IN THE HUMAN FRAME. 
67 
into the bottom of the cup; which ligament keeps the 
two parts of the joint so firmly in their place, that none of 
the motions which the limb naturally performs, none of the 
jerks and twists to which it is ordinarily liable, nothing 
less indeed than the utmost and the most unnatural vio¬ 
lence, can pull them asunder. [PI. XI. fig. 1.] It is 
hardly imaginable, how great a force is necessary, even 
to stretch, still more to break, this ligament; yet so flexible 
is it, as to oppose no impediment to the suppleness of the 
joint.* By its situation also, it is inaccessible to injury 
from sharp edges. As it cannot be ruptured, (such is its 
strength,) so it cannot be cut, except by an accident which 
would sever the limb. If I had been permitted to frame a 
proof of contrivance, such as might satisfy the most dis¬ 
trustful inquirer, I know not whether I could have chosen 
an example of mechanism more unequivocal, or more free 
from objection, than this ligament. Nothing can be more 
mechanical; nothing, however subservient to the safety, 
less capable of being generated by the action of the joint. 
I would particularly solicit the reader’s attention to this 
provision, as it is found in the head of the thigh-bone ; to 
its strength, its structure, and its use. It is an instance 
upon which I lay my hand. One single fact, weighed by 
a mind in earnest, leaves oftentimes the deepest impres¬ 
sion. For the purpose of addressing different understand¬ 
ings and different apprehensions—for the purpose of senti¬ 
ment, for the purpose of exciting admiration of the Crea¬ 
tor’s works, we diversify our views, we multiply examples; 
but for the purpose of strict argument, one clear instance 
is sufficient; and not only sufficient, but capable, perhaps, 
of generating a firmer assurance than what can arise from 
a divided attention. 
The ginglymus , or hinge-joint, does not, it is manifest, 
admit of a ligament of the same kind with that of the ball 
and socket joint, but it is always fortified by the species of 
ligament of which it does admit. The strong, firm, invest¬ 
ing membrane, above described, accompanies it in every 
part; and in particular joints, this membrane, which is 
properly a ligament, is considerably stronger on the sides 
than either before or behind, in order that the convexities 
may play true in their concavities, and not be subject to 
slip sideways, which is the chief danger; for the muscular 
* This ligament is also common to all quadrupeds, even in the more 
large and unwieldy, as the Hippopotamus and Rhinoceros—it is wanting 
in the elephant only, whose limbs, ill qualified for active movements, do 
not seem to require this security to the joint.— Paxton. 
