198 
A. LIAUTARD. 
The lateral walls are one internal, formed by one of the sides of 
the median lamella, flat and smooth; the other external, very anfrac¬ 
tuous, formed by the internal face of the great maxillary supporting the 
turbinated bones. 
'These turbinated are two in number, the supero-anterior or eth¬ 
moidal, and the infero-posterior or maxillary. Both are formed by a 
bony lamella, twisted upon itself in opposite direction, and in such a 
way that the longitudinal slit, which gives entrance in their interior, is 
situated in the middle meatus; they are wider at their superior extrem¬ 
ity ; and in all their extent slightly flatten from side to side. Both are 
divided in two parts by a transverse bony plate; the superior part com¬ 
municates with the sinuses, the inferior subdivided into several lodges 
open into the nasal cavities. Both at last are prolongated inferiorly by 
a fibro cartilage and mucous folds uniting them to the wings of the nos¬ 
trils. 
The bony frame of the ethmoidal turbinated bone is longer than 
that of the maxillary ; the contrary exists for the cartilaginous portion. 
This one has no connection of continuity with the ethmoid, while the 
former is, so to speak, the most anterior volute of that bone. The 
superior cavity of the ethmoidal communicates with the frontal sinus, 
that of the other with the inferior maxillary sinus. At last, the carti¬ 
laginous appendix of the maxillary turbinated bone is always divided 
m two portions, the anterior of which is directly in continuation with 
the internal wing of the nostrils; the cartilaginous portion of the eth¬ 
moidal turbinated, almost always single, disappears before reaching the 
nostrils. 
The turbinated bones are separated from each other, from the roof 
and floor of the nasal cavities, by very narrow spaces called meatus. 
The superior or anterior meatus is the narrowest; its anterior wall is 
formed by the roof of the cavity. The inferior or posterior meatus ex¬ 
tends from the maxillary turbinated to the nasal floor. The middle 
meatus, situated between the two turbinated, has towards its middle a 
slit, sometimes a foramen, opening into the maxillary sinuses; it is also 
m this meatus that open the anfractuous cavities of the turbinated 
bones. 
The ceiling, or roof, limits forwards the superior meatus ; it is hoi- 
lowed, curved gutter-like shape towards its superior extremity, which 
extends as far as the cribriform plate of the ethmoid, that is, far behind 
the posterior border of the guttural opening. The straight portion of 
its course has for base the nasal bone; the curved portion is excavated 
