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A fissure or perpendicular division of one or both lips. It has been so called, in consequence of the upper lip of the hare being thus divided. Hare-lip is generally congenital; at other times it is accidental, or produced by a wound, the edges of which have not been brought into contact, and have healed separately. It is simple, when there is but one division; double, when there are two; and complicated, when there is, at the same time, a division or cleft of the superior maxillary bone and of the palate-Cleft or fissured palate, Wolf's jaw, Palatum fissum, Rictus lupinus; or a projection of the teeth into the separation of the lip. In the Hare-lip operation, there are two indications to be fulfilled. First, to pare, with the knife or scissors, the edges of the cleft, and, afterwards, to preserve them in contact; in order to cause adhesion. This last object is accomplished by means of pins, passed through the edges of the division; in other words, by the twisted suture. The projecting teeth must, of course, be previously removed. If there be separation of the palate, it will become less and less after the union of the lip, or the operation of staphyloraphy may be performed upon it.

A failure in continuity of the upper lip giving it the split appearance of a hare or rabbit.

n. A lip, more commonly the upper one, having a fissure or perpendicular division like like that of a hare.