Abnormal digastric muscle with unilateral quadrification of the anterior belly

Abstract

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.

Symmetrical anatomical variant of the anterior belly of the digastric muscle: clinical implicat

“…These anomalies involve mainly the anterior belly of the muscle and, in particular, the number of the anterior bellies or the presence of accessory bundles originating from a common tendon or from the intermediate tendon [3,11]. A quadrification of the anterior belly of the muscle was reported by Celik et al [3].…”

“…Digastric muscle variants have been described more frequently as unilateral [3,12,14] then bilateral [10,11,21] and symmetrical variants of the anterior bellies of the digastric muscle are more rare [1,11,21]. Aktekin et al [1] described 2 accessory anterior bellies, each derived from the homolateral intermediate tendon, crossed together the midline, drawing an "X", and reached the mandible laterally to the mental symphysis.…”

Duplicated anterior belly of the digastric muscle

“…Celik et al observed an abnormal digastric muscle with unilateral quadrification of the anterior belly, (4) while Sarikcioglu et al reported an anomalous digastric muscle with three accessory bellies and one fibrous band. (5) Both unilateral (6) and bilateral (7,8) variations have been reported.…”

Weave pattern of accessory heads to the anterior digastric muscle

“…There are many reports of variations of the digastric and stylohyoid muscles [1,2,[4][5][6][7][8][9]11]. In one study of 28 cadaver heads, unusual attachments of stylohyoid were observed in 22 sides (39.3 %), and atypical fibers from the digastric muscle were observed in 39 sides (69.6 %).…”