Cineroentgenographic and electromyographic studies of Eustachian tube function

To determine the opening and closing process of the Eustachian tube during swallowing, the simultaneous recording of cineroentgenograms and electromyograms (EMG) was carried out in three monkeys. It was revealed that synchronous with the activity of the tensor veli palatini muscle, the cartilaginous tube opened for a very short time (ca. 250 ms) by an outward movement of its lateral wall. On the other hand, the pharyngeal orifice of the tube dilated for a relatively long time synchronous with the activity of the levator veli palatini muscle. These time lags between two parts of the tube seemed to help the pumping function of the tube.