Week 1 Control Q&A copy 2utf Flashcards
What is the palpebral fissure?
Palpebral fissure (area between 2 eyelids
Which eyelid is bigger and more mobile?
upper
What are the canthus? How many?
commissures: medial and lateral
What is the lacrimal caruncle?
red bit
what is the lacrimal papilla?
the bit close to medial canthus with punctum (hole): upper and lower lids
how do tears enter the lacriaml sac?
via the punctum (holes) into superior and inferior lacrimal canals
what is the sclera
white bit of eye
where is the canal of schlemm
sclero-corneal jct (limbus)
what part of the eye is avascula
cornea
a small bit of sclera is usually visible above or below iris?
below
what is the fibrous tunic?
outer layer of eye: sclera and cornea; cts with dural covering of optic nerve
where is the optic nerve on the retina?
medial (more nasal than the fovea is)
what is the lamina cribosa? What does it do?
where sclera is perforated by emerging nerve fibres. is a mesh-like structure that allows optic nerve to pass through sclera. It helps to maintain pressure inside vs outside the eye.
wht is the vascular tunic?
choroid, ciliary body, iris
what does the choroid do?
absorb excess light, so not reflected within eye ball
what is the macula and fovea? Where?
The macula is important for high-acuity, central vision. More lateral than optic disc. No bipolar/ganglion cells here, so light gets directly to photoreceptors.
what is the blind spot
optic disc (optic nerve head)
other than the nerve, what comes out of the optic disc?
cenral retinal artery and vein, which branch in quadrants
what happens with central retinal artery occlusion
unilateral vision loss. Painless
how much refraction is done by cornea?
two thirds
what is the hyaloid fossa?
the depression of the vitreous where the lens sits of the vitreous body
what are zonule fibres?
make up suspensory ligament. Tension in the zonule fibres flattens the anterior surface of the lens. Contraction of the ciliary muscle increases the refractive power of the lens because it makes suspensory ligaments floppy and the lens more fat (greater optic power of lens).
anterior and posterior segments vs chambers of the eye?
segments are the large bits, separated by lens, and the anterior segment has anterior and posterior chambers, separated by the iris.
how does aqueous humor flow?
Aqueous humour flows from capillaries in ciliary process of cilliary body, out behind iris, through pupil, in front of iris, through trabecular meshwork, to the sinus venosus sclera (or canal of Schlemm).
which muscle does not attach to the tendinous ring? Where instead?
inferior oblique: nasal orbital bone (floor of)
what is the visual pathway?
Optic nerve ˆ chiasm ˆ optic tract ˆ LGN (thalamus) ˆ optic radiations ˆ primary visual cortex
which sulcus in occipital lobe contains visual cortex?
calcarine
where is the fovea represented in the occipital lobe
pole
what is hemianopia
loss of half visual field
What is the significance of PITS?
inferior visual field processed above calcarine fissure (parietal), superior visual field processed below calcarine fissure (temporal)
Why might a loss of sympathetic innervation cause mild drooping (ptosis) of the eyelid?
Ê loss of SYM innervation of the superior tarsal muscle eg HornerÕs
Why might more of the sclera be visible in anxiety states or hyperthyroidism?
a.ÊÊÊÊ Due to SYM innervation that raises the eyelid (anxiety) due to proptosis (eye popping forwards) in hyperthyroidism.
Would selective disease of the rods or cones be most likely to affect night vision?
rods
What is myopia and what does it have to do with the antero-posterior length of the eye?
a.ÊÊÊÊ Short sightedness. Due to long eyeball, so that rays of light converge before the lens.
What is the normal intraocular pressure and upper limit of normal?
10-21 mmHg
What anatomical changes occur in glaucoma (seen clinically, by fundoscopy)?
a.ÊÊÊÊ Increased cup:disc ratio (>0.4), paler disc due to atrophy of the neural tissue
What are the clinical features of a complete third nerve palsy?
a.ÊÊÊÊ Eye is down and out (due to actions of the trochlear and abducens, which are still working when the oculomotor nerve is not working). Also complete ptosis (70%).
In 3rd nerve palsy: is the puil dilated or constricted?
dilated
If a patient has hemianopia, is the lesion anterior or posterior to the optic chiasm?
a.ÊÊÊÊ After. If before, you would just lose an entire eye
Why might Goliath not have seen David and his slingshot? (Clue: growth hormone)
Acromegaly _ tumour of pituitary, so have bitemporal hemianopia.
Discuss the anatomical basis of the pupillary light and accommodation reflexes.
Light: afferent information from a single eye, to midbrain, efferent information returns to both eyes. Cross at edinger-westphal nucleus. PARA CN3. Accommodation/Near reflex: small pupil, accommodation of lens (bulge), convergence of eyes on nose. PARA.
What are the meninges?
coverings of barin: dura - arachnoid - pia
Speak about the attachments of the meninges
The dura is tightly adherent to the periosteum lining the skull. Hence, the dura is usually left behind when the brain is removed from the skull. The arachnoid is only loosely attached to the dura and remains with the brain. So usually the membranes you can see on the brain are the arachnoid and pia. Pia covers every gyrus and sulcus like a layer of Ôshrink wrappingÕ.
Where is CSF?
ventricles, central canal, sub-arachnoid space
what are the arachnoid trabeculae?
delicate strands connective tissue- extend between the arachnoid and pia. They suspend the brain like puppet strings as it ÔfloatsÕ in a layer of CSF.
Where are the major blood vessels located within the brain?
Blood vessels within the subarachnoid space. Arachnoid is transparent so you can see vessels in the subarachoid space. Leak or trauma (more likely aneurism than trauma) = haemorrhage.
what are the 3 major divisions of the brain?
cerebrum, cerebellum, brainstem
what is the crack between the 2 hemispheres?
longitudinal fissure with falx cerebri (dura).
how do the dura reduce movement of brain in skull?
falx cerebri: reduces side-to-side movement of brain. Tentorium cerebelli: limits superior-inferior movements of the brain within the skull.
what is the corpus callosum
a major bundle of white matter linking the two hemispheres.
what is the crack between Cb and cerebrum?
transverse fissure
what is the tentorium cerebelli?
dural fold - forms a roof over the posterior cranial fossa
what is the hole in the dura for the brain stem
tentorial hiatus
in which direction is there no dura to stop brain movement?
anterior-posterior
where is the vermis?
midline of cerebellum; 2 Cb hemis on eitehr side
what is the arbor vitae?
inside the Cb: tree-like, branching pattern of the white matter
does the cerebellum have gyri and sulci?
Cb has folia and fissures (cf. gyri and sulci in the cerebrum), which oriented transversely.
where are the tonsils? Clinical signifiance?
posterior Cb. Lobules of Cb. presses on the medulla during high intracranial pressure and causes death (presses on respiratory and cardiac centres of medulla).
which embryological structure do the brain/spinal cord develop from?
neural tube
what is CSF produced by
choroid plexus in each ventricle
how does CSF flow?
2x lateral (with frontal, occipital and temporal horns) separated by septum pellucidum ˆ interventricular foramen (Y shaped from front) ˆ 3rd ventricle (2 thalamus connected through hole) ˆ cerebral aqueduct ˆ 4th ventricle (between brain stem and Cb)ˆ 2x medial foramen of majendie, 2x lateral foramen ˆ Sub-arachnoid space ˆ arachnoid villi/granulations to reabsorb into dural sinuses and back into bloodstream
In which view do the ventricles look like a Y shape?
coronal
which CNs are PARA
3,7,9,10
what is ptosis vs proptosis?
Ptosis (droopy eyelid) vs proptosis (pop out eye)
what are the internal and external parts of the oculomotor nerve specialised for?
internal: motor; external: PARA. Suregery/ICP damages outer first. Ischemia damages internal first
Why do ruptured brain aneurysms cause bleeding into the subarachnoid space?
a.ÊÊÊÊ Because vessels located here. Not usually trauma of these vessels (because protected a bit), so usually haemorrhage due to aneurysm (ballooning of vessel wall, which is weak and can rupture
What happens to the subarachnoid space in places where the skull bone is at a distance from the surface of the brain (e.g. between medulla and cerebellum)?
Lots CSF there
Why is this useful if a CSF sample is needed but a lumbar puncture cannot be done?
a.ÊÊÊÊ Can sample CSF here
How might the arrangement of the dural partitions make the anterior and posterior poles of the brain more susceptible to damage in traumatic head injury?
a.ÊÊÊÊ Anterior-posterior movement of brain within skull
A stroke in the left cerebral hemisphere might cause weakness on which side of the body?
right
A stroke in the left cerebellar hemisphere might cause ataxia (inco-ordination) on which side of the body?
left
In advanced raised intracranial pressure the tonsils may herniate through the foramen magnum and cause death by compressing which part of the brain stem?
medulla (resp centre)
What happens to the ventricular system if there is a focal obstruction?
hydrocephalus
Symptoms of hydrocephalus and how to treat?
a.ÊÊÊÊ Child: enlarged head, bulging fontanelle; Adult: headache, vomit, nausea, seizure; Shunt to bypass obstruction and allow flow of CSF
what part of the brain stem has pyramids?
medulla
what part of the brain stem has olives? Where are olives located?
medulla. Olives = oval swellings just above and lateral to the pyramids on each side (upper medulla).
what is the meaning of the pons?
bridge; bridges two Cb hemis
what is the importance of the ventral median fissure of the medulla?
contains basilar artery
Where are the peduncles of the midbrain?
Above the pons = the two cerebral peduncles of the midbrain, which resemble two Roman pillars, separated by a gap. The gap is the interpeduncular fossa (Latin: ditch
in which fossa is the oculomotor nerve? Where does it emerge
interpeduncular fossa. Emerges between the cerebral peduncles.
what is the tectum?
tectum is the posterior area of the midbrain (Latin: tectum, roof). There are four elevations (2x superior and inferior colliculi) of the tectum.
what is the importance of the superior and inferior collicular?
visual (superior) and auditory (inferior) reflexes. Eyes above ears, so superior is about vision and inferior about audition. The superior colliculus is not part of the main visual pathway, but the inferior colliculus is part of the main auditory pathway.
where is the origin of the trochlear?
below the inferior colliculi
Where does the abducens nerve emerge?
emerges between the pons and the medullary pyramid. It emerges in the same vertical line as the oculomotor nerve
which nerve is V shaped? Where is the V located?
trigeminal, mid pons
what are the 3 branches of the trigeminal nerve?
áÊÊÊÊÊÊ Trigeminal has three branches (V1, V2, V3) supplying sensation to the face. Opthalic (orbital), maxillary (rotundum), mandibular (ovale)
Explain how CNs 6, 7, 8 emerge
áÊÊÊÊÊÊ CN6, 7 and 8 emerge at the junction of the pons and medulla. They emerge in sequence from medial to lateral: CN VI (abducens), VII (facial) and VIII (vestibulo-cochlear).
what does the facial nerve supply?
áÊÊÊÊÊÊ The facial nerve is a motor nerve supplying muscles of facial expression, also anterior 2/3 tongue.
where do CNs 9-11 emerge? What do they supply?
áÊÊÊÊÊÊ Cranial nerves 9, 10 and 11, emerge from behind the olive. These nerves give sensory and motor supply to the pharynx and larynx.
where does CN12 emerge? Supplies?
áÊÊÊÊÊÊ The hypoglossal nerve (XII), emerges in front of the olive. Supplies intrinsic tongue muscles.
Exit foramina of: olfactory nerve?
cribiform plate of ethmoid bone
Exit foramina of: optic nerve
optic canal (sphenoid bone)
Exit foramina of: opthalmic nerve?
SOF
Exit foramina of: V1, V2, V3
SOF; rotundum; ovale
Exit foramina of: middle meningeal artery?
spinosum
Exit foramina of: CN7 and 8
internal auditory meatus
Exit foramina of: CN12
hypoglossal canal
Exit foramina of: CN 9, 10, 11
jugular foramen (find by following dural sinus down)
What is in the superior orbital fissure?
live frankly to see absolutely no insult = lacrimal, frontal, trochlear, superior oculomotor, abducens, nasociliary, inferior oculomotor
Which clinically important tract descends in the pyramids of the medulla?
a.ÊÊÊÊ Corticospinal (concerned with movement). Also corticobulbar a bit (more in pons).
What would be the clinical effect of transecting the left pyramid?
a.ÊÊÊÊ Right hemiplegia (paralysis). No facial signs because corticobulbar is mostly in pons.
Why is the superior oblique sometimes called the trampÕs muscle?
a.ÊÊÊÊ Down and out movement of eye (also intortion)
Diplopia on far lateral gaze could be caused by weakness of either of which two muscles?
a.ÊÊÊÊ Double vision. Due to lateral rectus mostly and also medial rectus CHECK
Why might someone with facial weakness also have changes in their sense of taste?
a.ÊÊÊÊ Facial nerve supplies anterior 2/3 tongue
What is trigeminal neuralgia?
a.ÊÊÊÊ Severe v v bad facial pain. Comes and goes in attacks.
Describe the clinical features of a left hypoglossal nerve lesion.
a.ÊÊÊÊ Tongue towards affected side (unopposed genioglossus muscle)
Would the sense of taste be affected by a lesion of the hypoglossal nerve root?
a.ÊÊÊÊ CHECK No, because anterior 2/3 is facial and posterior 1/3 is glossopharyngeal
Is the optic ÔnerveÕ actually a tract? (Why/why not?)
a.ÊÊÊÊ A nerve is officially PNS, but the optic nerve is between two parts of CNS, so perhaps would be best called a tract (within CNS)
A lesion in which branch of the trigeminal nerve might also cause jaw weakness?
V3 (mandibular)
where is grey vs white in brain vs spinal cord
brain, white matter is deep = myelinated axons (opposite in spinal cord)
where is grey matter in the brain
crortex and deep, subcortical structures
what are grey bundles called in CNS vs PNS?
CNS: nuclie; PNS: ganglia
where is the thalamus? Does it cross?
quailÕs egg shaped, close to the midline (the largest of all CNS nuclei). This is the GATEWAY to the to the cerebral cortex for ascending pathways. ÔKissÕ across third ventricle in most ppl.
where is the basal ganglia
lateral to thalamus
What are the functions of the basal ganglia?
motor initiation of voluntary movement (Parkinsons); also cognition (motivation, reward)
what is the internal capsule? Sections?
white matter tract that passes through the deep nuclei. The sensory and motor tracts pass through here to get between thalamus and cortex. Anterior, genu and posterior (dog’s leg) sections in axial slices
What is the pathway for the corticospinal tract?
CC ˆ corona radiatia ˆ posterior limb of internal capsule ˆ crus cerebri (midbrain) ˆ pyramid (medulla) ˆ decussate ˆ spinal cord. NB motor does NOT stop in thalamus
where are UMN cell bodies?
primay motor cortex
what has: peduncles and interpeduncular fossa?
midbrain
what has tectum
midbrain (roof)
where is the tegmentum
Midbrain; in front of cerebral aqueduct: Tectum (Latin: roof) dorsal to (behind) the cerebral aqueduct cf Tegmentum (in front of cerebral aqueduct).
which part of the brainstem do you not see easily on a whle brain
midbrain (it is deep)
where is substantia nigra?
midbrain (Da)
what are the crus cerebri?
white matter tract in mibrain; immediately anterior to substantia nigra
if you have anterior midbrain stroke, what clinical features?
can also get ipsilateral third nerve (oculomotor) palsy. This is because the cranial nerves are peripheral nerves, and they do not decussate. CN3 is in the midbrain, so if it gets damaged then you will have ipsilateral damage.
compare which parts of face supplied by trigeminal branches
V1 (ophthalmic) goes to tip of nose, V2 gives nostrils.
where is the corticospinal tract in the brainstem?
pyramids of medulla
What do the corticospinal vs corticobulbar supply?
Corticospinal: goes to the spinal cord and supplies motor in body. Corticobulbar: peels off in brain stem to supply motor face and neck.
Where is the LMN cell body?
cell body in anterior horn (grey matter) of spinal cord
Why are LMNs called the ‘final common pathway’?
because voluntary motor commands from cerebral cortex, and involuntary reflexes use this pathway.
Explain normal muscle tone through the stretch reflex
Normal muscle tone is based on the stretch reflex: muscle spindle gets stretched, this sends a sensory signal via dorsal root to spinal cord about the stretch. There is a mono-synaptic connection with a lower motor neuron, signal goes out through ventral root to contract the muscle (NMJ, Ach). Also get connection with an inhibitory interneuron in the spinal cord, so the antagonistic muscles get told to relax. This is how you get normal muscle tone
what is hypotonia due to
LMN damage
what is hypertonia due to?
UMN damage (no dampening down of reflex from brain). UMN damage - everything goes UP
Could a small (
Yes. The posterior limb of internal capsule contains both sensory and motor tracts. Even
Tremor and muscular rigidity suggests a disorder of which part of the brain?
Basal ganglia _ substantial nigra in midbrain
What are the clinical features of an upper motor neuron lesion?
áÊÊÊÊÊÊÊ Hyperreflexia, hypertonia, clasp knife, spasticity, BabinskiÕs sign (toes flare up). In UMN lesion, everything goes UP.
If you are looking at an MRI scan in the coronal plane and it includes the thalamus, is the section passing through the anterior or posterior limb of the internal capsule?
áÊÊÊÊÊÊ Posterior. If you were taking coronal slices, you would first go through anterior limb of internal capsule, then genu, and when you got to thalamus, youÕd be at the posterior limb.
If a patient has facial weakness on the left but arm and leg weakness on the right, then where must the lesion be located? [options: hemisphere, brain stem, spinal cord]
Left brainstem
In general terms, cranial nerve signs on one side combined with long-tract signs on the other side suggests a lesion in which part of the CNS? [assuming there is only one lesion]
Brainstem. The cranial nerves originate from the brainstem and innervate the ipsilateral face (this is because cranial nerves are peripheral nerves).
What is this neurological pattern called?
crossing over / alternating
Does arreflexia (absence of tendon reflexes) imply an upper or lower motor neuron lesion?
LMN
In what condition are both upper AND lower motor neuron signs commonly seen?
Motor neuron disease (also, it is a LATE/progressive sign of MS, but not acute)
how can you tell that a vertebra is cervical?
transverse foramen and bifid spinous process
which transverse foramen carry vertebral arteries
C1-C6
where is there more white matter in spinal cord: top or bottom? Why?
there is more white matter towards the TOP of the cord because you add more sensory ascending tracts as you go up and lose motor descending tracts as you go down
what are facet joints called on vertebra? Type of joint?
Zygapophyseal (ÔfacetÕ) joints: smooth, concave surface. Plane synovial.
where is CSF in spinal cord
central canal, plus Subarachnoid space between arachnoid and pia is continuous with the CSF-filled space that surrounds the brain.
what is in the extra-dural space of spinal cord?
The extradural (epidural) space which contains fatty connective tissue. The internal vertebral venous plexus is within the extradural space.
are spinal nerves sensory, motor or mixed
mixed
there is a ganglia on ventral or dorsal root? What does it contain?
Dorsal root ganglia on posterior/dorsal root (first order sensory neuron cell bodies).
Explain the shape of the spinal cord
Cord: H-shaped central grey matter and central canal. Wide ventral median fissure and the narrow dorsal median sulcus. Dorsal (sensory) and ventral (motor) horns.
what is contained in the dorsal horn?
second-order spinothalamic tract sensory neurons.
where do spinothalamis axons cross the midline of the spinal cord?
ventral (anterior) white commissure
what is in the anterior horn of spinal cord?
cell bodies of LMN
where are intermediolateral horns?
only at the level of the SYM system, as they contain pre-ganglionic cell bodies (motor, descending): T1-L1/L2
where are the enlargements of the spinal cord?
cervical and lumbar for upper and lower limbs
what is the conus medularis?
termination of spinal cord, tapers here
what is the filum terminale?
fibrous tissue, connects spinal cord to sacrum
in what direction do spinal nerves exit from the cord (horizontal, verticle)?
cervical: almost horizontal; lower spinal neves are more oblique and cauda equina is almost verticle
where is the SYM chain? What does it contain?
SYM chain (knots on string) is anterior to the transverse process. This contains post-ganglionic cell bodies. Preganglionic cell bodies are in the lateral horn (pseudo uni polar).
what are communicating rami?
Communicating ramus (Ôramus communicansÕ) come off the spinal nerve. White ramus is myelinated and grey is not. White is more lateral (in front?).
Where are white vs grey rami?
White rami are only found at T1-L2/L3 (where the SYM chain is), but grey rami are present at all levels. This is because grey has to go IN to all levels, but white only comes OUT at the levels of SYM
what are the 3 cervical SYM ganglia?
Three cervical sympathetic ganglia (superior, middle and stellate). SYM supply to the head is distributed by the carotid artery.
the SYM nerves can do what, once entering the SYM ganglia white white rami?
up or down the SYM chain, back out through grey rami at same level, or straight through to splanchnic
What happens if nerve goes straight through the SYM ganglia?
Can go straight through to splanchnic nerve and to the 4 pre-vertebral ganglia in front of the aorta: celiac, superior and inferior mesenteric, aortic/renal
why is the adrenal medulla like a special post-ganglionic cell body group?
It is directly innervated by preganglionic SYM fibres, and releases NA and Adrenaline
What is the pain gate?
pain through spinothalamic tract and touch through dorsal column. The dorsal column gets priority and hence pain reduced when you rub injury. This is why we use tiger balm: rub and the different sensations from tiger balm reduce the pain sensation.
what are the 3 main groups of thalamus and how are they split?
split by the internal medullary lamina: lateral, medial, anterior
which part of thalamus faces the 3rd ventricle?
Midline/paramedian group faces the CSF in the cavity of the third ventricle. Medial surfaces of each thalamus kiss across the water of the 3rd ventricle (80% ppl), and hence the 3rd ventricle has a little hole in it
do axons cross across thalamus
NO
what is special about the ventral tier of laternal nucleuar group of thalamus?
This region receives ascending sensory projections from below, which project to motor and premotor areas.
What is the VP nucleus?
Ventral posterior (VP) nucleus of thalamus: sensory information through here, and projects to postcentral gyrus (primary somatosensory cortex). Recall that somatosensory fibres ascend in the posterior limb of the internal capsule.
explain the posterior column of spinal cord
gracile (Latin: slender) fasciculus (medial, pretty much next to the posterior sulcus). This contains the dorsal column for the lower limbs (legs), and carries info from below T6. Sensation (vibration best test = tuning fork). cuneate (Latin: wedge-shaped) fasciculus. This is just lateral to the gracile and contains dorsal column for upper limb (arms). Only upper half of cord, info from above T6. Again, tuning fork best test.
best way to test dorsal column?
tuning fork
where is the corticospinal tract in the spinal cord?
lateral
where is the spinothalamic tract in the spinal cord?
ANTERIOR-lateral, hugging the front side of the butterfly wing.
what does the dorsal column do?
vibration, proprioception, touch
explain pathway of dorsal column pathway
1st order neuron comes in via dorsal root, with cell body in dorsal root ganglion, continues up the dorsal column medulla ˆ great sensory decussation as 2nd order neuron to thalamus VP ˆ 3rd order neuron (thalamocortical neuron) from VP to somatosensory cortex.
where do 1st and 2nd order neurons synapse in dorsal column pathway?
medula
which pathway has great sensory decussation?
dorsal column
what sensations are transmitted by the spinothalamic tract
pain, temperature
where does the spinothalamic tract decussate?
1st-order neuron immediately synapses with the second-order neuron in the spinal cord. Hence, axons immediately cross over at the level where it enters in the ventral white commissure (this is the only one to cross in the spinal cord, the others cross in medulla).
in the spinothalamic tract, do 2nd order neurons ascend up contra- or ipsi-lateral side of spinal cord?
contra
What is special about the sense of smell compared to the other senses (in particular, the route by which information about odorants reache the cerebral cortex)?
Primitive route, does NOT go via thalamus, but goes direct to cortex. (ia limbic system)
What might be the effect of ventral posterior nucleus infarction?
contralateral sensation loss
What visual field defect would you expect in a complete infarction of the left lateral geniculate nucleus?
right hononymous hemianopia
Hemisection of the left spinal cord would cause paralysis on which side of the body?
left
Hemisection of the left spinal cord would cause loss of vibration sense on which side?
left
Hemisection of the left spinal cord would cause pain and temperature loss on which side?
right
What is brown sequard syndrome?
hemisection of spinal cord: causes motor loss ipsilateral side, vibration/touch/proprioception loss ipsilateral side, pain/temperature loss contralateral side
What is the best way to assess the integrity of the dorsal columns at the bedside?
vibration (tuning fork)
What symptoms and signs might be caused by disease of the posterior columns?
Loss of touch and proprioception in ipsilateral side. Sensory ataxia (you can have Cb ataxia but that is due to coordination problem, whereas this is due to sensory problem)
What is the best way to assess the integrity of the spinothalamic tract at the bedside?
pin test
Where might a neurosurgeon cut the spinal cord to treat severe, chronic pain?
Anterior: to interfere with spinothalamic tract to try and stop pain ascending, but it usually doesnÕt work
Why might a drug that interferes with re-uptake of serotonin (e.g. an antidepressant) have an analgesic effect?
Serotonin is part of the descending inhibitory pathway than reduces pain
is VP thalamus part of motor, sensory or both tracts?
sensory only
is posterior limb of internal capsule for motor, sensory or both?
both
The deep pelvic veins are linked to the internal vertebral venous plexus; what might this valveless connection facilitate in a patient with a pelvic malignancy (e.g. prostate cancer)?
Metastasis to spine
What acute event (a neurosurgical emergency) might spinal metastasis lead to?
Acute cord compression _ sacral will be damaged first (see drawing)
What are the Ôred flagÕ signs to look out for, wrt acute cord compression?
Perianal anesthesia
acute cord compression: why is patient said to be sitting on their clinical signs?
Due to perianal anesthesia
What does rubbing a sore knee have to do with the dorsal horn of the spinal cord?
Rubbing: sensory input via dorsal root. This inhibits transmission of pain via C fibres
Loss of the biceps reflex implies disease at which root level?
C5/6
At what level is a lumbar puncture performed _ and why?
level of cord to avoid cord damage but still get CSF. L3-L4.
If you could selectively sever the sympathetic supply to the upper limbs, could this be used to treat palmar hyperhidrosis (excessively sweaty palms)?
Yes. SYM innervates sweat glands.
Excessive sympathetic activity can cause RaynaudÕs phenomenon, characterised by spasm (vaso-constriction) of the digital arteries; in this condition, why do the fingers turn white, then blue, then red?
High SYM due to emotion or cold. Blood diverted away from peripheries. White due to inadequate (no) blood flow, blue because blood returns and oxygen-starving tissues rip off oxygen from the blood so the blood quickly goes blue, red due to returning oxygenated blood flow
