Nosebleeds or epistaxes 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.
Anterior nosebleeds are common in dry climates or during the winter months when dry, heated indoor air dehydrates the nasal membranes. Dryness may result in crusting, cracking, and bleeding. This can be prevented by placing a light coating of petroleum jelly or an antibiotic ointment on the end of a fingertip and then rub it inside the nose, especially on the middle portion of the nose (the septum).
More rarely, a nosebleed can begin high and deep within the nose and flow down the back of the mouth and throat even if the patient is sitting or standing.
Obviously, when lying down, even anterior (front of nasal cavity) nosebleeds may seem to flow toward the back of the throat, especially if coughing or blowing the nose. It is important to try to make the distinction between the anterior and posterior nosebleed, since posterior nosebleeds are often more severe and usually require a physician’s care. Posterior nosebleeds are more likely to occur in older people, persons with high blood pressure, and in cases of injury to the nose or face.