Brainstem and Corticobulbar Pathways Flashcards
Which cranial nerves carry autonomics as one of their modalities?
CN III
CN VII
CN IX
CN X
Which cranial nerves are associated with the medulla oblongata?
Hypoglossal n.
Vagus n.
Glossopharyngeal n.
Axons of motor neurons from hypoglossal n. pass anteriorly in the medulla along the lateral aspect of the _____ ____ and the _______, continuing via the hypoglossal canal
Medial lemniscus; pyramid
What a. supplies the nucleus of the hypoglossal n?
Penetrating branches of anterior spinal a.
Muscles innervated by hypoglossal n.
Intrinsic tongue mm
Hyoglossus
Palatoglossus
Genioglossus
Result of lesions to hypoglossal nucleus
Tongue deviates contralateral to lesion when protruded
Result of injury to left hypoglossal n. (LMN)
Protruded tongue deviates left (ipsilateral to lesion)
Muscle atrophy and flaccid paralysis
Which n. sits in intermediate position of medulla oblongata between midline and lateral medulla?
Vagus n.
2 ganglia of vagus n. immediately external to jugular foramen — what are they and what cell bodies do they contain?
Superior ganglion = cell bodies of somatic afferent fibers
Inferior ganglion = cell bodies of visceral afferent fibers
What 2 nuclei are associated with motor fibers of vagus n.?
Dorsal motor nucleus of vagus (visceral efferent parasympathetics — preganglionic)
Nucleus ambiguus (somatic efferents)
Visceral efferent parasympathetic preganglionic fibers from vagus n. (Dorsal motor nucleus) targets the intramural ganglia of what visceral structures?
Trachea
Bronchi
Heart
Proximal GI tract (to sigmoid flexure of colon)
Nucleus ambiguus contains somatic efferent fibers of vagus n. What targets do these axons contact?
Pharyngeal and laryngeal targets
Skeletal m. in upper half of esophagus
2 types of sensory fibers associated with vagus n.
Somatic afferent input = pain and temp from small area on ear and part of external auditory meatus + dura of posterior cranial fossa
Visceral afferent and taste
Somatic afferent fibers of vagus n. enter via medulla to join the _____ tract and synapse in the corresponding nucleus
Spinal trigeminal
Visceral afferent and taste fibers of vagus n. have central processes that enter the ____ tract and terminate in the surrounding caudal corresponding nucleus
Solitary
CN X lesions at the root are also known as ______ syndrome.
What are the symptoms?
Jugular foramen syndrome
Dysphagia
Dysarthria
Weakness+slight drooping of ipsilateral palatal arch
Contralateral uvula deviation, acutely on phonation
[no lasting symptoms related to visceromotor/autonomic dysfunction]
Effect of nucleus ambiguus damage
Weakness of contralateral palatal arch mm
Slight drooping of contralateral palatal arch
Ipsilateral uvula deviation on attempted phonation
Somatic afferent fibers of the glossopharyngeal n. originate from small area on pinna and external auditory canal, and posterior 1/3 tongue. Cell bodies are in the _____ ganglion and fibers proceed via the ____ tract to the corresponding nucleus
Superior; spinal trigeminal
Visceral afferent fibers of the glossopharyngeal n. convey info from what structures?
Parotid gland
Oropharynx
Carotid body
Visceral afferent fibers of glossopharyngeal n. have cell bodies in the _____ ganglion which proceeds via _____ tract and targets the corresponding nucleus
Inferior; solitary
Lesions to the glossopharyngeal n. may affect what other nerve roots?
Vagus n
Accessory n.
[at jugular foramen]
Result of glossopharyngeal n. damage at jugular foramen
Diminished sense of taste from posterior tongue
Loss of ipsilateral stylopharyngeus m. contraction — gag reflex affected
Condition characterized by attacks of intense idiopathic pain arising from sensory distribution of CN IX
Glossopharyngeal neuralgia
Lesions of the medial medulla affect what structures?
Hypoglossal n.
Pyramid
Medial lemniscus
Effect of lesions of medial medulla
Ipsilateral tongue deviation and contralateral hemiparesis (CST involvement)
Contralateral loss of PCMLs
Inferior alternating hemiplegia (medial medullary or Dejerine syndrome)