294 
DE. CLELAJfD ON THE EELATIONS 
The alterations which take place with growth in the form of the vomer are results of 
the peculiar conformation of the human face, which is developed with a view to speech 
and expression, and not, as in the lower animals, for the mere prehension of food. The 
more the maxilla projects the wider is the gape allowed; but in Man, especially in the 
civilized races, instead of there being any such projection, the palate is short and the 
incisors perpendicular; and, as adult life approaches, the nasal fossse and antra of 
Highmoee are enlarged to such an extent by downward growth of the maxillae as to 
render the perpendicular height of the posterior nares quite a distinctive characteristic 
of the human skull. In consequence of this elongation of the face, the distance between 
the cribriform plate and the palate is rapidly increased. This distance the central plate 
of the ethmoid and the vomer must span ; and as they stretch to accomplish this object, 
they become attenuated and most frequently lose their symmetry. Often indeed the 
first degeneration from its typical form which the vomer undergoes is a deviation of its 
laminee from the middle line. This is found even in children. 
As the central plate of the ethmoid grows downwards, its edge, which is advancing at 
the expense of the septal cartilage, corresponds with that structure in thickness. But 
only the edge is so thick ; the rest of the plate gets thinner and thinner as it becomes 
elongated, and may even present irregular perforations. The vomer, on the other hand, 
embraces the cartilage from below. But when the central plate of the ethmoid, growing 
down from above, comes in contact with the alee as they stretch upwards in the peri- 
chondrium, the ossifications from above and below unite, and if the middle line has 
been perfectly preserved, the cartilage between them is surrounded above, below, and 
on each side by bone. Very rarely this vestige of cartilage disappears entirely, and 
there is then a thin lamina of bone extending from the cribriform plate to the palate, 
and in it a diagonal of stronger bone stretching from the crista incisiva to the sphenoid. 
Generally, however, the deviation from the middle line is considerable, and the central 
plate of the ethmoid, though anchylosed with both alse at the back part, is in front 
united more with one lamina than the other (usually most with that on the concave 
side of the septum), while the other tends to undergo atrophy. The cartilage between 
them is thus left more exposed on one side than the other, or sometimes is exposed on 
one side at one part, and on the other side further back. Occasionally, even in old sub- 
jects, a thread of cartilage can be traced back into one of the sphenoidal sinuses. 
When the vomer is described as only grooved at its upper and back part, and exhi- 
biting a cul-de-sac for the reception of the rostrum, the description is that of an irre- 
gular piece of bone consisting of the vomer and part of the ethmoid. The specimens 
chosen for study by the describers have been taken from skulls in which the vomer has 
already become thoroughly united to the central plate ; and when it has been sought to 
separate it, the central plate has given way at its weakest part. In other instances the 
fracture is efiected through the alee of the vomer. It is utterly impossible to separate 
a vomer accurately from the central plate after the two bones have come into contact. 
The ridge which one so frequently meets with on one side of the vomer in specimens 
