ACB 334 Lecture Notes - Lecture 8: Internal Arcuate Fibers, Cranial Nerve Nucleus, Upper Motor Neuron

• School: U of S
• Department: Anatomy and Cell Biology
• Course: ACB 334
• Professor: Jen Chlan

Document Summary

Cn xii (hypoglossal somatic motor intrinsic muscles of the tongue (one modality) nerve) (gse) Major function below the tongue; innervates almost all of the muscles of the tongue. Upper motor neuron is contralateral to lower motor neuron. Upper motor neuron: tongue deviate opposite lesion (toward weak side) Lower motor neuron: tongue deviate to same side of lesion: hemiatrophy, fasciculation. Found in the cervical sc at the lateral horns. Goes inside the foramen magnum and exits jugular foramen w/ cn ix and x. Some people think that the cranial component of the accessory nerve is the nucleus ambiguous. Test: turn head or lift shoulder against resistance (applying resistance is important!) Umn innervates ipsilateral scm and contralateral trapezius: head slightly rotated toward lesion and weak shoulder contralateral to lesion. Lmn innervates both ipsilateral scm and trapezius: head slightly rotated toward lesion and weak shoulder ipsilateral to lesion. Parasympathetic above splenic flexure nerve) (gve: somatic sensory.