See cranial nervesTwelve pairs of nerves (for the right and left sides of the body) that pass directly from the brain to carry signals directly to and from the body, as opposed to signals which pass to and from the brain via the spinal cord. A neurological examination record will often include a phrase starting with “cranial nerve examination revealed . . . .”.. The lowermost of these nerves come off the lower part of the brain stemThis is the most primitive part of the brain, connecting the rest of the brain to the body, via the spinal cord. In addition to feeding signals to and from such “higher centres”, the brain stem contains a number of important control centres, regulating vital functions such as breathing and blood pressure. and are vulnerable to damage during surgery on the posterior fossaThat part of the cranial cavity that lies below the tentorium and which contains the brain stem and the cerebellum., including upon Chiari malformations. Bodily functions such as swallowing and speech can then potentially be affected.