Unusual patterns of swallowing of this type may cause abnormal incisor positions. In the case of an untreated cleft palate, the tongue has nothing to act against during swallowing so that the bolus passes upwards into the nasal cavity. The space bounded by these 3 structures includes the anatomically defined vallecular spaces and, for simplicity, the whole storage area will simply be called the vallecula. The assumption is that the accumulation of food in the vallecula normally triggers the swallow. Clearly this accumulation is impossible in adult man because of the descent of the larynx and loss of the closed storage area.
Abdominal pressure is raised due to abdominal muscle contraction and to the descent of diaphragm.
The pylorus usually contracts to prevent any normal onward transport from the stomach. This is retching. If the intra-abdominal pressure is sufficiently high, the gastric contents may breach upper oesophageal sphincter leading to vomiting . Note that respiration ceases and the glottis closes during vomiting as a standard way of protecting the airway - unless the subject is not yet recovered from general anaesthesia or is under the influence of drugs or alcohol which may interfere with the central reflex mechanisms. Inhalation of vomit can kill and even under the best hospital conditions will produce a serious pneumonia.