The right ventricle, ventriculus dexter, has the shape of a triangular pyramid, the base of which, facing up, is occupied by the right atrium, with the exception of the upper left corner, where the pulmonary trunk emerges from the right ventricle, truncus pulmonalis. The ventricular cavity is divided into two sections: the department closest to the ostium atrioventriculare and the anterior-superior section closest to the ostium trunci pulmonalis, conus arteriosus, which continues into the pulmonary trunk.
Ostium atrioventriculare dextrum, leading from the cavity of the right atrium to the cavity of the right ventricle, is equipped with a tricuspid valve, valva atrioventricularis dextra s. valva tricuspidalis, which makes it impossible for blood to return to the atrium during systole; blood is sent to the pulmonary trunk. Three valve leaflets are designated by their location as cuspis anterior, cuspis posterior, and cuspis septalis. The free edges of the leaf turn into the ventricle. Attached to them are thin tendon threads, chordae tendineae, which at their opposite ends are attached to the tips of the papillary muscles, the musculi papillares. The papillary muscles are cone-shaped muscular eminences, with their tips projecting into the cavity of the ventricle and passing into its walls with bases. In the right ventricle, there are usually three papillary muscles: the anterior, the largest in size, gives rise to tendon threads to the anterior and posterior cusps of the tricuspid valve; the posterior one, smaller in size, sends the tendinous filaments to the posterior and septal flaps and, finally, m. papillaris septalis, not always available muscle, gives tendon threads usually to the anterior cusp. In case of its absence, the filaments arise directly from the wall of the ventricle. In the area of the conus arteriosus, the wall of the right ventricle is smooth, the fleshy trabeculae, trabeculae carneae, enter the rest of the length.
Blood from the right ventricle enters the pulmonary trunk through the ostium trunci pulmonalis, equipped with a valve, valva trunci pulmonalis, which prevents the return of blood from the pulmonary trunk back to the right ventricle during diastole. The valve consists of three semi moon flaps. Of these, one is attached to the anterior third of the circumference of the pulmonary trunk (valvula semilunaris anterior) and two to the back (valvulae semilunares dextra et sinistra). On the inner free edge of each flap there is a small nodule in the middle, nodulus valvulae semilunaris, on the sides of the knot the thin marginal segments of the flap are called lunulae valvulae semilunaris. Nodules contribute to a tighter closing of the flaps.