*If epistaxis continues for days even after using posterior& anterior packs , it may be necessary to clip the feeding arteries to the nose. Maxillary artery from the external carotid artery system feeds the lower part of the nose and the ethmoidal artery from the internal carotid artery system feeds the upper part of the nose." (ref:32, logan turner 10th)
*Retro columellar vein: runs verticaly downward just behind the columella , crosses the floor of nose and joins venous plexus on the lateral wall. Its the common site of venous bleeding in young individual.