Bilateral anomaly of anterior bellies of digastric muscles.

During dissection of the submental region, the anterior bellies of the right and left digastric muscles were found to have two separate portions, inserting into different locations in the submental region. The lateral portions of the anterior bellies of the digastric muscles originated from the digastric fossa and inserted into the hyoid bone. The medial parts of the anterior bellies of the right and left digastric muscles ran medially and inserted into the mylohyoid raphe on both sides, forming accessory digastric muscles. This anatomic abnormality of the muscle could be significant in surgical procedures involving the submental region.