A unique symmetrical variation of the median accessory anterior digastric muscle.

A median accessory anterior digastric muscle was identified during a routine dissection of the submental triangle in an embalmed 86-year-old Caucasian female cadaver. The muscle had a digastric and a mylohyoid variant. The digastric variant was triquetral, symmetrical, with a mandibular apex attachment at the symphysis between the digastric fossae and two base attachments at the right and left intermediate tendons, approximately 3 mm apart. A midline raphe connected the base fibers, extending cranially toward the apex. The mylohyoid variant presented as two thin muscle strands originating from the cranial mylohyoid near the raphe, and inserting into the intermediate tendons, parallel to the mylohyoid nerve's path. No enlarged lymph nodes were noted. This accessory muscle, a potential landmark in neck surgeries, may be mistaken for the digastric, risking incomplete tissue resection. This report describes its anatomy to guide surgeons in neck dissections.