Interosseus muscle atrophy (Human Phenotype Ontology term HP_0007181) is atrophy of the interosseus muscles (including the palmar interossei that lie on the anterior aspect of the metacarpals, the dorsal interosseus muscles of the hand, which lie between the intercarpals, the plantar interosseus muscles, which lie underneath the metatarsal bones, and the dorsal interossei, which are located between the metatarsal bones. Also known as: Interosseous muscular atrophy.