Rathke, Martin Heinrich (1793–1860),
German anatomist. Rathke is regarded as one of the founders of modern embryology. In his early researches he discovered embryonic precursors of gills in the embryos of higher animals that lack gills as adults. He is best known for his discovery of branchial clefts and branchial arches in the embryos of birds and land animals. He followed the embryological history of these structures and found that the branchial clefts disappear eventually and that the blood vessels adapt themselves to the lungs. He also described and compared the development of the air sacs in birds and the larynx in birds and mammals. In 1838 he published an important study of the pituitary gland and in the following year discovered a diverticulum arising from the embryonic buccal cavity. This embryonic structure is now known as Rathke's pouch.