Asymmetry of the Accessory Anterior Digastric Muscle Bellies: The Clinical Significance in Facial and Neck Surgery

Maria Piagkou,Nikolaos Lazaridis,Nikolaos Anastasopoulos,Konstantinos Natsis

doi:10.7759/cureus.7148

Maria Piagkou, Nikolaos Lazaridis + Show 2 more

Open Access

https://doi.org/10.7759/cureus.7148

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Abstract

The anterior digastric muscle belly (ADMB) may present significant variations of substantial surgical importance. We present an unusual complex bilateral asymmetry of an accessory ADMB found when dissecting the submental area in a 72-year-old Greek male cadaver. A rare variant was recognized in the submental area constituted by a combination of bilateral asymmetry of the ADMB with unilateral absence of the intermediate tendon. The complex variant caused an obvious morphological asymmetry in the submental area. Such muscular variations may alter the surgical approach to the submental region. Clinicians involved in the treatment of this area should be aware of any possible variant, particularly when dealing with neck mass patients.

Highlights

The digastric muscle (DM), located in the suprahyoid region, consists of an anterior and a posterior digastric belly (ADMB and PDMB), each of them arising from different embryological precursors and supplied by different nerves
The anterior digastric muscle belly (ADMB) is innervated by the mylohyoid nerve, while the PDMB is supplied by the facial nerve
The ADMB and PDMB are converged to the intermediate tendon (IMT) connecting with the hyoid bone (HB) through a fascial sling closely associated with the stylohyoid muscle (SHM) insertion

Summary

Introduction

The digastric muscle (DM), located in the suprahyoid region, consists of an anterior and a posterior digastric belly (ADMB and PDMB), each of them arising from different embryological precursors and supplied by different nerves. The ADMB was constituted of three portions: a larger bulky ADMB atypically originated from the inferior mandibular rim, characterized as accessory belly; the main ADMB, smaller in size that typically originated from the digastric fossa; and a third thinner muscle bundle formed in the midline over the MHM raphe. Yellow asterisks show the left ADMBs. FA-facial artery, SBMA- submental artery, SHM-stylohyoid muscle, PDMB-posterior digastric muscle belly, HB-hyoid bone. The main left-sided ADMB possessed two origins, one larger extended over the inferior mandibular rim, and a separate smaller one originating from the digastric fossa Both parts merged further, forming a common belly and typically attached partially to the anterior end of the IMT and partially to the commencement of the fibrous band (Figure 4). The yellow asterisks show the right ADMBs. FA-facial artery, SHM-stylohyoid muscle, PDMB-posterior digastric muscle belly, HB-hyoid bone, FB-fibrous band, point of attachment of the pennated muscle fibers

Discussion

Conclusions

Disclosures

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