Spinal Cord and Injury Flashcards
(52 cards)
Describe the gross anatomical make up of the spinal cord
H-Shaped grey matter - dorsal, intermediate and ventral horns
Surrounding white matter - Dorsal, lateral and ventral funiculi
Describe the make up of the meningeal layers
Dura Mater Arachnoid Mater (Sub arachnoid space) Pia Mater (Subpial space - spinal cord, very tiny)
Where does the dura mater fuse with endosteum of cranium?
Foramen magnum
What separates the dura mater from vertebrae in spinal cord?
epidural space
Where within the meningeal layers is CSF found?
Subarachnoid space
Where is CSF made?
Choroid plexus of ventricular system
What laterally forms from the pia mater?
21 dendriculate ligaments - stabilise spinal cord
What spinal vasculature is important for the mestastasis of lower abdomen tumours?
Bastons Venous Plexus
Describe the arterial supply of gthe spinal cord
Aorta - intercostal arteries - single anterior and 2 posterior spinal arteries
What is the artery of adamkiewicz and what is its clinical significance regarding surgery?
Arises from left posterior intercostal artery to supply lower third of spinal cord.
Can become occluded following surgical procedures
Where does the supracristal line lie and what is its functional importance?
through body of L4 - landmark for epidural and spinal tap
Which route through the spinal cord so sensory pathways take?
Dorsal
Which route through the spinal cord so Motor pathways take?
Ventral
Descending - Ds dont go together - descending and dorsal
List and describe the functions of the different sensory axons:
A-alpha - proprioceptors of skeltal muscle. Thick and fast
A-beta - mechanoreceptors of skin - medium thickness and fairly quick
A-Delta - Pain and temperature receptors. thin and slow
C - polymodal - thinnest and slowest
Name and describe the pathway responsible for discriminative touch
Dorsal column/Medial lemniscus pathway:
- primary neuron enters dorsal column and travels up to medulla where is synapses at gracile nucleus with internal arcuate fibres - These decussate and pass through medial lemniscus of vertebrae to the VPL of thalamus - synapses here to pass through internal capsule and onto sensory cortex
Where does the medical lemniscus pathway decussate?
Dorsal column nuclei (Gracile nucleus) in medulla
Where does the spinothalamic pathway decussate?
At level of entry
Name and describe the pathway responsible for pain
Spinothalamic pathway:
- Primary afferent neuron enters superficial dorsal horn via spinothalamic pathway, using A-delta or C fibres - Synapses otno second order neuron and decussates at level of entry - Travels up thoracic and cervical white matter in antero-lateral funiculus, through spinothalamic tract and through spinal lemniscus in brainstem - synapses onto 3rd order neuron at internal capsule to target sensory cortex
What are the two ascending sensory pathways?
Medial lemnisus and spinothalamic
Which of the descending motor pathways are responsible for voluntary movement?
Corticospinal tract - movement of torso, arms and legs
Corticobulbar tract - non oculomotor cranial nerve movements
Name and describe the pathway responsible for arm/leg/torso movement
Lateral Corticospinal tract (85%):
- axons leave primary motor cortex to medulla where they decussate. - travel down lateral corticospinal tract to synapse with spinal nerves
Anterior corticospinal tract (15%):
- axons leave primary motor cortex and travel straight down spinal cord in anterior corticospinal tract - Decussate to synapse with spinal nerves at level of exit
Name and describe the pathway responsible for movement controlled by cranial nerves
Corticobulbar tract:
- axons from primary motor cortex pass through cerebral peduncle of midbrain and to the corresponding cranial nerves in pons (facial) or medulla (hypoglossal) where they decussate
What is the difference in the decussation of the lateral and anterior corticospinal tracts?
Lateral - medulla
Anterior - at exit point of spinal nerves
Name and describe the pathways responsible for maintaining posture (muscular tone)
Reticulospinal - made up of pontine (extensor) and medullary (flexor) tracts to modulate alpha motor neurones
Tectospinal - only prejects to cervical segments, modulating alpha and gamma motor neurons
Vestibulospinal -runs entire length of cord, modulating activity of alpha motor neruons
