Facial weakness finding
This patient with a right lower motor neuron facial weakness has the inability to raise the right eyebrow and weakness of right eye closure and the right lower face.
[Doctor] Please raise your eyebrows. Please close your eyes. Please smile. Thank you very much.
About facial weakness
Patients may have unilateral facial weakness affecting the entire side of the face including the forehead, eye closure and smile, or may have weakness of only the lower face with sparing of the forehead muscles and minimal weakness of eye closure. The location of the lesion differs depending upon the presentation.
Localization
Cranial nerve seven originates in the pons. It innervates all the ipsilateral muscles of facial expression and, thus, the lower motor neuron lesion of cranial nerve seven results in a complete hemifacial paralysis. The motor cortex, via the corticobulbar tract, innervates the muscles of the upper face bilaterally, leading to sparing of the forehead in a patient with a unilateral upper motor neuron lesion.