Simple inflammation of ligaments is of occasional occurrence but, unless
considerable injury is done this tissue, no perceptible manifestation of
injury results. No doubt many cases wherein fibrillary fracture of
ligaments (sprain) takes place some lameness is caused, but because of
the dense, comparatively nonvascular nature of these structures, little
if any manifestation, except lameness, is evident. And such cases, if
recognized are usually diagnosed by excluding the existence of other
possible causes and conditions which might also cause lameness.

Certain ligaments are subjected to strain more than are others and
therefore, when so involved, frequently cause lameness. Examples of this
kind are affections of the collateral (lateral) ligaments of the
phalanges. Because of the leverage afforded by the transverse diameter
of the foot, when an animal is made to travel over uneven road surfaces,
considerable strain is brought to bear on the collateral ligaments of
the phalanges. A sequel to this form of injury is a circumscribed
periostitis at the site of attachment of the ligaments and frequently
the formation of an exostosis--ringbone--results.

Where sudden and violent strain is placed upon a ligament and rupture
occurs, the division is usually effected by the ligament being torn from
its attachment to the bone. In such cases, a portion of periosteum and
bone is usually detached and the condition may then properly be called
one of fracture. In some cases of this kind recovery is tardy, because
of the difficulty in maintaining perfect apposition of the divided
structures, and reactionary inflammation is not of sufficient extent to
enhance prompt repair. In fact, some cases of this kind seem to progress
more favorably, when no attempt at immobilization of the affected member
is attempted.