Table 6. Characteristics of common variations of the digastric muscle documented in the literature.

Description of variation of digastric muscle	Figure of variation	Sources in the literature Normal
Normal
Left or right unilateral anterior accessory belly (origin: digastric fossa, insertion: ipsilateral intermediate tendon)		Yamada [5], Mori [8], Larsson and Lufkin [2], Quadros et al. [38]
Left or right unilateral anterior accessory belly (origin: digastric fossa, insertion: contralateral intermediate tendon)		Yamada [5], Mori [8], Larsson and Lufkin [2], Sakamoto and Akita [52], Liquidato et al. [43]
Left or right unilateral anterior accessory belly (origin: mylohyoid raphe, insertion: ipsilateral intermediate tendon)		Yamada [5], Liquidato et al. [43]
Left or right unilateral anterior accessory belly (origin: digastric fossa, insertion: middle part of the hyoid bone)		Sargon and Celik [19], Andreo et al. [50], Sargon et al. [22], Guelfguat et al. [24]
Two left or right unilateral anterior accessory bellies (origin: digastric fossa, insertion: first accessory belly-contralateral intermediate tendon, second accessory belly-ipsilateral intermediate tendon)		Holibková and Machálek [21]
Bilateral anterior accessory bellies (origin: digastric fossa, insertion: ipsilateral intermediate tendons)		Yamada [5], Mori [8], Holibková and Machálek [21], Sargon et al. [22], Mascaro et al. [51], Sakamoto and Akita [52], Bakirci et al. [32]
Bilateral anterior accessory bellies (origin: digastric fossa, insertion: contralateral intermediate tendons, “cross type”)		Yamada [5], Mori [8], Komatsu et al. [47], Andreo et al. [50], Sarikcioglu et al. [20], Sargon et al. [22], Aktekin et al. [27], Sakamoto and Akita [52], Liquidato et al. [43], Kim et al. [12]
Bilateral anterior accessory bellies (origin: digastric fossa, insertion: mylohyoid raphe)		Loukas et al. [30], Liquidato et al. [43], Kyung et al. [36]
Bilateral anterior accessory bellies (origin: mylohyoid raphe, insertion: ipsilateral intermediate tendons)		Yamada [5], Mori [8], Komatsu et al. [47], Sato et al. [48], Peker et al. [23], Yüksel and Yüksel [25], Sakamoto and Akita [52], Reyes et al. [34]
Multiple bilateral anterior accessory bellies (two or more number of accessory bellies on each side, origin: digastric fossa, insertion: ipsilateral intermediate tendons or hyoid bone)		Sakamoto and Akita [52]
Bilateral anterior accessory bellies (origin: one side-mylohyoid raphe, the other side-digastric fossa, insertion: ipsilateral intermediate tendons)		Turan-Ozdemir et al. [29]