abnormal muscle morphology muscular atrophy acquired diminution of muscle tissue associated with wasting as from death and reabsorbtion of cells, diminished cellular proliferation, decreased cellular volume, pressure, ischemia, malnutrition, reduced function or malfunction, or hormonal changes; occurs with age, immobilization, weightlessness, malnutrition or denervation muscle atrophy MPheno.ontology MP:0002269