164 Mr Manners- Smith, A Study of the Navicular 
Facies lateralis. Articulatio cubo navicularis. The cuboid 
facet is situated at the junction of the facies articularis anterior, 
and facies lateralis. It is present in 332 specimens or about 
70 per cent, of those examined with reference to this articu- 
lation. 
Articulatio calcaneo navicularis. This occasional facet for the 
os calcis is present in 13 specimens, 8 right and 5 left. The 
facet is close to the surface for caput tali, between the cuboidal 
facet and the plantar point. Its shape varies slightly, in two 
cases it was rhomboidal, in one triangular, in one oblong, in one 
wedge-shaped, in three cases there was a fairly sharp ridge 
separating it from the cuboidal facet. Phitzner found this articu- 
lation in 8 specimens. The presence of this articulation is due 
according to Phitzner to the existence of a rudimentary calcaneus 
secundarius which has fused with the os calcis. 
Tuberositas ossis navicularis. 
This may be considered, from a descriptive point of view, 
under size, prominence and shape, and from a morphological, 
embracing the embryology of the tuberosity, its components and 
their nature. 
Description: In the following account I have included as 
tuberosity that portion of the whole navicular which projects 
mesially and plantanvards, beyond a line drawn round the bone 
from the tibio plantar angle (apex of pear-shaped facet for caput 
tali) to the apex of the facet for the internal cuneiform. 
The apex of the tuberosity may occupy three situations : 
(a) It may be situated at a small tubercle close to and dorsal 
of the tibio plantar angle (apex of pear-shaped astragalar facet). 
This may be called the apophysial apex. 
(b) It may be situated a line or two distal ly and plantar- 
wards of the above tubercle. This may be called the epiphysial 
apex. 
(c) It may be produced proximally, so as to occupy a position 
£ to \ of an inch posterior to the above tubercle. This may be 
called the sesamoid apex. 
Morphology. The portion of bone included in the above de- 
scription as tuberosity will be found to consist of a variable 
number of elements of different morphological value. The 
evidence derived from those abnormal cases in which a separate 
ossicle is formed in this situation would suggest that the whole 
tuberosity is made up of one, two, or in some cases, three com- 
ponents. 
(a) A portion near the corpus which is merely an apophysis 
of that body, from this the whole of the facies anterior and facies 
dorsalis and facies articularis are formed, together with a little 
