A 38 year old man confides to his physician that he is experiencing erectile dysfunction. After a thorough evaluation the physician finds no organic basis for the symptoms and then prescribes tadalafil. Tadalafil inhibits phosphodiesterase type 5 and causes tumescence. Venous blood exiting the tissues impacted by the prescribed medication will first enter which of the following ?

The deep dorsal vein(2) of the penis drains blood from the erectile tissues. The external pudendal vein(1) receives blood from the skin and subcutaneous tissues of the penis but not the erectile tissues. The internal pudendal veins(3) do not directly receive blood from the erectile tissues. Small veins of the deep dorsal vein may communicate with the internal pudendal vein in the pelvis. The superficial dorsal vein(4) of the penis drains the skin and subcutaneous tissues of the penis It joins the external pudendal vein which, in turn, joins the great saphenous vein. Note: Deep penile (Buck's) fascia separates - deep dorsal vein (and aery) lying deep and superficial dorsal vein (and aery) lying superficial to it.