 



385 



begins in front at the lower part of the ascending plate of the maxil- 

 lary and passes downward and backward on the outer part of the 

 upper surface of the palatine 

 plate of that bone. 



The maxillo-turbinal 



FIG. 306. 



is 



k -Ethmoidal cleft 

 -Cleft plate of M 



Vomer-" 



TRANSVERSE SECTION OF HALF OF FACE. 

 Showing position of maxillo-turbinal bone. 



seventeen or eighteen milli- 

 metres long and five or six 

 millimetres thick. In shape 

 it is not unlike a pair of the 

 ethmoidal scrolls, in that it 

 consists of a longitudinal 

 plate, the maxillary process, 

 whereof the outer edge is 

 attached to the maxillary 

 and the inner edge splits 

 into two scrolls rolling up- 

 ward and downward. The 

 upward scroll is not much 

 more than a curved plate. 

 The partition slants from 

 without inward and down- 

 ward, and from in front backward and downward. The outer edge 

 is emarginate near the middle, to form the lower opening of the lach- 

 rymal canal. The superior scroll is a curved plate which fits between 

 the lower part of the ethmoidal scroll number 4'" on the outside and 

 number 4' on the inside. The inferior scroll forms the rest of the 

 bone and splits up into several secondary small divisions. The 

 maxillo-turbinal is covered with mucous membrane, and is attached by 

 fibrous tissue to the prenasal cartilages, which guard the entrance to 

 the anterior nares. A space left between this bone, the median inter- 

 nasal septum, the outer wall and the floor of the nasal cavity, is part 

 of the inferior meatus of the nasal chamber. The space between the 

 lower part of the lateral ethmoid and the maxillo-turbinal is the 

 middle nasal meatus. 



Nomenclature. The maxillo-turbinal is sometimes called the 

 inferior turbinated bone, os turbinatum, or os turbinale. The word is 

 derived from turbo, a whirl ; hence anything rolled into a scroll. 



Concha nasalis inferior, or concha inferior, from concha, a shell, has 



25 



