Vol. 33, Nš 4

Bilateral variation of anterior belly of digastric muscle

Azeredo, R. A.; Cesconetto, L. A.; Torres, L. H. S.

KEYWORDS: anatomy, anatomic variation, digastric muscle

ABSTRACT: Introduction: Digastric is a suprahyoid muscle and usually consists of two bellies. Its action consists in drawing the mental region downwards and backwards when opening the mouth, resulting in the depression of the mandible. Methods and Results: During a routine dissection of the cervical region, a muscle bundle arising from the intermediary tendon going towards the middle line was found. The supranumerary belly arised from the intermediary tendon so that some bundles inserted on the middle rafe and others continued towards the mento and inserted on the belly of mylohyoid muscle at the same side. These anatomic variations on the anterior belly of the digastric muscle could be significant during surgical procedures involving the submental region. Conclusion: Besides this surgical importance, we suggest that these supranumerary bellies have no direct action on the mandible, but on the floor of the mouth, due to its insertions on the mylohyoid muscle.