Facial Palsy and Motor Neuron Lesions

Vocabulary flashcards covering key neuroanatomical terms, facial nerve pathway organization, and clinical presentation differences between upper and lower motor neuron lesions.

Lesion

A region in an organ or tissue which has been damaged through the process of injury or disease.

Palsy

Paralysis or the loss of the ability to move.

Contralateral

The opposite side of the body to the lesion.

Epil lateral

Refers to the same side of the body as the lesion.

Seventh nerve

Also known as the facial nerve, it is located in the pons and is responsible for the muscles of facial expression.

Pons

The component of the brainstem that acts as the location of the seventh nerve or facial nerve nuclei.

Upper half of the facial nucleus

The portion of the facial nucleus that receives innervation from both the contralateral and ipsilateral motor cortex, supplying lower motor neurons to the upper facial expression muscles.

Lower half of the facial nucleus

The portion of the facial nucleus that receives innervation only from the contralateral motor cortex, supplying lower motor neurons to the lower facial expression muscles.

Upper motor neuron lesion

A lesion leading to paralysis of the contralateral lower facial musculature, presenting as an inability to smile on the affected side while preserving the ability to raise both eyebrows.

Lower motor neuron lesion

A lesion of the facial nerve leading to paralysis of the epil lateral upper and lower facial musculature, presenting as an inability to raise the eyebrow or smile on the side of the lesion.