Cranial Nerves_ Medulla Flashcards
Closed medulla (nuclei) –>
- caudal end of IVth ventricle
- Inferior olivary nucleus or complex
- Nucleus cuneatus, n. gracilis
- Hypoglossal nucleus
- Spinal Trigeminal Nucleus (Spinal nucleus of V)
Close medulla (tracts) :
- pyramids •medial lemniscus
- spinothalamic tracts (spinal lemniscus)
- internal arcuate fibers
- ventral trigeminothalamic tract • spinal trigeminal tract
- fasciculus cuneatus, f. gracilis • dorsal spinocerebellar tract
- medial longitudinal fasciculus (MLF)
- cuneocerebellar tract [medial vestibulospinal tract]
- lat. vestibulospinal tract • hypoglossal nerve fibers
Open medulla (nuclei) : caudal end of IVth ventricle –>
- pontomedullary junction
- inferior olivary nucleus
- spinal nucleus of V • hypoglossal nucleus
- dorsal motor nucleus of the • • • Vagus (parasympathetic)
- nucleus ambiguus (lower motor neurons for CN IX and X)
- vestibular nuclei (medial and inferior)
- dorsal, ventral cochlear nucleus
Open medulla tracts:
- Pyramids lat. vestibulospinal tract
- medial lemniscus
- inferior cerebellar peduncle
- hypoglossal nerve fibers • olivocerebellar fibers
- ventral trigeminothalamic tract • lateral spinothalamic tract
- med. vestibulospinal tract (MLF) • spinal tract of V • medial longitudinal fasciculus
Hypoglossal nerve (CN XII) =
is a motor nerve that supplies both the intrinsic and extrinsic muscles of the tongue.
The cell bodies of the lower motor neurons are in the hypoglossal nucleus, located near the __________ of the medulla (ventral to the central canal or ______________).
midline
4th ventricle
The axons pass inferolateral next to the _______________________________ to exit the medulla as rootlets in the ventrolateral (____________) sulcus.
medial lemniscus and pyramid
preolivary
Corticobulbar fibers (cortical control; upper motor neurons) arise from the _________ region of the precentral gyrus (Primary motor cortex) and descend with the corticospinal tract to the medulla where most of the fibers cross the midline and synapse in the _______________________ hypoglossal nucleus
tongue
contralateral
The _______________ nucleus receives indirect sensory information from solitary nucleus (taste) and sensory trigeminal nuclei (bolus of food in the oral cavity) by way of multisynaptic connections in the ____________________. This reflex pathway controlling the tongue is involved in swallowing, suckling and chewing.
hypoglossal
reticular formation
Clinically, a lower motor neuron lesion of the hypoglossal nerve or nucleus results in paralysis and muscle wasting of both the intrinsic and extrinsic muscles on the __________________ side.
ipsilateral
Upon protrusion of the tongue, it deviates toward the side of the lesion due to the unopposed action of the intact _________________________ muscle.
contralateral genioglossus
What is dysarthria.
Patients have difficulty with eating and speaking
An upper motor neuron lesion that occurs at a level prior to the crossing, results in:
weakness of only the extrinsic muscles (primarily genioglossus) on the side contralateral to the site of the lesion.
Which way will the tongue deviate upon voluntary protrusion in this case?
???
The _________________ nerve is important in identifying the level of lesions (strokes) in the medulla.
hypoglossal
A stroke of a paramedian branch of the anterior spinal artery may result in combinations of damage to the:
hypoglossal nerve fibers
adjacent pyramid
medial lemniscus and ventral trigeminothalamic tract
The result (of a stroke of a paramedian branch of the anterior spinal artery) is a lower motor neuron symptom involving the tongue (deficit is noted ipsilateral or contralateral?) and upper motor neuron symptoms involving the ____________ (deficit is noted ipsilateral or contralateral?).
tongue
pyramid
What sensory deficits may also accompany the motor signs in this example?
???
This type of combination of lower and upper motor neuron signs that are demonstrated on opposite sides of the neuraxis occur where a motor cranial nerve exits along the:
This combination of symptoms is called an:
midline adjacent to the descending corticospinal fibers
alternating hemiplegia.