Ascending and Descending Spinal Tracts Flashcards by Alanis Delgado

Site of origin of lateral corticospinal tract

Primary motor cortex 4, 6 - pyramidal cells

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Site of decussation of lateral corticospinal tract

Pyramidal decussation at cervicomedullary junction

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Where does the lateral corticospinal tract terminate

Ventral horn motor neurons / entire cord - mostly enlargments of c & l

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Function of lateral corticospinal tract

Movement of contralateral limbs, particularly digits

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Site of origin of rubrospinal tract

Red nucleus of midbrain tegmentum

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Site of decussation of rubrospinal tract

Ventral tegmental decussation in midbrain (tectum)

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Where does the rubrospinal tract terminate

Ventral horn of Cervical cord

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Function of rubrospinal tract

Movement of contralateral limbs - flexors

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Site of origin of anterior corticospinal tract

Primary motor cortex

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Site of decussation of anterior corticospinal tract

Does not decussate

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Where does the anterior cortispinal tract terminate

Ventral horn motor neurons / Cervical and thoracic cord

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Function of anterior corticospinal tract

Control of axial muscles

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Site of origin of medial vestibulospinal tract

Medial and inferior vestibular nuclei

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Site of decussation of medial vestibulospinal tract

Does not decussate

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Where does the vestibulospinal tract terminate

Interneurons at Cervical and thoracic cord

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Function of the medial vestibulospinal tract

Positioning of head and neck posture

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Site of origin of lateral VST

Lateral vestibular nuclei

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Site of decussation of lateral VST

Does not decussate

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Where does the lateral VST terminate

Interneurons at ventral horn Entire cord

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Function of the lateral VST

Balance and posture of extensor muscles

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Site of origin of reticulospinal tract

Medial -Pontine nucleus and
Lateral or medullary - gigantocellular nucleus in medullary reticular formation

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Site of decussation of reticulospinal tract

Does not decussate, have their own medial and lateral reticulospinal tracts

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Where does the reticulospinal tract terminate

Interneurons and motor neurons of Entire cord

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Function of reticulospinal tract

Posture and voluntary movement reflex activity
Pontine - extensor
Medullary - flexor

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Site of origin of tectospinal tract

Superior colliculus of midbrain

Site of decussation of tectospinal tract

Dorsal tegmental decussation in midbrain soon after origin (tectum)

Where does the tectospinal tract terminate

Interneurons of Upper Cervical cord ^^

Function of the tectospinal tract

Coordination of head and eye movements

Weakness of one side of body

Paresis

No movement of one side of body

Plegia

No movement of legs

Paralysis

Weakness or paralysis of face muscles

Palsy

Where does the corticospinal tract travel through until decussation

corona radiata - internal capsule - basis pedunculi - transverse pontocerebellar fibers - pyramid

Corticospinal deficits

Clasp-knife spasticity Babinski's sign Hemiparesis weakness Hyperreflexia

Corticospinal lesions above decussation

Contralateral deficits

Corticospinal lesions below decussation

Ipsilateral deficits

Midbrain lesion at corticospinal tract deficits

1. contralateral hemiparesis weakness 2. deviation of ipsilateral eye down and lateral

Why does the midbrain affect eye down and lateral

branches of posterior cerebral artery supplying oculomotor nerve to elevate and adduct eye

Pons lesion at corticospinal tract deficits

1. contralateral hemiparesis 2. deviation of the eye inward

Why does the pons affect eye inward

branches of basilar artery affect abducens nerve the innervated lateral rectus muscles which abducts eye

Medulla lesion at cortispinal tract deficits

1. contralateral hemiparesis 2. ipsilateral flaccid paralysis of tongue deviation towards lesion

Why does the medulla affect tongue

branches of anterior spinal artery affect hypoglossal nucleus innervating muscle of tongue movement

Where does the rubrospinal tract descends through

lateral funniculus

Where does the medial VST descend through

medial longitudinal fasciculus MLF

Where does the lateral VST descend through

ventral funiculus

Function of Dorsal column medial lemniscus pathway

Discrimiative touch, vibration, proprioception

1st order neuron of DCML

DRG (Ia, Ib, II) fasciculi gracilis and cuneatus

2nd order neuron of DCML

nuclei gracilis and cuneatus at medulla

3rd order neuron of DCML

ventral posterolateral nucleus of thalamus (VPL)

How do you test for conscious proprioception

field sobriety test

Where does the DCML decussate

2nd order neurons decussate at IAF internal arcuate fibers

Deficits due to lesions in the DCML

loss of sense of touch, vibration and proprioception

Lesions above IAF decussation

Deficits are below on opposite side

Lesions below IAF

Deficits are below and on same side of lesion

1st order neurons of Anterolateral pathway

DRG via tract of Lissauer and synapse with Proper sensory Nucleus

2nd order neurons of anterolateral pathway

dorsal horn cross to ventral white commisure

where does the anterolateral pathway decussate

anterior white commisure to ventrolateral column

where does the anterolateral pathway ascend through

contralateral VPL to thalamus

3rd order neurons of anterolateral pathway

VPL goes through posterior limb of internal capsule to corona radiata

Deficits to anterolateral pathway

Loss of pain and temperature sensation on contralateral side of the body beginning one to two levels below the lesion

white commisure is damaged

syringomelia

1st order neurons of dorsal spinocerebellar

DRG T1-S3

2nd order neurons of dorsal spinocerebellar

nucleus dorsalis of Clarke's T1-L3

where does the dorsal spincerebellar tract enter

inferior cerebellar peduncle

function of dorsal cerebellar

trunk and lower limbs proprioception

1st order neurons of ventral spinocerebellar

DRG T1-S3

2nd order neurons of ventral spinocerebellar

nucleus dorsalis

where does decussation take place in ventral spinocerebellar

1. at 2nd order neuron dorsal to ventral spinocerebellar tract 2. cross back behind cerebellum

function of ventral cerebellar

lower limb proprioception

1st order neurons of cuneocerebellar

DRG C2-T7

2nd order neurons from cuneocerebellar

accesory cuneate nucleus

where do cuneocerebellar axons travel through

fasciculus cuneatus

where do 2nd order neurons cuneocerebellar tract enter cerebellum

inferior cerebellar peduncle

function of cuneocerebellar

upper limb and trunk proprioception

deficits of lesions to cerebellar pathways

dystaxia or ataxia - coordination difficulty

dorsal spinocerebellar damage

ipsilateral leg dystaxia

ventral spinocerebellar damage

contralateral leg dystaxia

cuneocerebella damage

ipsilateral arm dystaxia

Ascending and Descending Spinal Tracts Flashcards

(78 cards)