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™ just be separated from the test of the calcaneum at about the 
^Kteenth year, the growth of bone having been actively taking place 
for only six years. But every epiphyseal plane is a travelling plane, 
pnwiessing in a direction away from the centre to the end of the 
tone, and originally this plane must have occupied a position much 
further forward, possibly as far as the point x. , i 
Another view which occurs to me, but which I regard as less like y, 
IS that by the force of the bandages added to that of the Tendo 
Achillis the epiphysis, though forming new bone, cannot form it m 
an antero-posterior direction, and thus perform its true function of 
adding to the length of the bone. It is therefore compelled to 
deposit ossihc material in the direction of least resistance, name y. 
doivwards, and this downward prolongation is therefore somewhat 
of the nature of an exostosis. The upward pressure of the ground, 
corresponding to the weight of the child, must on this assumption 
offer less resistance than the bandages. 
In the X-ray photographs it will be noted that, according to the 
former view, the original posterior or epiphyseal en 
calcaneum is from y to and the patient walks on the insertion ® 
Tendo Achillis, a statement made in 1880, and based on a issec e 
speciraea . , c 
According to the latter explanation, the original posterior end ot 
the os calcis is from x to a, and the Tendo Achillis is still inserte 
about half an inch below tlie point x. 
The os calcis, then, is in any case responsible for the Posterior 
half of the arch. In contrast to this, the anterior half is produce y 
a small change in several bones, rather than by a great change in 
From the summit of the arch (the astragalus) forwards t^^re is a 
slight degree of shifting of the articular surfaces of eac on 
IS a purely anatomical change, and it is doubtful if any particular 
notice would be taken of these individual bones by any anatomist. 
The photographs are of value clinically in that they 
the naked eye at all events, the emphatic statement made ^ 
by Hilton that the fixation of a healthy joint, even for years, pro 
no pathological change. They are, further, of interes 
orthopaedic surgeon, in that they shew how muc can 
manipulation and continued pressure. 
