Facial nerve palsy

Definition:

Facial paralysis caused by pressure on the facial nerve while the infant is in the uterus or being delivered.

Causes, incidence, and risk factors:

Damage to the facial nerve just before or at the time of delivery may cause paralysis to the same side of the face stimulated by the damaged nerve. The entire side from the forehead to the chin may be involved in severe cases. The most common form involves only the lower branch of the facial nerve and is seen only when the infant cries. The lower lip fails to pull down on the affected side giving the mouth an unbalanced appearance. Generally the nerve has been damaged by pressure rather than the nerve fibers torn, in which case a return to normal occurs over the next few weeks to months.