<prompt> Infection of lower lip first reaches blood stream through?Inferior labile arterySuperior labile arteryPterygoid plexusBrachiocephalic vein  <response>: The pathway of spread of intection from lower lip to blood is:Lip Sub mental and submandibular lymph nodes deep cervical lymph nodes Left and right jugular lymph trunk from left jugular trunk thoracic duct from right at the junction between IJV and subclavian vein IJV subclavian vein Brachiocephalic vein and two brachiocephalic vein join to form superior vena cava.Or directly, we can say infection from any tissue reached the blood stream via venous drainage rather than arterial supply. 