Aim: Anterior belly of digastric muscle forms the boundary of submental and submandibular triangles, and is an important surgical landmark of the suprahyoid region. It attaches above to the digastric fossa on the mandible and below to the intermediate tendon of the muscle.
Materials and methods: Thirty formalin-embalmed cadavers were examined for variations in the anterior belly of digastric muscle.
Results: Anomalous muscles were seen in two cases (6.6%), one unilateral and one bilateral. Anterior belly of digastric muscle was absent on the left side in one cadaver. Symmetrical appearance of accessory muscles, medial and parallel to the main bellies was noted in the bilateral case.
Conclusion: Variations in the anterior belly like the presence of accessory fibers or absence of the anterior belly alter the anatomic layout of the region between the mandible and hyoid bone, which is relevant for clinicians, surgeons, and radiologists dealing with the suprahyoid area.
Clinical significance: Atypical anterior belly of digastric muscle is likely to affect the movements of joints involving mandible and hyoid, surgical interventions in the suprahyoid region, and the interpretation of diagnostic scans.
Watkinson JC, Gleeson M. Neck. In: Standring S, editor. Gray's anatomy: The anatomical basis of clinical practice. 41st edition. Elsevier;2016: 449.
Zdilla MJ, Soloninka HJ, Lambert HW. Unilateral duplication of the anterior digastric muscle belly: a case report with inplications for surgeries of the submental region. J Surgcase Rep. 2014;12:1-2.
Loukas M, Louis RG, Kapos T, Kwiatkowska M. A case of bilateral accessory digastric muscle. Folia Morphol. 2005 May;64(5):233-236.
Bakrici S, Kafa IM, Uysal M, Sendemir E. Anterior belly anomalies of the digastric muscle: case report. Eur J Anat. 2007;11(3):201-203.
Uzun A, Aluclu A, Kavakli. Bilateral accessory anterior bellies of the digastric muscle and review of literature. AurisNasus Larynx. 2001;28:181-183.
Mascaro MB, Picoli LC, Santos FM, Bonsi AB, Souza MR, Prosdocimi FC. Anatomical variation of the anterior belly of the digastric muscle: case report and clinical implications. J Morpho Sci. 2011; 28: 72-75.
Atkekin M, Kurtoglu Z, Ozturk AH. A bilateral and symmetrical variation of the anterior belly of the digastric muscle. Acta Med Okayama. 2003;57:205-207.
De-Ary-Pires B, Ary-Pires R, Pires-Neto MA. The human digastric muscle: Patterns and variations with clinical and surgical correlations. Ann Anat. 2003;185:471-479.
Seok H, Park YT, Kim SG, Park YW. Correction of posttraumatic anterior open bite by injection of botulinum toxin type A into the anterior belly of the digastric muscle: case report. J Korean Assoc Oral Maxillofac Surg. 2013;39:188-192.
Zdilla MJ. Screening for variations in anterior digastric musculature prior to correction of post-traumatic anterior open bite by injection of botulinum toxin type A: a technical note. J Korean Assoc Oral Maxillofac Surg. 2015;41:165-167.
Tan ST. Anterior belly of digastric muscle transfer: a useful technique in head and neck surgery. Head and Neck: Journal for the Sciences and Specialties of the Head and Neck. 2002;24(10):947-954.
Bergman RA, Afifi AK, Miyauchi R. Illustrated encyclopedia of human anatomic variation: opus I: muscular system: alphabetical listing of muscles. Psoas Minor. Viewed from http://www. anatomyatlases. org/AnatomicVariants/MuscularSystem/ Text/P/Psoas. shtml (accessed in July, 2014). 2015.
Mangalagiri A, Razvi MRA. Variations in the anterior belly of digastric. Int J health Sci. 2009;3:257-262.
Fujimura A, Onodera M, Feng XY, Osawa T, Nara E, Nagato S,et asl Abnormal anterior belly of the digastric muscle: a proposal for the classification of abnormalities. Anatomical science international. 2003;78(3):185-188.
Sargon MF, Onderoglu S, Surucu HS, Bayramoglu A, Demiryurek D, Ozturk H. Anatomic study of complex anomalies of the digastric muscle and review of literature. Okajimas Folia AnatJpn. 1999;75:305-314.
Holibkova A, Machalek L. A report on anomalies of digastric muscle. ActaUnivPalackiOlomucFac Med. 1999;142.