The mechanism of alteration of endotracheal tube position with movement of the head and neck in the neonate was studied in a term newborn cadaver. The infant was intubated and serial radiographs were obtained with the head and neck in different positions. We propose that the skull acts as a lever arm from the anterior end of the maxilla to the first cervical vertebra. The fulcrum for movement of this lever arm is the upper cervical spine. Movement of the endotracheal tube in the trachea is directed by the maxillocervical lever arm when the skull and upper cervical spine are flexed, extended, or rotated.