Velopharyngeal closure and the longus capitis muscle.

The dynamic mechanism of velopharyngeal function not only in normal individuals but also in patients with velopharyngeal insufficiency, which is mainly related to cleft palate, has been the subject of considerable interest and controversy. Recently, in order to clarify velopharyngeal movement in the valvular action on phonation we examined dynamic MR images of this area taken in the transverse plane in parallel with the muscle sling of levator veli palatini. In cases in whom the closure pattern in that plane is circular, detailed observation revealed a very interesting result; that is, the longus capitis muscle, one of the group of anterior vertebral muscles, is directly involved in velopharyngeal valving function. It has not previously been reported that the longus capitis muscle acts as one of the velopharyngeal closure muscles, in addition to levator veli palatini. The present study demonstrated that contraction of the muscle contributed to velopharyngeal closure by forward movement of the pharyngeal wall.