See muscle.
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in·ter·os·se·us .in-tər-'äs-ē-əs n, pl -sei -ē-.ī any of various small muscles arising from the metacarpals and metatarsals and inserted into the bases of the first phalanges:
a) DORSAL INTEROSSEUS
b) PALMAR INTEROSSEUS
c) PLANTAR INTEROSSEUS
Medical dictionary. 2011.