Hypoglossal Nerve

Introduction

It is the 12 cranial nerves that originate from the medulla obligate of the brain stem.

innervation

it gives only somatic motor innervation for all extrinsic and intrinsic muscles of the tongue except the palatoglossus, innervated by the vagus nerve.

examination

Examining the hypoglossal nerve involves observation of the primary innervation target of the nerve; the tongue. The three observable aspects of the tongue are strength, bulk, and dexterity. Special attention is given when the tongue is weak, atrophied, moving abnormally, or impaired.

<ref>phtsiotutors. Cranial Nerve 12 | Hypoglossal Nerve Assessment for Physiotherapists.available from https://www.youtube.com/watch?v=e6X8vMYTSHs

lesion

1/ UMNL: unilateral: deviation of the tongue to the opposite side of the lesion. bilateral: inability to protrude the tongue. note in both cases there is no wasting or fasciculation 2/LMNL: unilateral: deviation of the tongue to the side of the lesion.

bilateral:  inability to protrude the tongue.

note in both cases there is wasting and fasciculation.