Median accessory digastric muscle: Radiological and surgical correlation

A median accessory digastric muscle was revealed during a dissection of the submental region. The muscle was located between the anterior bellies of t he digastrics, external to the mylohyoid and deep to the platysma. It appea red as a hat quadrilateral sheet. Its base arose from the front of the body of the hyoid bone near its upper border. Lower portion of the fibers, at t he right base of the muscle, initially traveled perpendicular to the lower fibers of the right mylohyoid. The rest of the muscle had a median course, with the cranial end inserting into the mandible between the digastric foss ae. The muscle elevated the hyoid bone and depressed the mandible when appr opriate stress was applied. No other morphologic abnormalities were found i n this region. Aberrant anterior bellies of the digastric muscles are uncom mon and occur bilaterally or unilaterally. This observation of a median acc essory digastric muscle has not previously been reported. Knowledge of this variant will help to avoid confusion with pathological conditions of the f loor of the mouth and the submental region. It is relevant both for the int erpretation of radiological images and during surgical procedures such as d issection of the anterior belly of the digastric for a malignant disease an d graft positioning. Clin. Anat. 14:42-46, 2001. (C) 2001 Wiley-Liss, Inc.