Why can the middle crease / groove of the bottom lip deviate to the side? Can this be because of someone speaking to one side, the mandible (lower jaw) being deviated to the side, or congenital?
Most people have a lot of assymetries in their face because of the skeletal structure and teeth. In turn this creates different tensions as the muscles and tendons will lay differently.
The skeletal/teeth assymytries are due to 3 things:
- being born that way
- Preferring one side to chew on/ sleeping with clenched teeth only on one side
- Sleeping on one side of the head much longer
In the same person you will probably find the eye that the mouth goes to look more sunken in and the other eye look more droopy. If this is the case, you will also see that the cheekbone of the person with the sunken in eye pokes out more than the other side. Also the whole top of the head will tilt toward the droopy side.