Micrognathia :
Micrognathia is a severely deficient jaw, which most commonly affects the mandible. It is not uncommon to see individuals having a very small mandible. One of the main causes of this condition is the use of forceps during birth where the baby is pulled out by clamping a pair of forceps on either side of the head. If the joint in this area, called the temperomandibular joint is badly bruised, the mandible does not develop. Sometimes this condition is also associated with congenital heart disease.