Hoorcollege 1 (Erik Scherder) / 10-09-2021
Paresis = partly weakness of your muscles (still able to move)
Na een stroke komt dit relatief vaak voor
Paralysis = complete loss of muscle activity
grote hersen aders: arterior middle en posterior
70% van alle strokes vindt plaats in arterior middle (> mag hemiplegia, meer in arm
en hand dan in been-voet regio) > beide ledematen zijn spastisch (hoge muscle tone
terwijl muscle weakness)!
o Spasticity in de strekkers van het been
o En in de flexie van de arm (daardoor zie je dat de arm gebogen blijft en aan
het lichaam hangt zoals bij Jelle van Gorkom)
Embolia is formed by heart rhytm arithmetia (hartritmestoornis). Hierna afsluiting blood
vessels (infarct), dan volgt oedeemvorming in die regio.
Middle cerebral artery > voorziet groot deel vd hersenen, waaronder een grote sulcus tbv
handfunctie (hierdoor grote armschade). De beenregio is relatief gespaard omdat deze ook
voorziet wordt door de anteriore aders.
Conclusie: arm is meer aangetast in infarct ACM
Conclusie: been is meer aangetast in infarct AAC (anterieur)
Waarom spasticiteit in stroke patient?
ACM is corticaal, maar ook subcorticale vertakkingen. Een daarvan is de a. lenticulostriata
(gaat naar striatum BG striatum > caudate nucleus + putamen)
Q: Are the BG subcortical regions or cortical regions? Subcortical
Q: would you expect problems in BG (subcortical regions) after stroke in ACM? YES
Q: what is spasticity?
A: Spasticity = hypertonia (high muscle tone/hoge spierspanning) of the anti-gravity muscles
Q: why do you see hypertonia after a stroke in the anti-gravity muscles?
A: disinhibition (ontremming of motor activity) > expresses itself as hypertonus of the anti-
gravity muscles (flexion of the arm and extension of the leg)
After stroke you fall back on a lower level of cognition, namely BG. Neocortex is in trouble
and disinhibited. (therefore, exaggeration of eg muscle tone)
Pure hemiparesis: no sensory loss
Q: Where is the lesion in figure 6.14? Is het peripheral or centrally CNS located?
A: CN-7 is a peripheral nerve (not CNS). If the CN itself would be affected then the whole
face will be affected. In the figure, only the lower part of the face is affected.
,The face has a bilateral innervation. The CN-7 is ipsilateral.
CN-7 has bilateral innervation. That’s why the other nerve can help innervate the upper
region. If the upper side is spared, you know that the ‘healthy’ nerve is helping to
innervate the upper part.
If you have a lesion in the cranial nerve nucleus, you would expect the lower part of the face
to be affected as well.
Figuur 6.14 Not the peripheral nerves beschadigd
- Ipsilateral side zou dan beschadigd moeten zijn we zien hier motor laesie aan de
rechterkant vh lijf dus de stroke moet links zijn geweest..
- Unlikely cortical, as lesion would involve entire motor strip; high risk for sensory
involvement (Stroke ACM. What is the chance that only motor areas are affected and
not somatosensory regions? Very small. So the chance of pure hemiparesis caused)
- Not muscle or peripheral: involvement face + entire body half would be required (dan
zouden er heel veel zenuwen tegelijkertijd beschadigd moeten zijn)
- Not medulla + spinal cord: face would be spared
- Unlikely thalamus: somatosensory functions are spared
o Alle zintuiglijke informatie BEHALVE REUK/olfaction via thalamus.
Wat is het dan wel?
- Corticospinal - corticobulbar
- Contralateraal! Want boven de pyramidale decussation
The point where motor systems are crossed over = pyramid decussation / medullary
pyramids (transition between medulla and spinal cord)
Embryological Development of the CNS (learn it!)
- Rhombencephalon (hindbrain): pons, cerebellu, medulla
- Mesencephalon (midbrain): cerebral peduncles, midbrain tectum and tegmentum
o Tectum =
- Prosencephalon (forebrain): telencephalon (cerebral hemispheres/cerebral
cortex+subcortical white matter+BG+basal forebrain nuclei) and diencephalon
(thalamus+hypothalamus+epithalamus)
Lateral Habenula (LHb) projects to VTA (dopamine) and in turn to mPFC (inhibition!)
LDT projects to VTA (dopamine) and in turn to NAcc (reward!)
Anatomical organization: various ways of subdividing the nervous system
- Peripheral vs central
o Central = brain and spinal cord (CNS)
o Peripheral = cranial nerves and ganglia, spinal nerves and dorsal root ganglia,
sympathetic and parasympathetic nerves and ganglia, enteric nervous system
(innerveert maag-darm kanaal) (PNS)
Brachial plexus: nerve brances from outside the spinal cord
- 3 trunks:
, o Superior/upper: C5 and C6 (radial nerve, median nerve)
o Middle: C7 (radial nerve, median nerve)
o Inferior: C8-T1 (radial nerve, ulnar nerve, median nerve)
Ask patients to make a fist with their hands verschillende uitingsvormen
Neuropathic gait (filmpje): CNS or PNS
- …
Stuk gemist ivm lokaal wisseling
Als je herstel verwacht van arm-handfunctie, wat verwacht je dan eerder te zijn hersteld? (1)
handfunctie, (2) armfunctie. A: armfunctie
Vanwege disinhibitie rechterhemisfeer, onmogelijk om de flexie van de elleboog te counter-
forcen dus strekken is niet mogelijk
Herewith some comments. The lecture was primarily meant as a warming up. So a few basics:
the long motor descending pathways (corticospinal tract, pyramidal tract) crossover at the
pyramidal decussation at the medullary-spinal level. In other words, the corticospinal tract in right
hemisphere controls the motor activity of the left side of the body, and visa versa. More detailed
information about the corticospinal tract will follow later. Three major cerebral arteries include:
anterior cerebral artery, middle cerebral artery and the posterior cerebral artery. The middle
cerebral artery is affected in 70% of the patients with a stroke. A stroke may include an infarction,
by an occlusion of a vessel due to an embolia, or a hemorrhage, bleeding, by a rupture of a blood
vessel. An infarction concerns a more localized area whereas a hemorrhage may cause more
diffuse damage since the blood may spread over the brain, in the sulci. An extra pressure on the
brain parenchym emerges from edema. An infarction by an occlusion of the middle cerebral
artery (MCA) expresses itself in a characteristic clinical outcome: the arm/hand is more affected
than the leg. Do you remember why the leg is relatively less affected? The damage to the cortex
(and subcortex) causes a disinhibition of the motor system, contralateral the lesion, which is
reflected in hypertonia, or otherwise, spasticity. The hypertonia holds for the extensors of the leg
and the flexors of the arm, both at one side of the body: hemiplegia, hemiparesis, hemi-paralysis.
The opposite of spasticity is flaccidity (slapte), a condition that you may find in the acute phase
after the stroke but particularly in patients with a lesion of the peripheral nervous system. Another
characteristic of a lesion of the peripheral nervous system is atrophy: the size of the muscle
reduces. One of the subcortical branches of the middle cerebral artery is the lenticulostriate
artery, supplying the basal ganglia. This means that in a stroke patient both cortical ánd
subcortical areas could be affected. Clearly, the clinical outcome differs if the lesion is purely
cortical or cortical-subcortical.
