[1] The truncus arteriosus and bulbus cordis are divided by the aorticopulmonary septum.

The truncus arteriosus gives rise to the ascending aorta and the pulmonary trunk.

The caudal end of the bulbus cordis gives rise to the smooth parts (outflow tract) of the left and right ventricles (aortic vestibule & conus arteriosus respectively).

[4][5][6] Other pathologies of the truncus arteriosus include transposition of the great vessels (arteries in this case), and tetralogy of Fallot.

[7] This article incorporates text in the public domain from page 514 of the 20th edition of Gray's Anatomy (1918)