|Facial Nerve Clinical Notes and Interpretation
- Cortical lesions are contralateral because facial nerve muscles receive innervation from both hemispheres.
- Brainstem lesions are ipsilateral .
- The upper facial nucleus receives bilateral innervation to the muscles of the upper quadrant of the face, but the lower facial nucleus receives only contralateral innervation.
- A PNS lesion will result in weakness in the ipsilateral facial muscles and loss of taste from the ipsilateral anterior two-thirds of the tongue.
- A PNS lesion is differentiated from a CNS dysfunction in that a patient with a CNS lesion will retain the ability to wrinkle the forehead or raise the eyebrows.