Abnormal digastric muscle with unilateral quadrification of the anterior belly.

During dissection of the submental region we observed that the anterior belly of the left digastric muscle had four separate insertions. These muscle bands united in a common tendon as they continued with the posterior belly. This is an anatomical variation in the mylohyoid digastric muscle group in the floor of the mouth. When an asymmetry in the floor of the mouth is detected during diagnostic procedures, such as radiologic studies, anomalies of the anterior belly of the digastric muscle should be considered besides other reasons of asymmetry. Additionally, possible occurrence of such anomalies should be remembered during surgical procedures involving the submental region. This unique variation has not been reported in the literature. Copyright 2002 Wiley-Liss, Inc.