artery is injured during the procedure. Thus the contents of the mandibular canal — blood vessels and nerve — should be care-fully attended during surgical procedures.

In the bicuspid region, the inferior alveolar artery bifurcates, sending the larger branch through the mental foramen into the chin as the mental artery. This artery provides oxygenated blood for the soft tissues of the chin, and anastamoses with branches of the inferior labial artery. Within bone, the smaller branch continues anteriorly toward the midline as the incisive artery. This artery produces numerous smaller branches which supply the incisors and pass out of the bone into the soft tissues through the incisive foramina. These incisive foramina are usually very distinct on dried specimens of the mandible.

Injury to the smaller twigs supplying the residual crest is usually uneventful. Blood quickly clots within the small severed artery, stopping the hemorrhage, and healing proceeds without undue delay. The exception to this might be in the patient with clotting difficulties, a tendency toward which the patient is probably aware and can reveal in a competent medical history prior to an implantation procedure.

Due to poor blood supply, healing may be slow in the mandible. The monitoring effects of blood on healing are less responsive in a poorly vascularized area than in a richly supplied one. Thus surgical procedures should avoid excessive trauma, and be rapid and efficient. Delays in closing the site should be avoided, and sutures should closely reapproximate the tissues.

Before the lingual artery turns into the body of the tongue, it divides into two major branches: the deep lingual artery (10) and the sublingual artery (11) . The deep lingual artery, the major continuation of the parent artery, runs upward into the body of the tongue (12) and passes forward in a tortuous course to the tip of the tongue, where 'one of its terminal branches anastamoses with its bilateral counterpart to form the acus raninus. In the more anterior portion of the tongue, the deep lingual artery lies very close to the inferior surface of the tongue. Its course through the tongue is characterized by numerous curves that flatten as the tongue elongates and changes position.

In the base of the tongue, the deep lingual artery gives off one or more branches that arise almost vertically to supply the dorsum of the tongue. These are the dorsal lingual arteries.

The sublingual artery courses along the floor of the mouth medial to the sublingual gland (13), which it supplies. More im-

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