Halitosis is when a person produces a really bad odar from their nose and mouth. So just like morning breath but thru your nose too and all the time... EWW! :Z
Hallitosis
It would a dentist, an ENT, an internal medicine specialist, or a hepatologist depending on what the cause of the hallitosis is due to.
Diarrhea, colitis, common cold, sore throat, leukorrhea, dysentery, induces menstruation and abortion, stomach problems, hallitosis.
The correct phrase is "stinky breath" or "breath that stinks". It is called hallitosis. It may smell because they don't brush they teeth or they may have gum disease.
It is impossible for air or bacteria to get to the brain from breathing in through the nose (or mouth). The nose is not an open channel or funnel to the brain. Besides the facial bones and skull, the entire brain is enclosed. As well, the hairs in the nose filter out most dust, pollens, and germs. There is also no "funnel" from the brain or from the nose. The nasal passages meet the sinus cavities. The sinus cavities are located under the skin and bone of both cheeks and above and below both eyes. The nasal passages and the sinuses serve to warm the air we breathe in. Breathed in air travels to the back of the throat at the trachea, where air then travels down the main bronchi into the lungs. When people "nose breathe" they have less sore throats because the air is warmed in the nose and sinuses. Nose breathing reduces the number of cavities in teeth because mouth-breathing causes dry mouth; dry mouth allows bacteria on the teeth to multiply resulting in more decay. Because of more cavities, mouth-breathers have more incidence of bad breath than people who nose breathe have. However, some people have a deviated septum -- the nasal passages aren't as straight as they are in other people. Therefore, these people feel they get less air so they mouth breathe. In addition, people who have allergies or a lot of sinus infections breathe more through the mouth, especially at night time. As I stated above, people who mouth breathe end up with chronic dry mouth, tooth decay, and hallitosis more often than people who nose breathe. So, in answer to your question, no, the books are not wrong. There is no part of bone and muscle anatomy that goes straight from the nose to the brain. The only way the brain can become infected is in serious diseases, such as meningitis or infections that involve the spinal fluid. The brain is, however, suseptible to many chronic conditions or injuries, such as from Stroke. In a condition of a severely infected ear that has not been treated, the bacteria *might* soften the skull behind the ear and cause a brain infection that way. But, most ear infections are in children and are recognized early due to high fevers and pain, so treatment is begun long before the infection could get bad enough to make its way to the brain.