Ascending And Descending Tracts Of Spinal Cord Flashcards
Where only can you find the lateral horn?
Thoracic region
What is in the lateral horn?
Preganglionic sympathetic neurons
Which type of movement passes through dorsal medial meniscus?
Fine touch vibration
Proprioception
1st order neurons- dcml?
Enter dorsal column same side within the fasciculata gracilis cuneatus
Fibres ascend uncrossed
Synapse on medulla
What information does fasciculus cuneatus have?
Upper limb
Dcml 2 neurons?
Cross in medulla and ascend to thalamus
Forming medial lemniscus
Then project from thalamus to somatosensory cortex
Damage to dorsal column- lesion on one side of spinal cord?
E.g multiple sclerosis
Loss of tactile and proprioception on same side
Symptoms such as sensory ataxia- loss of coordination
Clinical test for damage to dorsal column?
Romberg’ sign- severe swaying on standing with eyes closed feet together
Spinothalamic tract is for?
Pain
Temperature
And course touch
1st order neuron of spinothalamic?
Enter dorsal horm and form tract of lissauer.
Collateral branches given off at tip of dorsal horn, run up or down 1-2 spinal segments
Synapse in dorsal horn with second
Spinothalamic second?
Cross in dorsal horn at each level
Ascend in aterolateral column to thalamus
Fibres from lower limb- lateral
Fibres from upper limb- medial
Then project from thalamus to somatosensory cortex
Damage to anterolateral column?
Lesion on one side will result in loss of pain temp and course touch of opposite side
Outer tract injury such as cord compression due to herniated disc?
Loss of lower limb pain
Inner tract injury i.e grey matter tumour can result in?
Loss of upper limb pain
Unconscious muscle proprioception is done by?
Spinocerebellar tracts for smooth motor coordination
Which are the spinocerebellar tracts for trunk and lower limb?
Ventral and dorsal
Which are the spinocerebellar tracts for upper limb?
Rostrum and cuneocerebellar
Spinocerebellar tracts terminate in cerebellum at?
Same side
Spinocerebellar tracts first order neurons?
Synapse in dorsal horn
Then ascend the lateral column to cerebellum, very fast axons
Lesion on one side of spinal cord for dorsal spinocerebellar will result in?
Uncoordinated lower limb muscular activity on same side
Pyramidal tract have 2 neurons?
Upper motor- from cerebral cortex to ventral horn
Lower motor- ventral horn to skeletal muscle
Upper motor neuron journey?
Primary motor cortex to internal capsule to cerebral peduncle to pons to pyramid of medulla to lateral/anterior corticospinal tract
Corticospinal tract fibres decimate at medulla so?
80% cross midline to form lateral
20% on same side - anterior corticospinal
Lower motor organisation in ventral horn?
Medial -trunk
Anterolateral- proximal limb
Posterolateral - distal limb
What causes motor neuron disease?
Disruption of corticospinal tract
Upper motor neuron disease causes?
Spastic paralysis (increased muscle tone)
Overactive tendon reflexes
No signicant muscle atrophy
E,g following stoke
If the upper motor neuron injury is above pyramids?
Then on opposite side
If below pyramids then same side
If lower motor neuron injury in ventral horn or periphery then?
Flaccid paralysis
No tendon reflexes
Muscle atrophy
E.g spinal muscular atrophy
Guilin barre syndrome
Amyotrophic lateral sclerosis?
Affects lower and upper motor neurons
Progressive muscle weakness and atrophy but mind intact
Symptoms in limbs or bulbar signs
Short life span for 5 days
How many people affected by amyotrophic lateral sclerosis?
4-5 per 100,000
Which are the extra pyramidal tracts?
Rubrospinal- red nucleus midbrain
Reticulospinal- reticular formation-pons
Vestibulospinal- vestibular nuclei in medulla
Why are extrapyramidal tracts needed?
Maintaining posture and regulating involuntary movements
Lesions to extrapyramidal tract cause?
Movement disorders ie. dyskinesia- involuntary muscle movement
Dystonia- involuntary muscle contractions
