DE. J. CLELAND ON THE VAEIATIONS OF THE HUMAN SKULL. 
153 
true measure of prognathism, lie recommends for that purpose Lucae’s system of 
ordinates. 
Both Virchow’s and Welcker’s nasal angles are objectionable, because the upper of 
the containing lines is a mere compromise between the directions of two portions of the 
base which lie at a very variable angle one to the other ; while Lucae’s method fails by 
being dependent on a line which is neither horizontal, as he and Welcker suppose, nor 
o-ives any indication of the position of any part of the base ; and the same objection 
holds good against setting the skull, for the determination of its prognathism according 
to Mr. Busk’s method, in such a manner that a line from the ear to the fronto-nasal 
suture shall be vertical. 
Virchow has been misled by his method. The skull of the Cretin 53 years old and 
that of the new-born Cretin figured in his work, do not get their peculiar characters of 
base, as shown in his plates, accounted for by the theory of “ kyphosis” or increased 
curvature. The basilar process in both those skulls certainly lies at a less obtuse angle 
with the body of the postsphenoid, to which it is synostotically joined, than it does in 
the respective healthy skulls with which he compares them ; but that circumstance is 
nearly made up for in the Cretin child, and in the adult Cretin is more than made up 
for, by the longitudinal axis of the sphenoid lying almost in a line with the cribriform 
plate of the ethmoid, instead of making the angle with it which is usual ; so that a line 
from the fronto-nasal suture laid on the floor of the anterior cranial fossa and continued 
backwards, in the young Cretin touches, and in the old Cretin cuts the dorsum selke, 
while in the healthy skulls with which they are compared it lies far above that process. 
This altered relation of the sphenoid to the ethmoid accounts for Virchow finding 
the “ nasal angle” in the Cretins larger than in healthy skulls*. Had he taken the floor 
of the anterior cranial fossa as the upper of the two lines containing the nasal angle, he 
would have found that the angle was smaller in the Cretin skulls than in the healthy, 
and that however prognathous the appearance which the Cretin skulls may have pre- 
sented during life, that appearance was not to be accounted for by projection of the face 
from under the floor of the cranium, but in some other way. 
Welcker’s statement that the greater the curvature of the base as estimated by means 
of the angula sellee (Sattelwinkel) the smaller the nasal angle as he measures it, is 
undoubtedly true, but is uninstructive ; for it is self-evident that the more the basilar 
process is bent down from the direction of the floor of the anterior cranial fossa the 
more will the upper of the two containing lines of Welcker’s nasal angle be depressed, 
and that if in any skull the inclination of the basilar process were changed while the 
face was left untouched, the alteration in the angula selke and the nasal angle would 
only be different expressions of the one anatomical change. Seeing, then, that this nasal 
* This combination of what may he termed curving downwards of the presphenoid with curving upwards of 
the ethmoid is often met with in skulls of low type (see p. 169). It has occurred in the Australian skull figured 
by Landzert ; and had that writer caused the upper limb of his angula sellse to pass from the upper surface of 
the presphenoid forwards to the fronto-ethmoidal or fronto-nasal suture, instead of following the plane of the 
presphenoidal surface, his conclusions must have been materially modified. 
