Medulla

Major ascending tracts in medulla

Fasciculus cuneatus, fasciculus gracilis, arcuate fibers, spinothalamic tract, trigeminothalamic tract

FUnctions of Dorsal Column/ Medial Lemniscal system

fine touch, proprioception, pressure, vibration sensations from the body to the brain.

1, 2 , 3 order neurons of Dorsal column

Dorsal Root Ganglia, Nucleus Gracilis and Cuneatus, Ventral Posterolateral nucleus of thalamus

Levels of DRG’s of Dorsal Column

Fasciculus gracilis T7 and below; Fasciculus Cuneatus - T6 and above

Decussation place in Dorsal column

Caudal medulla as Internal arcuate fibers

Lesions in Fasciculus Gracilis and Cuneatus (write first*); Lesion in Medial lemniscus

ipsilateral deficit in touch pressure, vibration; contralateral deficit

Clinical signs of lesion

Astereognosis, agraphesthesia, loss of discrimination, vibration sensation, position and movement, positive Romberg sign

Anterior spinothalamic tract function

crude touch, pressure, tickle and itch

Lateral spinothalamic tract

pain and temperature from body

Decussation in Spinothalamic tract and decussating fibers

Anterior white comissure of spinal cord; second order neurons (Lamina 1,2,3&4)

Lesion in spinothalamic tract

loss of pain and temperaure from Contralateral side of body

Trigeminothalamic pathway function

pain and temperature from face

Cells of origin of Trigeminothalamic pathway (1st order neuron)

trigeminal ganglion

Decussation of Trigeminothalamic p.

Caudal medulla, Caudal and rostral pons

Lesion in descending spinal tract of V (it’s bundle of 1 order neuron fibers that enters pons and descends)

Ipsilateral deficit in pain and temperature from face, teeth, ant.2/3 tongue and palate

lesion of trigeminothalamic tract

contralateral deficits

Major descending tracts in medulla

Pyramidal/corticospinal, medial longitudinal fasciculus, Spinal tract of V, reticulospinal, vestibulospinal, tectospinal

Lateral Corticospinal tract decussation (85%)

pyramids

Upper Motor Neurons originate in (ant.&lat. corticospinal tracts)

motor cortex

Lateral corticospinal tract terminates along… , for

entire spinal cord; movement of contralateral limbs

Anterior corticospinal tract terminates in … ,for

cervical and upper thoracic cord; bilateral control of axial and girdle muscles

Lower motor meuron of corticospinal tracts

vental horn

Corticospinal tract cells origin

Precentral gyrus, Premotor cortex,  Supplementary motor cortex

Lesion rostral to decussation (write first*); lesion caudal to decussation (in spinal cord) corticospinal tract

contralateral hemiplegia; ipsilateral hemiplegia

Does Trigeminal system (motor nucleus of V) decussate?

No, as it is a Lower Motor Neuron system

Lesion of motor nucleus of V

Ipsilateral atrophy of all muscles of mastication, opened jaw deviate ipsilaterally

External features of medulla (lower and upper parts)

Lower - encloses central canal; upper is in front of fourth ventricle

anterior surface of medulla

anterior median sulcus, pyramid, olive, anterolateral sulcus, posterolateral sulcus, pyramidal decussation, CN 9, 10, 11, 12

posterior surface of medulla, gracile tubercle, cuneate tubercle, tubere cinereum, stria medularis, inf cerebellar peduncle, vestibular area, hypoglossal area, vagal triangle,

posterior medial sulcus

Autonomic nuclei in medulla ( по идее надо знать что они делают еще) 25 slide*

Cardiovascular centers, respiratory rhythmicity centers, additional centers

Sensory and motor nuclei of cranial nerves in medulla

vestibular, glossopharyngeal, vagus, accessory, hypoglossal

Relay nuclei and what they do

nucleus gracilis and cuneatus - somatic sensory info to thalamus; olivary nuclei relay- info from spinal cord, cerebral cortex, brainstem to cerebellar cortex

Major tracts in caudal medulla

fasciculus gracilis, fasciculus cuneatus, spinal tract of V, spinothalamic tract, decussation of pyramids

other tracts in medulla

internal arcuate fibers, medial lemniscus, spinal tract of V, spinothalamic tract

Contains LMN innervating ipsilateral tongue

hypoglossal nucleus CNXII

Contains 2^nd order neurons of Trigemino- Thalamic pathway mediating pain & temp from ipsilateral face

spinal nucleus of V

Contains preganglionic parasympathetic neurons of CN X

dorsal motor nucleus of X

Contains neurons innervating smooth muscles of pharynx, & larynx

nucleus ambiguus CN IX,X,XI

contains neurons projecting to the contralateral cerebellum as climbing fibers

inferior olivary nuclei

contain 2^nd order neurons in vestibular pathway

vestibular nuclei CN VIII

◦contains 2^nd order neurons of taste pathway & sensory neurons of CN IX & X

solitary nucleus CN VII,IX,X

contain 2^nd order neurons in auditory pathway

cochlea nuclei VIII

contains diverse neurons with diverse functions

reticular formation

nuclei in medulla

hypoglossal, dorsal motor nucleus of X, solitary, nucleus ambiguus, medial vestibular, inferior vestibular, spinal nucleus of V, inferior olivary

Tracts in rostral medulla

spinal tract of V, solitary tract, spinothalamic tract, medial lemniscus, pyramid

Pyramidal decussation level tracts and structures

Lateral corticospinal tract, pyramidal decussation, lateral spinothalamic tract, spinocerebellar tract, spinal tract

lemniscal decussation level structures

nucleus gracilis, nucleus cuneatus, internal arcuate fibers, medial lemniscus

identify levels of medulla

pyramidal decussation, lemniscal decussation, inferior olivary nuclei

what we see in level of inferior olives (пж посмотрите 39 слайд)

hypoglossal nucleus, medial and inferior vestibular nuclei, arcuate nuclei, MLF, inferior cerebellar peduncle, inferior olivary nuclei

cranial nuclei of medulla

Nucleus ambiguus, spinal trigeminal tract, nucleus solitarious, vestibular nuclei, dorsal motor nucleus of X, CN XII (hypoglossal nucleus?)

what nuclei/tracts have CN IX glossopharyngeal n

Nucleus solitarious, Nucleus ambiguus, spinal trigeminal tract, inferior salivatory

what nuclei have CN X vagus n

dorsal motor nucleus of X, N. solitarious, N. ambiguus, spinal trigeminal tract

Spinal trigeminal tract IX supply

sensation behid ear

Nucleus solitarious IX supply

posterior 1/3 of the tongue

N. ambiguus IX supply

stylopharyngeus - lifts pharynx

inf salivatory nucleus

parotid gland, parasympathetic

Dorsal motor nucleus of X

parasympathetic preganglionic

spinal trigeminal tract CN X supply

ear

N solitarious CN X

epiglottis, taste, cardiorespiratory

N ambiguus CN X

pharynx, larynx

Medial medullary syndrome (Dejerine syndrome/ inf alternating hemiparesis) is caused by occlusion of

vertebral artery/ anterior spinal artery in medulla

Medial medullary syndrome affects which structures

corticospinal tract, medial lemniscus, hypoglossal nucleus nerve

Medial medullary syndrome signs

contralateral hemiplegia, contralateral loss of position and vibratory sense and discriminative touch, deviation of tongue ipsilaterally, muscle atrophy and fasciculation

Lateral medullary syndrome (Wallenburg syndrome or PICA) caused by occlusion of

posterior inferior cerebellar artery - branch of vertebral

Lateral medullary syndrome affects

Inferior cerebellar peduncle, Spinothalamic tract, Descending sympathetic fibers, Nucleus ambiguus, Nucleus Solitarius, Spinal nucleus and tract of Trigeminal

Lateral medullary syndrome signs

Contralateral loss of pain and temperature of body

Ipsilateral loss of pain and temperature of face

Dysphagia, soft palate paralysis, hoarseness, diminished gag reflex

Ipsilateral Horner syndrome

Nausea, diplopia, tendency to fall to ipsilateral side

Ataxia to ipsilateral side