The facial motor nucleus is a collection of neurons in the brainstem that belong to the facial nerve cranial nerve VII. These lower motor neurons innervate the muscles of facial expression and the stapedius. The nucleus is situated in the caudal portion of the ventrolateral pontine tegmentum. Its axons take an unusual course, traveling dorsally and looping around the abducens nucleus , then traveling ventrally to exit the ventral pons medial to the spinal trigeminal nucleus. These axons form the motor component of the facial nerve , with parasympathetic and sensory components forming the intermediate nerve. The nucleus has a dorsal and ventral region, with neurons in the dorsal region innervating muscles of the upper face and neurons in the ventral region innervating muscles of the lower face.
Try out PMC Labs and tell us what you think. Learn More. Facial paralysis is one of the common problem leading to facial deformation. Bell's palsy BP is defined as a lower motor neuron palsy of acute onset and idiopathic origin.
A facial palsy is weakness or paralysis of the muscles of the face. The facial nerve arises in the pons formed as separate sensory and motor roots , before travelling in the internal acoustic meatus, very close to the inner ear. As they enter the facial canal, the two roots fuse to form a single facial nerve, before giving off intracranial branches of the greater petrosal nerve, nerve to stapedius, and chorda tympani. The facial nerve then exits the facial canal and the cranium via the stylomastoid foramen. The first extracranial branches given off are the posterior auricular nerve, nerve to digastrics, and nerve stylohyoid.