The jaw reflex: maturation in the neonatal period and childhood.

The onset and development of the jaw-reflex responses were studied of 54 neonates and children in up to 15 years of age. Recordings were made with standard EMG equipment. The reflex response was constantly elicited in all but one child of 35 weeks postconceptional age. The latency times showed negative linear correlation with age in the neonatal group and in the children under two years of age. The anatomical basis for the jaw reflex is already established by the 31st fetal week, and the reflex is fully developed by the age of two years. Potential clinical applications of the jaw reflex to child neurology and neonatal intensive care are discussed.