Conus arteriosus

The conus arteriosus (Infundibulum; Right ventricular outflow tract) is the smooth-walled outflow tract of the right ventricle ventral and slightly cranial to the supraventricular cres that leads to the pulmonary trunk.

It is a cranial, funnel-shaped part of the right ventricle bounded by:

• Caudal boundary: supraventricular crest (crista supraventricularis)

• Cranial boundary: pulmonary valve (valva trunci pulmonalis)

• Medial wall: part of the interventricular septum

• Lateral wall: free wall of the right ventricle

• The conus arteriosus is characterized by relatively smooth internal walls, in contrast to the trabeculated inflow part of the right ventricle. The smoothness facilitates laminar blood flow toward the pulmonary valve.

At its cranial end, the conus arteriosus leads to the pulmonary orifice, guarded by the pulmonary valve, which consists of three semilunar cusps (right, left, and intermediate). These prevent backflow of blood into the ventricle during diastole.