Brain and Spinal Cord Flashcards
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?
Denticulate ligament.
What is the name of the tapering off of the spinal cord at L1/L2?
Conus medullaris.
What is the name of all the nerve roots in the lumbar cistern?
Cauda equina.
What is the name of the thin string of pia mater that anchors the end of the spinal cord to S2?
Filum terminale.
What is the name of the ligament between the spinous processes of the vertebrae?
Interspinous ligament.
What is the name of the ligament along the posterior of the spinous processes of the vertebra?
Supraspinous ligament.
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>
Ligamentum nuchae.
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?
Ligamentum flavum.
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?
Irregular.
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?
A bat.
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?
Midbrain
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?
Contralateral hemiparesis.
What does a lesion in the primary sensory cortex of one hemisphere cause?
Contralateral hemianaesthesia
What does a lesion in the primary visual area of one hemisphere cause?
Contralateral hemianopia
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?
60-80%
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?
Abstract thinking Decision making Prioritising and sequencing Goal directed behaviour Inhibitions (ability to be socially acceptable)
What does a lesion of the prefrontal cortex cause?
Disinhibition Changes in personality and social function Decreased concentration Decreased judgement Decreased abstract thought Decreased foresight Decreased tact 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)