part of mammary gland breast lobe 2010-05-18T11:46:47Z BTO:0004718 BrendaTissueOBO The 15 to 20 separate portions of the mammary gland that radiate from the central area deep to the nipple like wheel spokes and comprise the body of the mammary gland; each is drained by a single lactiferous duct. lobe of breast lobe of mammary gland lobi glandulae mammariae lobus glandulae mammariae mgr