Point 14 Intro Pathway Deficit Note Overview Problems Contents Anatomy

The motor nucleus VII contains motor neurons (branchiomotor) that innervate the muscles of facial expression including the orbicularis oculi (CLOSES eyelid), the stapedius, the stylohyoid and the posterior belly of the digastric. Neurons comprising motor VII possess axons that pursue a rather circuitous route in order to exit the brain stem. Initially they pass dorsally and medially to loop over the abducens nucleus. The fibers then course ventrally and laterally to exit the brain stem. The bump in the floor of the fourth ventricle caused by the motor fibers of C.N. VII looping over the abducens nucleus is called the FACIAL COLLICULUS.