myelodysplasia /mī′əlōdisplā″zhə/ [Gk, myelos + dys, bad, plassis, formation] , 1. a general designation for the defective development of any part of the spinal cord. The term is used primarily to describe abnormalities without gross superficial defects, especially of the lower segment, specifically spina bifida occulta. 2. dysplasia of the myelocytes and other elements in bone marrow.
