session 2 Flashcards
where does the dorsal column decussate?
at the gracile and cuneate nuclei in the dorsal medulla- it crosses to the medial lemniscus and goes to the cortex
what are the modalities of the dorsal column?
proprioception, vibration, fine touch and pressure
what are the two parts of the dorsal column and what do they do?
-fasciculus gracilis - conveys sensation from lower limbs -fasciculus cuneatus - conveys sensation upper limbs
what 2 places does the dorsal column synapse?
first in the medulla with specific tract nuclei (gracile and cuneate) then in the posteroventral lateral nucleus in the thalamus
where does the spinothalamic decussate?
in the spinal cord 1-2 spinal root levels above where it enters
what are the modalities of the spinothalamic tract?
pain, temperature, crude touch and firm pressure.
where does the spinothalamic tract synpase?
-in the dorsal grey matter horn ( substania gelatinosa) -in the thalamus
what are the 2 parts of the spinothalamic tract and what do they do?
lateral - temperature and pain
anterior - crude touch and firm pressure
what does the corticospinal tract do?
provides conscious motor control of skeletal muscles.
what are the 2 parts of the corticospinal tract and what do they do?
lateral - mainly limb control
anterior - mainly axial muscle
where does the corticospinal tract decussate?
85% of fibres decussate in the medullary pyramids forming the lateral corticospinal tract
15% of fibres remain ipsilateral forming the anterior corticospinal tract but decussate in the anterior white matter of the spinal cord at the level of exit
where do upper and lower motor neurones synapse?
in the ventral horn of the grey matter
in brown-sequard syndrome, what happens below the level of the hemisection?
ipsilateral - loss of fine touch, proprioception and spastic paralysis contralateral - loss of pain, temperature and crude touch
Name all the parts of the vertebra
give 3 differences between cervical and thoracic vertebrae .
- Cervical verterbrae have extra transverse foramina
- C = bifid spinous processes mostly T = long inferiorly projectin processes
- C = triangluar spinal foramen T= smaller circular
- thoracic has costal facets for ribs to articulate on to
what does the ligamentum flavum attach to?
vertebral lamina
what are the movements of the spine?
40 degrees forward felxion
40 degrees rotation
30 degrees lateral flexion
15 degrees extension
where is rotation of the spine at it’s maximum and minimum?
thorax max
lumbar min
what are the 2 most common discs to prolapse?
L5/S1
C6/7
What causes siatica? what are it’s symptoms?
compression or irritation of the siatic nerve (L5 root)
pain radiating down buttock into calf on one side
foot drop - abnormal gait
where does the spinal cord end?
L1 - splits into many roots
Where is a lumbar puncture done and why?
between L3-4
It’s identifiable by the tops of the iliac crest and is lower down than the end of spinal cord so no damage can be done
What is cauda equina syndrome? what are it’s Sx and signs?
compression of spinal roots below the end of the spinal cord (conus medullaris)
lower back pain
saddle parathesia
decreased anal tone
faecal and urine incontience
variable motor loss
sexual dysfunction
what are upper motor neurone damage signs?
extensors weaker than flexors in arms (oppostie for legs) - think stroke arm
no muscle wasting
hyper-reflexia/clonus
spasticity
extensor plantar (babinski)
