Hypoglossal Nerve
Introduction[edit | edit source]
It is the 12th cranial nerves that originate from the medulla obligate of the brain stem. It is mainly an efferent nerve for the tongue musculature.
innervation[edit | edit source]
It gives only somatic motor innervation for all extrinsic and intrinsic muscles of the tongue except the palatoglossus, innervated by the vagus nerve.
examination[edit | edit source]
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[edit | edit source]
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.
References[edit | edit source]
1/Catala M, Kubis N. Gross anatomy and development of the peripheral nervous system. Said G, Krarup C, editors. Handb Clin Neurol. 2013;115:29–41. 2/Lin HC, Barkhaus PE. Cranial nerve XII: the hypoglossal nerve. Semin Neurol. 2009;29(1):45–52.
