Variations of the anterior belly of the digastric muscle: a cadaveric and meta-analysis study

Variations of the anterior belly of the digastric muscle are frequently reported in adult populations; however, the developmental timing of their appearance remains insufficiently understood. This study aimed to describe the morphology and prevalence of anterior digastric belly variations and to contextualize these findings through a meta-analysis of published anatomical studies. Twenty-six formalin-fixed human fetuses (13 male, 13 female) were dissected and analyzed morphologically. Variations were classified according to De-Ary-Pires, Ary-Pires and Pires-Neto. A systematic review and meta-analysis of observational studies reporting the prevalence of anterior belly variations was conducted following PRISMA guidelines. The mean gestational age was 29.4 ± 3.58 weeks. Variations were observed in six fetuses (23.1%), all classified as type II, with no association with sex or gestational age. The meta-analysis of 16 studies (n = 787) yielded a pooled prevalence of 25.1% (95% CI: 15.5–35.9;
I² = 90.6%), with variation across geographical regions and sexes. Variations of the anterior belly of the digastric muscle are established during fetal development and occur at frequencies comparable to those reported in postnatal populations. These findings support a developmental origin for this anatomical variability and provide a morphological framework for future embryological and anatomical investigations of the suprahyoid region.