It is thought that a number of specific nerves in the spinal cord at the back of the neck control hiccups. When something triggers these nerves - eating too quickly, for example - a signal is sent to the phrenic nerve, which controls the diaphragm. The diaphragm signals back to the hiccup center and hiccups begin. Within a split second, a structure called the glottis closes off the windpipe, producing the characteristic sound of a hiccup.

Hiccups, or hiccoughs as some people call them, is a...