Anatomy of the intramural venous sinuses of the right atrium and their tributaries.

A precise knowledge of the mode of opening of the vv. on the anterior wall of the right ventricle, i.e., directly or by means of intramural venous sinuses in the right atrium, is of fundamental importance for cardiologic methods of examination and treatment. We dissected 32 hearts obtained from cadavers belonging to adult individuals of unknown age and sex, fixed and stored in formalin. A total of 151 veins were detected for the 32 cases. The following distribution was observed: 33 right marginal vv. (m) in 29/32, 59 anterior vv. of the right ventricle (a) in 29/32, 29 vv. of the arterial cone (c) in 26/32, 17 posterior vv. of the cone (p) in 17/32, and 13 Zuckerkandl vv. (z) in 13/32. Of these veins, a) 4 m emptied into the right atrium, with one of them forming a bifurcation and emptying twice; b) 4 m continued into a small cardiac v.; c) 6 collector vv. present in 4/32 cases emptied into the right atrium and received 2 m, 5 a, 2 c, 3 p and 2 z; d) 35 intramural venous sinuses were present in 30/32 or 94% of cases emptied into the right atrium and received 15 m, 26 a, 5 c, 4 p, 3 z and 32 collector vv., into which 8 m, 28 a, 22 c, 10 p and 8 z drained. In conclusion, these venous sinuses are normal and are very important for venous drainage.