In the case reported, an interesting variation of the left digastric muscle of an adult female cadaver was found during routine anatomical dissection of the anterior neck region. Additionally to the usual anterior and posterior bellies, there was a well-developed aberrant muscular slip starting from the digastric anterior belly and inserting to the inner surface of the mandibular angle in a manner nearly parallel to the posterior belly. This additional slip, together with the anterior belly and mandibular base enclosed a small but false submandibular triangle. The submandibular gland was displaced slightly posteriorly with the submandibular duct passing between the aberrant slip and the usual posterior belly.The reported muscle variation may have importance in open surgical procedures in the neck region. Our case report provides an additional understanding of digastric muscle variations and their clinical significance.