part of part of contributes to morphology of right cardiac atrium anatomical cavity vena cava sinus FMA:13246 cavity of inflow part of right atrium UBERON:0005981 posterior right atrial cavity The portion of the cavity of the right atrium of the heart that receives the blood from the vena cavae and is separated from the rest of the atrium by the crista terminalis. sinus venarum cavarum