Variations of the digastric muscle in children: Magnetic resonance imaging evaluation

Abstract

Objective: The digastric muscle is an important component of the suprahyoid region and may demonstrate various morphological variations, particularly in its anterior belly. Data regarding digastric muscle morphology in the pediatric population based on magnetic resonance imaging (MRI) remains limited. This study aimed to evaluate digastric muscle thickness and anatomical variations in children using MRI.

Materials and Methods: In this retrospective cross-sectional study, head and neck MRI scans of 30 pediatric patients (mean age 12±2.3 years) without cervical pathology were analyzed. Thickness of the anterior and posterior bellies of the digastric muscle was measured bilaterally on axial images. Morphology and symmetry were evaluated on coronal and sagittal planes. Variations were classified as accessory muscle slips, double anterior belly, or asymmetric thickness. Side-to-side comparisons were performed using paired t-tests.

Results: No significant difference was observed between right and left anterior belly thickness (4.2±0.6 mm vs 4.1±0.5 mm; p=0.32) or posterior belly thickness (3.8±0.5 mm vs 3.9±0.6 mm; p=0.28). Digastric muscle variations were identified in 9 patients (30%). The most frequent variation was asymmetric thickness (16.7%), followed by accessory muscle slips (10%) and double anterior belly (3.3%). Most variations were localized in the anterior belly.

Conclusions: The digastric muscle in children demonstrates substantial bilateral symmetry on MRI. Variations are predominantly located in the anterior belly and can be reliably identified with multiplanar MRI evaluation. Awareness of normal digastric muscle variants is important in pediatric head and neck imaging to avoid misinterpretation of submental lesions.