Vascular sinus generally refers to the venous sinus which is the enlarged portion of the vein that appears at intervals of length, this condition is generally caused by the structure of the valve tissue within the vein where there are bamboo-like changes along the distribution of the vein. It is a normal structure, so there is no need to be nervous when the sinus is present or found, as this is a completely physiological change. However, if the sinus is significantly dilated and accompanied by tortuous and dilated veins, it suggests that damage to the valve function may have occurred resulting in tortuous and dilated veins, also known as varicose veins.