SG SHOT/Shutterstock
Steve Jacques
Leicester Medical School, UK
As an anatomist, I have often wondered about yawning, specifically the nerves that are involved in this process.
Most of the nerve supply to the head comes from the cranial nerves, which emerge directly from the brain. There are 12 classically described cranial nerves and the one that has the most to do with yawning is the facial nerve.
This supplies many muscles and stimulates secretion from glands in the head. I am sure that it is no coincidence that it supplies the following specific structures: the orbicularis oculi muscle (the one that closes the eyes), …