Table 3.

Overview of earlier segregated muscles compared with the literature

Region	Muscle	Earlier segregation	Source
Head and neck	Extraocular (except levator palpebrae muscle)	x	NS
	Facial nervea		Gasser (1975)
Trunk	Spinalisb	x	Sato et al. (2011)
Upper limb	Triceps brachii	x	Grzonkowska et al. (2014)
	Pectoralis major	x	NS
	Forearm	x	NS
	Lumbrical	x	NS
Lower limb	Gluteal	x	Kedzia et al. (2014)

Stage 23 human embryo (56–60 days of development), specimen number 950, has been used for this table. Eight muscle(s) (groups) are notably more segregated at this stage of development than could be expected from the current literature. Sources that indicate earlier development are given in the last column.

NS, no dedicated source was found on the embryonic development of this muscle (group). Thus, the stage of muscle segregation in this specimen appears to be further developed than described in the general literature about embryonic muscle morphogenesis.

^aFacial nerve muscles: the muscles innervated by the facial nerve were not present in our specimen except for the stylohyoid and posterior belly of digastric muscle.

^bSato et al. (2011) did not identify this muscle, but Mekonen et al. (2016) did.