Alimentary and respiratory systems of the 18-mm embryo.
Keywords: adenohypophysis, appendix, arytenoid swelling, auditory tube and primitive tympanic cavity, bronchopulmonary bud(s), caudal parathyroid bud (3), cecum, cloacal membrane, dorsal pancreatic duct, duodenum, epiglottis, esophagus, external nostril, gall bladder, greater curvature of stomach, greater thymic bud, hepatic duct(s), hindgut, larynx, left primary bronchus, liver outline, lung sac outline, mesonephric duct, metanephric duct, midgut caudal limb, midgut cranial limb, mouth, neurohypophyseal bud, palatine fossa (pouch 2), primary palate, primitive choana, primitive nasal cavity, primitive pharynx, rectum, rostral parathyroid bud (4), spleen, suprarenal gland, thyroid gland, trachea, umbilical loop of midgut, urogenital sinus, urorectal septum, ventral pancreatic duct
Source: Atlas of Human Embryos.