560 
REVIEW—DISEASES OF THE FOOT 
performances. The parts seem to him altogether inadequate to per¬ 
form their tasks: but if, to gratify his curiosity, he turns his at¬ 
tention more minutely to the construction of these parts, he will 
find, on the one hand, the greatest possible strength condensed in 
the smallest compass, and, on the other, a machine furnished with 
an immense variety of springs most admirably constructed and 
ingeniously arranged. 
‘‘The curious inquirer is disposed to ask, as he proceeds to ex¬ 
amine this structure and to compare it with man and other animals, 
How is it that there are no muscles or flesh below the knee, 
when he finds so many in the human hand or foot, as well as in 
the legs of the feline and canine races] We must reply to this ' 
natural question, that, from the length of the leg of a horse, and the 
distance from the body to the ground, if the muscles had been 
placed below the knee, the weight of these parts would have been 
so great as to have obstructed very considerably the animal’s 
movements, on the same principle that a pound weight at the end 
of the long arm of a steel-yard would balance many pounds on the 
short arm. In like manner, the muscles, in which, of course, the 
moving power resides, are disposed above the knee, and effect 
their purpose through the medium of the tendons or sinews, which 
act as so many ropes in readily communicating motion to the foot. 
On the same principle we find, in the construction of the bones 
of the leg, the greatest condensation of strength, from their being 
arranged in the forms of cylinders, that being the strongest form; 
and where there is the greatest danger of fractures occurring (the 
middle of the bones), there we find most weight and solidity: 
but towards their extremities a greater size is afforded for the articu¬ 
lation of joints and the attachment of muscles. With this increased 
size, however, we have a diminished weight and solidity of struc¬ 
ture. This allusion to the bones of the leg naturally brings us to 
consider, in the first place, the uses of those parts nearest the knee. 
The large metacarpal or cannon bone receives the greater portion 
of the animal’s weight, and transmits it to the bones below. The 
two smaller metacarpal bones receive some portion of the weight, 
and from their elastic connexion with the shank bone are supposed 
to act as springs in diminishing concussion. 
“Let us inquire as to their capability of sustaining weight and 
diminishing concussion. We find that the inner splint bones arti¬ 
culate with a small bone of the knee—the trapezoid; but the unci¬ 
form, being longer than the pisiform, presses partly on the outer 
splint bone, and partly on the cannon; while the articulating surfaces 
of both bones are somewhat higher than that of the cannon, which 
exposes them still more to pressure. We take it, that even the 
circumstance of the flat articulating surface of the cannon bone 
