Most nosebleeds or epistaxis begin in the lower part of the septum, the semi-rigid wall that separates the two nostrils of the nose. The septum contains blood vessels that can be broken by a blow to the nose or the edge of a sharp fingernail. Nosebleeds coming from the front of the nose or anterior nosebleeds often begin with a flow of blood out one nostril when the patient is sitting or standing.
