Variations in the Number of Pulmonary Veins Draining into Left Atrium and its Clinical Significance

ABSTRACT

Pulmonary veins, normally two on each side bring oxygenated blood from lungs to left atrium. During early embryonic life, absorption of pulmonary venous network by the left primitive atrial chamber results in opening of four pulmonary veins which drain independently into its chamber. The extent of absorption and hence, the number of pulmonary veins which open into left atrium may vary