Sexuality
Some people may sneeze during the initial phases of sexual arousal. Doctors suspect that the phenomenon might arise from a case of crossed wires in the autonomic nervous system, which regulates a number of functions in the body, including "waking up" the genitals during sexual arousal. The nose, like the genitals, contains erectile tissue. This phenomenon may prepare the vomeronasal organ for increased detection of pheromones.A sneeze has been compared to an orgasm, since both orgasms and sneeze reflexes involve tingling, bodily stretching, tension and release. On this subject, sexologist Vanessa Thompson from the University of Sydney states, "Sneezing and orgasms both produce feel-good chemicals called endorphins but the amount produced by a sneeze is far less than an orgasm. "According to Dr. Holly Boyer from the University of Minnesota, there is a pleasurable effect during a sneeze, where she states, "the muscle tension that builds up in your chest causes pressure, and when you sneeze and the muscles relax, it releases pressure. Anytime you release pressure, it feels good...Theres also some evidence that endorphins are released, which causes your body to feel good". Endorphins induce the brains reward system, and because sneezes occur in a quick burst, so does the pleasure. In non-humans
Sneezing is not confined to humans or even mammals. Many animals including cats, dogs, chickens and iguanas sneeze. African wild dogs use sneezing as a form of communication, especially when considering a consensus in a pack on whether or not to hunt. Some breeds of dog are predisposed to reverse sneezing.
Pneumocephalus is the presence of air or gas within the cranial cavity. It is usually associated with disruption of the skull: after head and facial trauma, tumors of the skull base, after neurosurgery or otorhinolaryngology, and rarely, spontaneously. Pneumocephalus can occur in scuba diving, but is very rare in this context. If there is a valve mechanism which allows air to enter the skull but prevents it from escaping, a tension pneumocephalus can occur (similar to what can happen in a tension pneumothorax). CT scans of patients with a tension pneumocephalus typically show air that compresses the frontal lobes of the brain, which results in a tented appearance of the brain in the skull known as the Mount Fuji sign. The name is derived from the resemblance of the brain to Mount Fuji in Japan, a volcano known for its symmetrical cone. In typical cases, there is a symmetrical depression near the midline (such as the crater of a volcano), due to intact bridging veins. Its occurrence seems to be limited to tension pneumocephalus (not occurring in pneumocephalus without tension). The sign was first described by a team of Japanese neurosurgeons.Pneumocephalus has also been shown to follow neurosurgical procedures such as deep brain stimulation and hematoma evacuation (e.g., chronic subdural hematoma), where while seemingly innocuous to the patient, may cause brain shift, subsequent stereotactic inaccuracy, and even another surgical intervention.