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 (mĕz′ə-dûrm′, mĕs′-)
The middle embryonic germ layer, lying between the ectoderm and the endoderm, from which connective tissue, muscle, bone, and the urogenital and circulatory systems develop.

mes′o·der′mal, mes′o·der′mic adj.
References in periodicals archive ?
S: normal stem cell; E: tumor of the endodermic origin; M: tumor of the mesodermic origin; and EC: tumor of the ectodermic origin.
DIFFERENTIAL DIAGNOSIS: D/D fall into three groups of developmental errors-those of neurogenic origin-the gliomas, neurofibromas and encephaloceles, those of ectodermic origin-the pilonidal sinus and those of mesodermic origin-the hemangiomas.
Histological examination revealed a heterogeneous entity consisting of two areas: a cystic and a solid one, both comprising a randomly disposed mixture of tissues with ectodermic, mesodermic, and endodermic origins, with histological structure different from that of the filum terminale (Fig.