Flashcards in Brain and Spinal Cord Deck (175):
Where are the superior and inferior colliculi?
On the back of the midbrain (tectum).
What are the crus cerebri?
Cerebral peduncles connecting the midbrain to the cerebral hemispheres.
What do the superior, middle and inferior cerebellar peduncles connect?
Superior peduncles = midbrain to cerebellum.
Middle peduncles = pons to cerebellum.
Inferior peduncles = medulla oblongata to cerebellum.
What is the epidural space?
A space outside the dura covering the spinal cord that is filled with fat and blood vessels.
What is the name of the lateral thickenings of the pia mater that anchor the spinal cord into the centre of the vertebral foramen?
What is the name of the tapering off of the spinal cord at L1/L2?
What is the name of all the nerve roots in the lumbar cistern?
What is the name of the thin string of pia mater that anchors the end of the spinal cord to S2?
What is the name of the ligament between the spinous processes of the vertebrae?
What is the name of the ligament along the posterior of the spinous processes of the vertebra?
What is the name of the ligaments along the front and back of the vertebral bodies?
Anterior longitudinal ligament, and posterior longitudinal ligament.
What is the name of the ligament that extends from the external occipital protuberance to the spinous process of C7 and is continuous with the supraspinous ligament>
Where is the central sulcus?
Between the frontal and parietal lobes.
What is either side of the central sulcus?
Pre-central gyrus = primary motor cortex.
Post-central gyrus = primary somatosensory cortex.
Where is the lateral fissure/sulcus?
Between the temporal lobe and the frontal and parietal lobes.
What is the name of the ligament that link the vertebrae together at the back of the central canal?
What is the insula?
An embedded lobe of cerebral cortex behind the lateral fissure, from the folding of the parietal and temporal lobes.
The cerebrum has sulci and gyri, what does the cerebellum have?
Folia and sulci.
What are the 3 lobes of the cerebellum?
Paleocerebellum (anterior), neocerebellum (posterior), and flocculonodular lobe.
Also, two lateral hemispheres and a vermis if you look at it the other way.
Name three structures found in the tegmentum of the brainstem.
Substantia nigra, peri-aqueductal grey matter, red nucleus.
What type of bones are vertebrae?
What does the sacral spinal cord look like?
Grey matter takes up much more space than white matter.
What does the cervical spinal cord look like?
White matter takes up much more space than grey matter.
What does the grey matter of the lumbar spinal cord look like?
A backwards butterfly.
What does the grey matter of the thoracic spinal cord look like?
What sort of bleeds are subdural haemorrhages, and subarachnoid haemorrhages?
Subdural = venous.
Subarachnoid = arterial.
What is conveyed in the anterior spinothalamic tract and what is conveyed in the lateral spinothalamic tract?
Anterior spinothalamic = crude touch.
Lateral spinothalamic = pain and proprioception.
What is conveyed by the anterior spinocerebellar tract, and what is conveyed by the lateral spinocerebellar tract?
Anterior spinocerebellar = ipsilateral movement control.
Lateral spinocerebellar = contralateral unconscious proprioception from muscle spindles.
What is conveyed by the dorsal-columns medial lemniscus tract?
Fine (discriminative) touch, vibration, pressure, conscious proprioception.
Fibres from which region travel in the fasciculis gracilis of the dorsal colums?
Lower limbs and lower trunk.
Fibres from which region travel in the fasciculis cunneatus of the dorsal colums?
Upper limbs and upper trunk.
What is the Lissaeur tract?
The fibres of the spinothalamic tract which decussate after ascending 2 spinal segments rather than immediately.
Give an example of an upper motor neurone lesion, and the characteristic symptoms.
Stroke. Muscle weakness, increased spasticity (hypertonia), increased reflexes (hypereflexia), clasp knife response, positive Babinski's test.
Give an example of a lower motor neurone lesion, and the characteristic symptoms.
ALS (motor neurone disease). Muscle weakness, muscle wasting, flaccid muscles (hypotonia), decreased or absent reflexes, fasciculations.
Name some of the tests for brainstem death.
Lost the capacity to regain consciousness (reticular activating system is in brainstem).
Lost capacity to breathe independently, and lost cardiovascular centre.
Absent pupillary reflex (pupil doesn't contract when light is shined in eye).
Absent vestibulo-occular reflex (eyes don't move when ice cold water put in ears).
Absent gag reflex.
Absent corneal reflex.
Absent motor responses to somatic stimulation (e.g supra-orbital pressure).
What is the difference between a 1a sensory afferent and a 1b sensory afferent from a muscle?
The 1a sensory afferent comes from the intrafusal fibres of the muscle spindle, and is involves in the stretch reflex. The 1b sensory afferent comes from the collagen fibrils of the golgi tendon organ, and is involved in the inverse stretch reflex.
What is the difference between an alpha motor neurone and a gamma motor neurone?
An alpha motor neurone innervates the extrafusal muscle fibres, a gamma motor neurone innervates the intrafusal muscle fibres of the muscle spindle to ensure the spindle stays sensitive to the stretch of the extrafusal fibres.
What is derived from the alar plate and basal plate in the embryo?
Alar plate = dorsal horn.
Basal plate = ventral horn.
Which cranial nerves supply the pharyngeal arches?
Arch 1 = trigeminal nerve
Arch 2 = facial nerve
Arch 3 = glossopharyngeal nerve
Arch 4 = superior laryngeal branch of vagus
Arch 6 = recurrent laryngeal branch of vagus
What are the grooves and ridges called on the cerebral hemispheres, and what are they called on the cerebellum?
Cerebrum = sulci and gyri
Cerebellum = sulci and folia
Where is the angular gyrus?
Brodmann's 39, at the back of the lateral sulcus.
Where is the supramarginal gyrus?
Above the lateral fissure, behind the post-central gyrus (Brodmann's area 40).
What is Brodmann's area 6 called on the lateral aspect and on the medial aspect of the cerebrum?
Lateral = premotor cortex
Medial = supplementary motor cortex
What's the paracentral lobule?
Brodmann's areas 4, 3, 2, 1, 5 on the medial surface where they are not separated by the central sulcus (so it is a mixture of motor and sensory areas).
Which bit of brain is enclosed by the two posterior cerebral arteries?
What is hemispheric lateralisation?
The hemispheres are dominant in different functions e.g analytical functions and language comprehension are lateralised more in the left hemisphere than the right, emotional thinking and spatial orientation and artistic and musical abilities are lateralised more to the right than left.
What does a lesion in the primary motor cortex of one hemisphere cause?
What does a lesion in the primary sensory cortex of one hemisphere cause?
What does a lesion in the primary visual area of one hemisphere cause?
Which bit is the primary motor cortex?
Precentral gyrus, Brodmann's area 4
Which bit is the primary somatosensory cortex?
Postcentral gyrus, Brodmann's 3, 2, 1
Which bit is the frontal eye field and what does it do?
Brodmann's area 8, it moves both eyes towards the contralateral side.
What does a lesion in the supramarginal gyrus (40) lead to?
A loss of left-right discrimination, contralateral tactile and proprioceptive agnosia (inability to identify something by touch), contralateral apraxia (inability to perform purposeful tasks), contralateral hemineglect.
What is the angular gyrus (39) important for, and what does a lesion result in?
Important for language comprehension and reception.
Lesion results in alexia (difficulty understanding strings of letters as sentences), dyslexia (difficulty reading), agraphia (inability to write).
Where is the expressive speech area, and what does a lesion result in?
Broca's area (44 and 45 on the inferior frontal gyrus). Lesion results in expressive (motor) aphasia.
Where is the receptive speech area, and what does a lesion result in?
Wernické's area (39 and 22 at junction between temporal and parietal and occipital lobes). Lesion results in receptive (sensory) aphasia - not understanding own words or noticing mistakes, neologisms (making words up).
Where is the hearing area?
The back of the superior temporal gyrus (Brodmann's 22, 41, 42), and both ears are represented bilaterally.
Where does the middle cerebral artery arise from?
It is a continuation of the internal carotid artery after if has given rise to the anterior cerebral artery.
What proportion of the blood in the internal carotid artery does the middle cerebral artery receive?
Where does the middle cerebral artery run and which parts does it supply?
It runs along the insula in the lateral fissure, and supplies most of the lateral area of the cerebral hemispheres (including the speech areas, frontal eye field, motor and sensory areas for the face and arm, most of the basal ganglia and thalamus).
What 6 things are caused by a middle cerebral artery stroke?
1) contralateral upper motor neurone hemiparesis (more in upper limb than lower limb)
2) contralateral hemianaesthesia (more in upper than lower limb)
3) contralateral hemianopia (although primary and accessory visual areas are not affected, the basal ganglia and internal capsule are)
4) frontal eye field loss (so eyes deviate towards the side with the lesion)
5) global aphasia (all the language centres in the dominant hemisphere have been lost)
6) anosognosia (reduced self awareness due to loss of supramarginal gyrus)
What functions is the prefrontal cortex involved in?
Prioritising and sequencing
Goal directed behaviour
Inhibitions (ability to be socially acceptable)
What does a lesion of the prefrontal cortex cause?
Changes in personality and social function
Decreased abstract thought
Decreased problem solving ability
Where does the anterior cerebral artery arise and run to?
Arises from internal carotid artery, then tracts around the corpus callosum (pericallosal).
Which parts of the cerebrum does the anterior cerebral artery supply?
Medial surface of frontal and parietal lobes (so bit dedicated to pelvis and legs and feet), but does not supply beyond the parieto-occipital sulcus.
Which branch of the anterior cerebral artery supplies the internal capsule, putamen and caudate nucleus?
The medial striate artery (of Heubner)
What 3 things are caused by an anterior cerebral artery stroke?
1) Prefrontal cortex lesion (causing disinhibition)
2) Contralateral upper motor neurone hemiparesis (affecting lower limb more than upper limb)
3) Contralateral hemianaesthesia (affecting lower limb more than upper limb)
Where is the primary visual area?
Brodmann's 17 either side of the calcarine sulcus in the occipital lobe.
Where are the association visual areas?
Brodmann's 18 and 19, either side of the primary visual area (17).
What is caused by a lesion in the primary visual cortex?
Contralateral homonymous hemianopia (lose sight on same side of both eyes)
What is the function of the primary visual area and f the association visual area?
17 - tells you that you see (lesion can lead to "blind sight" if association areas still intact)
18 + 19 = recognise what you see (lesion leads to visual agnosia)
Where does the posterior cerebral artery arise and where does it run?
Arises as the terminal branch of the basilar artery, runs either side of the midbrain to the occipital lobe.
What does the posterior cerebral artery supply?
The midbrain, the splenium of the corpus callosum, the thalamus and basal ganglia, the occipital lobe (including primary visual cortex).
What are the posterior choroidal arteries?
Arise from posterior cerebral artery and supply occipital lobe.
What 4 things are caused by a stroke in the posterior cerebral artery?
1) Visual agnosia
2) Contralateral homonymous hemianopia
3) Contralateral hemianaesthesia
4) Alexia and dyslexia
3 and 4 are caused because the areas supplied by the posterior cerebral artery overlap with the middle cerebral artery
What is the venous drainage of the brain?
Superior sagittal sinus in longitudinal fissure.
Inferior sagittal sinus joins great cerebral vein to form straight sinus which runs to confluence of the sinuses.
Transverse sinus runs round to sigmoid sinus which pours into internal jugular vein.
What do Aalpha fibres transmit?
Conscious proprioception from muscle fibres.
What do Abeta fibres transmit?
Fine touch and vibration from skin mechanoreceptors.
What do Adelta fibres transmit?
First pain and temperature.
What do C fibres transmit?
Second pain and temperature.
What is the best treatment for s herniated disc?
Resuming normal activities.
What is pilocarpine?
A muscarinic antagonist
Where is the cell body of the first order sensory neurone?
In the dorsal root ganglion.
What is ondansetron?
A 5-HT receptor antagonist which treats nausea and vomiting caused by chemotherapy and radiotherapy.
Where is the confluence of the sinuses?
Where the superior sagittal sinus joins the straight sinus and bifurcates into the transverse sinuses.
What are the three folds of the dura mater?
Falx cerebri - in longitudinal fissure
Fals cerebelli - in vallecula between two cerebellar hemispheres
Tentorium cerebelli - between cerebellum and inferior portion of occipital lobes
What are the four parts of the corpus callosum from front to back?
Rostrum, genu, body, splenium
What is the name of the sulcus that runs along the top of the corpus callosum?
What is the name of the sulcus on the medial aspect which runs from the parieto-occipital sulcus to the apex of the occipital lobe?
What is the name of the sulcus that runs along the top of the cingulate gyrus on the medial aspect?
What is the name of the gyrus running along the top of the corpus callosum on the medial surface?
What is the name of the sulcus between the pre central (4) and post central (3,2,1) gyri?
What is the name of the sulcus between the temporal lobe and the parietal and occipital lobes?
Lateral sulcus/Sylvian fissure.
What covers the insula?
The parietal, temporal and frontal opercula (sing. = operculum).
What are the crus cerebri?
Cerebral peduncles from the midbrain to the cerebrum.
What is the name of the groove between the crus cerebra, and what are its borders?
Bordered anterolaterally by optic trays and optic chiasm, bordered posterolaterally by the crus cerebra, bordered posteriorly by the pons.
Where is the hypothalamus?
Below the thalamus, forming the ventral part of the diencephalon.
What is the pituitary stalk?
The link between the hypothalamus and pituitary gland.
What connects the lateral ventricles to the third ventricle?
Interventricular foramen (of Monro).
What connects the third ventricle to the fourth ventricle?
What is always the grey matter immediately lateral to the lateral ventricles?
What is the lentiform nucleus?
The putamen and internal and external segment of the globes pallidus.
What is the grey matter seen if you move laterally to medially starting at the insula?
Insula -> extreme capsule -> claustrum -> external capsule -> putamen -> globus pallidus pars external -> globes pallidus pars internal
Where is the amygdala?
Just anterior to the hippocampus in the medial temporal lobe.
Where is the anterior limb of the internal capsule?
Between the lentiform nucleus and the caudate nucleus.
Where is the posterior limb of the internal capsule?
Between the thalamus and the lentiform nucleus.
Where does the anterior spinal artery connect?
To the vertebral arteries just before they join to form the basilar artery.
Where do the posterior spinal arteries connect?
They branch off the posterior inferior cerebellar arteries which branch off the vertebral arteries.
Where do the anterior inferior cerebellar arteries arise?
The bottom of the basilar artery.
Where do the superior cerebellar arteries arise?
From the basilar artery just before it bifurcates into the posterior cerebral arteries.
Where is the anterior communicating artery?
Between the two anterior cerebral arteries.
Where is the posterior communicating artery?
Between the internal carotid artery and posterior cerebral artery.
What are the only parts of the nervous system where there are nerves that are purely sensory or purely motor?
Dorsal and ventral roots of spinal cord.
What do spinal nerves bifurcate to form?
A primary dorsal ramus and a primary ventral ramus.
What do the dorsal rami of spinal nerves supply?
The section either side of the vertebral column at the back e.g the erector spinae muscles.
Where does the spinal cord end?
The conus medullaris is at the junction between L1 and L2.
Which vertebrae does the film terminal attach to?
What are the roots of plexuses?
Why are plexuses important?
They efficiently redistribute nerves to different areas of the body, and can run along more protected places e.g inside of limbs.
What is a myotome?
A unit of muscle that is innervated by a single spinal segment.
What is a dermatome?
An area of skin innervated by a single spinal segment.
About how long is the spinal cord, and how much of the vertebral column does it occupy?
42-45cm, fills 2/3 of the vertebral column.
Where are the two enlargements of the spinal cord, and why is it enlarged?
Cervical (C3-T1), and lumbosacral (L1-S3)
It is enlarged due to the large number of lower motor neurones going to the upper and lower limbs.
For how many months in the embryo are the vertebral column and spinal cord the same length, before the vertebral column begins to grow faster?
First 3 intrauterine months.
In which meningeal space is the caudal equina?
Sub arachnoid, like all the nerve roots.
How do the relative amounts of grey and white matter change as you descend the spinal cord?
At the top there is a lot more with matter than grey matter, but as you move distally the grey matter starts to predominate.
At which vertebral levels is there a lateral horn in the spinal cord?
T1 to L2, corresponding to the region where sympathetic nerves arise.
Where do first order neurones carry impulses?
From the receptor to the second order neurone in the spinal cord or medulla oblongata/
Where do second order neurones carry impulses?
Second order neurones are the ones that decussate.
They carry impulses from the first order neurones in the spinal cord or medulla oblongata to the third order neurones in the thalamus.
Where do third order neurones carry impulses?
From the second order neurones in the thalamus, through the internal capsule to the primary somatosensory area of the cortex.
What are the three curvatures of the vertebral column?
Cervical lordosis, thoracic kyphosis, lumbar lordosis.
How many of each type of vertebra are there?
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
What do you call the joint between a superior articular process and inferior articular process of neighbouring vertebrae?
Where on the vertebral arch are the pedicles, and where are the laminae?
The pedicles connect the transverse processes to the vertebral body, the laminae connect the spinous process to the transverse processes.
C1 and C2 are atypical, what are they called and how do they articulate?
C1 = atlas
C2 = axis
Atlas articulates with the skull at the atlanto-occipital joint which allows flexion and extension.
Axis articulates with atlas at the Atlanta-axial joints. The odontoid process (dens) projects up from axis into altas.
What are the characteristics of a typical cervical vertebrae?
Transverse foramen which the vertebral arteries run.
Large vertebral arch with small vertebral body as they're not carrying much weight.
Bifid spinous process.
Horizontal zygapophyseal joints which make rotation easier.
What are the characteristics of a typical thoracic vertebrae?
Costal facets on the transverse processes for articulation with ribs.
Long spinous processes pointed downwards to protect spinal cord.
Vertical zygapophyseal joints.
C7 most prominent spinous process.
What are the characteristics of a typical lumbar vertebrae?
Large kidney shaped vertebral bodies, they bear a lot of load.
Small vertebral arches, because there is no spinal cord, just a cauda equina.
Large spinous process.
Vertical zygapophyseal joints.
Big intervertebral discs to allow compression, extension in movement.
Which hole do spinal nerves exit through?
The intervertebral foramen
What is the difference between how structural and postural deformities of the spine respond to passive movement?
A structural deformity will not be corrected by passive movement, a postural deformity can be corrected by passive movement.
Where does the sciatic nerve arise and run?
Arises from L5-S2 and runs down the back of the leg, supplying the knee flexors.
Where does the femoral nerve arise and run?
Arises from L2-L4 and runs down front of leg, supplying hip and knee joint and knee extensors.
What are the symptoms of cauda equina syndrome?
New sexual dysfunction
Bilateral leg weakness
Which dermatome is the nipple, and which is the umbilicus?
Nipple = T4
Umbilicus = T10
Where are the cell bodies of the 12 cranial nerves?
First 2 in the cerebral cortex or diencephalon
Next 2 in the midbrain
Next 4 in the pons
Last 4 in the medulla
What features are found on the back of the midbrain (tectum)?
Superior colliculus, inferior colliculus.
Which is the only cranial nerve which comes out of the dorsal aspect of the brainstem and runs forward?
Cranial nerve 4
Which type of lower motor neurone innervates the extrafusal muscle fibres, and which innervates the intrafusal muscle fibres?
Alpha motor neurone innervates extrafusal muscle fibres (final common pathway).
Gamma motor neurone innervates intrafusal muscle fibres.
What is the largest bundle of commissural fibres (fibres that cross the midline)?
What are association tracts?
Axons between gyri in the same hemisphere.
What are commissural tracts?
Axons from gyri in one cerebral hemisphere to the corresponding gyri in the other cerebral hemisphere.
What are projection tracts?
Axons from the cerebrum to the lower parts of the CNS (thalamus, brainstem, spinal cord) and back up e.g internal capsule.
How are the Brodmann's areas defined, and how many are there in total?
Defined changes in the cytoarchitecture (histology) of the cortex, so within each area the cytoarchitecture is the same.
There are 47 areas in total.
Correspond well to the functional areas of the brain.
Between which two Brodmann's areas is the central sulcus?
Brodmann's 4 and 3.
Which parts of the body are represented on which parts of the pre and post central gyri?
Imagine bugs bunny sitting on Bazira's brain so his legs and feet are dangling into the longitudinal fissure and he's lying back so his ears flop over Bazira's ears.
Why do the hands and face have bigger areas of the cortex devoted to them?
The more control you need over an organ, the bigger the area of cortex devoted to it.
What are the three cerebellar lobes?
Flocculonodular system - vestibulocerebellum (output via fastigial nucleus or direct to spinal cord)
Paleocerebellum (anterior lobe) - gait and trunk
Neocerebellum (posterior lobe) - finer movements of arms and hands
What is the name of the fissure separating the anterior and posterior cerebellar lobes on the superior surface?
What is the name of the fissure separating the posterior cerebellar lobe and the flocculonodular cerebellar lobe?
How many deep cerebellar nuclei are there and which is the wiggly one that's always visible on a section of the cerebellum?
4 - dentate nucleus is most visible.
Does a lesion in one cerebellar hemisphere lead to ipsilateral or contralateral loss of co-ordination and ataxia?
Ipsilateral - the cerebellum receives ipsilateral input from muscle proprioceptors, vestibular nuclei, auditory and visual.
What is the main efferent pathway of the cerebellum called?
What is always the grey matter just lateral to the lateral ventricle?
What is the grey matter just lateral to the third ventricle?
What are the three parts of the lateral ventricle?
Frontal horn, occipital horn, temporal horn
What are the bits of grey matter above and below the temporal horn of the lateral ventricle?
Above = caudate nucleus
Below = hippocampus
Which artery supplies the basal ganglia?
Middle cerebral artery
Which artery supplies the hypothalamus?
Anterior communicating artery
Which artery supplies the posterior limb of the internal capsule?
Posterior cerebral artery
Which arteries supply the anterior limb and genu of the internal capsule?
Middle cerebral artery and anterior cerebral artery
What is the groove in the sphenoid bone called that the pituitary gland sits in?
Sella turcica (pituitary fossa)
Which ventricle is the hypothalamus in the lateral wall of?
What is the hypothalamic sulcus?
A groove in the lateral wall of the third ventricle from the inter ventricular foramen (of Monro) to the cerebral aqueduct.
What is the name of the this sheet of dura covering the pituitary gland?