Anatomy Flashcards
1
Q
At what days does the neural tube close?
A
Day 24-25
2
Q
Describe how the adult brain forms from 3 primary vesicles and then five secondary vesicles
A
1º Brain Vesicles (x3) Prosencephalon, Mesencephalon, Rhombencephalon
2º Brain Vesicles (x5) Telencephalon (hemispheres), Diencephalon (thalamus, Central), Mesencephalon (midbrain), Metencephalon (pons), Myelencephalon (medulla)
3
Q
What makes up the CNS?
A
Brain, spinal cord, retina & CNII
4
Q
What are the 3 branches of the motor efferent pathway?
A
Somatic motor
Brachio motor - pharyngeal arch muscles, cranial nerves
Visceral/autonomic motor
5
Q
What are 3 branches of the sensory afferent pathway?
A
Somatic sensory
Visceral sensory
Special visceral sensory - taste
6
Q
What are the 3 meningeal layers in the CNS?
A
Dura: Periosteal layer - Thick, fibrous and leathery
Dura: Meningeal layer
Arachnoid mater - Thin and web/lace-like
Pia mater - Thin & adherent to cortex
7
Q
Where do you find CSF in the CNS?
A
Sub arachnoid space
8
Q
What is the falx cerebri?
A
Double-layered inward projecting fold of dura in sagittal plane
Prevents left and right cerebral hemispheres from spinning during axial head rotation
9
Q
What is the Tentorium cerebelli?
A
Double-layered inward projecting fold of dura
Prevents occipital lobe compressing the cerebellum especially during flexion & extension
10
Q
What is the Falx cerebelli?
A
Double-layered inward projecting fold of dura
Prevents left and right cerebellar hemispheres from rotating
11
Q
What is the Diaphragm Sellae?
A
Double layered fold of dura
Forms protective pocket for pituitary
12
Q
Where does blood from the CNS drain?
A
Dural venous sinuses located between two layers of dura
Sinuses are valveless & endothelial lined
13
Q
Name the venous sinuses
A
Superior sagittal sinus Inferior sagittal sinus Straight sinus Transverse sinus Sigmoid sinus Right cavernous sinus
14
Q
What can blockage of venous sinus drainage cause?
A
Cerebral infarction
15
Q
Which arteries anastamose to form the circle of Willis?
A
Internal carotid
Vertebral artery
16
Q
What separates the cerebral hemispheres?
A
Longitudinal fissure
17
Q
What separates the frontal and temporal lobes?
A
Lateral/Sylvian fissure
18
Q
What structure connects the cerebral hemispheres?
A
Corpus callosum
19
Q
Name the cranial nerves
A
1 olfactory 2 optic 3 occulomotor 4 trochlear 5 trigeminal 6 abducens 7 facial 8 vestibulocochlear 9 glossopharyngeal 10 vagus 11 accessory 12 hypoglossal
20
Q
Describe where the cranial nerves emerge
A
CN III & IV: Midbrain CN V: Pons CN VI –VIII: Pontomedullary junction CN IX & X: Lateral medulla CN XI: C1-C5 spinal cord CN XII: Ventral medulla
21
Q
Where and what are the Cerebral peduncles?
A
Anterior Midbrain
Axons to and from cerebral hemispheres
22
Q
Which is the only cranial nerve visible posteriorly?
A
CN IV - trochlear
23
Q
What and where are the superior and inferior colliculi?
A
Posterior midbrain
Superior - linked to visual
Inferior - linked to auditory
24
Q
Where do Cranial nerves exit the cranium?
A
Foramen magnum in the skull base
25
What will result from dysfunction of the cerebellum?
ataxia, wide-based gate, slurred speech, imbalance, nystagmus
26
What are the main functions of the cerebellum?
Coordination of motor activity
Involved in stabilisation of body (trunk & limbs), memory, cognitive functioning, language processing, logical reasoning
Automates many processes e.g. motor skills, language
Predicts sensory consequence of movements by comparison to previous experience
Frees cerebral cortex for higher level functions
27
What are the 3 main lobes of the cerebellum?
Anterior
Posterior
Flocculonodular
28
What are the ventricles?
Cerebrospinal fluid filled chambers within the subcortical regions of the
brain. Associated with many nuclei. And functional regions of the brain.
Produce CSF via choroid plexus
29
What are nuclei?
Collections of neuronal cell bodies with similar functions and projections. Normally found in subcortical areas at points of synapse
30
What are Brodmann areas?
Cerebral cortex is arranged into regions with specified functions Brodmann classification is based on cyto-architectural/histological structure of the cortex
31
Where is the primary auditory cortex?
Temporal lobe
| Brodmann area 41
32
Where is the primary visual cortex?
Occipital lobe
| Brodmann area 17
33
Where is the primary somatosensory cortex?
Parietal cortex, post central gyrus
| Brodmann area 1
34
Where is the primary motor cortex?
Frontal lobe, pre Central gyrus
| Brodmann area 4
35
Which side of the cortex looks after speech, writing and language?
Left
36
Which side of the cortex looks after special perception and facial recognition?
Right
37
What is synaesthesia?
combination of senses that provides an unusual interpretation
Eg See colour, shapes, textures when hearing sound or words, Experience taste when reading numbers
38
What is Prosopagnosia?
inability to recognise faces
39
What are commisural fibres?
White matter structures that connect hemispheres
40
What are association fibres?
Connect regions within the same hemisphere
41
What are projection fibres?
Connect each region to other parts of the brain or the spinal cord
42
What is Brocas area?
Motor planning involved in speech in frontal lobe
43
What is a Fasciculus?
Bundle of fibres sharing a similar function and route of travel
44
What is Wernickes area?
Understanding/interpreting heard, spoken and written word
| In termporal lobe
45
What connects Wernickes area and Broca's area?
Arcuate Fasciculus
46
What is a Jeffersons fracture?
Fracture of anterior and posterior arches of C1 vertebra
47
What are advantages and disadvantages of xrays?
Fast, Cheap, Good bone detail, Dynamic images
| 2-D, Poor soft tissue detail, X-ray dose
48
What are advantages and disadvantages of ultrasound?
Fast, Cheap, Dynamic images, No radiation
| 2-D, Poor soft tissue detail, Operator dependent
49
What role does CT imaging play?
A + E, Trauma - haematomas + fractures, Stroke - haemorrhage, Severe headache - SAH, meningitis, Unconscious patient, Hydrocephalus, CT guided biopsies
50
Describe CT - intravenous contrast
Iodine based injection to highlight pathology and increase contrast
Hot flush and odd taste
Appears white on CT
Vessels, pituitary + choroid plexus normally enhance
Other enhancement indicates leaky BBB
1/40,000 anaphylaxis: give asthmatics steroid cover
51
What pathologies can be seen more easily with CT contrast?
Cerebral abscesses
| Tumour - glioma
52
What are advantages and disadvantages of CT?
Excellent bone detail, Good for blood + Ca, Good soft tissue detail, Quiet and spacious, CT guided biopsy, 3-D,
Expensive, Very high X-ray dose
53
In MRI T1 and T2 assessments, what colour is the CSF?
T1 - black
| T2 - White
54
What is gadolinium?
Contrast medium used in MRI
55
What are advantages and disadvantages of MRI?
No X-rays, Exquisite anatomy, Excellent soft tissue detail, Multiplanar acquisition
Slow, Expensive, Claustrophobic + noisy, Poor bone detail, Contraindications: Metal implants and foreign bodies, pacemakers
56
Before being scanned in MRI, patients need to complete a screening questionnaire. Objects to be particularly wary of are...?
Cardiac pacemakers:- some are electrically or magnetically activated (possible death), pacing wires can cause burns
Aneurysm clips:- if ferromagnetic can move causing re-bleed and death
Electronic implants:- magnetic can reset or destroy
Metal in eye:- can move severing optic nerve
57
What is the role of digital subtraction angiography?
Gold standard for intracranial haemorrhage, aneurysm, arterio-venous malformation / fistula, Assessment of carotid stenosis, Embolisation
58
What can be a risk of a pituitary tumour?
Compression of optic nerve
59
Which artery do you find in the Sylvian fissure?
Middle cerebral artery
60
What is diffusion weighted MRI imaging useful for?
Infarct, Abscess, Cyst, Tumour, Prion disease
61
Describe a subdural haematoma
```
Contracoup - occurs on opposite side to area of injury
Crescentric and thin
Can cross sutures except sagittal
Do not cross tentorium
Flattens the sulci
Mass effect
```
62
Describe and extradural haematoma
```
Coup - at site of injury
Concentric
Do not cross sutures
Can cross tentorium
Often underlying fracture
Often contralateral subdural
Poor prognosis: > 2cm, central lucency, > 1.5cm midline shift
```
63
Describe a haemorrhagic contusion
Mild: limited to grey matter
Moderate: involves white matter
Severe: haemorrhages coalesce
Haemorrhage may be delayed
64
Where can herniation occur?
Uncal/transtentorial
Tonsillar
Subfalcine
65
What is functional MRI?
```
Uses different paramagnetic properties of oxygenated and deoxygenated Hb
Is a measure of cortical brain activity
Can be combined with an EEG
Pre surgical planning
Research tool
```
66
What can a DAT scan be used for?
Parkinson's disease diagnosis
| SPECT images of brain, particularly the striatum
67
What is MR spectroscopy used for?
Provides information on biochemical and metabolic composition of tissues
Good for tumour - Glioma vs other mass lesion, Tuberculoma, Leukodystrophies
68
What is the lateral geniculate body of the thalamus?
Relay for optic tract fibers
69
What is the medial geniculate body of the thalamus?
Relay for auditory pathway fibres
70
What is the ventral posterior nucleus of the thalamus?
Ventral Posterior Lateral nucleus - Body
Ventral Posterior Medial nucleus - Face – CN V
Sensory relay nucleus of multiple modalities from body & face (touch, pain, temperature, taste). Input from spinothalamic tract, medial lemniscus & trigeminothalamic tracts
71
What symptoms can damage to the thalamus cause?
Contralateral motor & sensory functions
Contralateral part of visual field of each eye
Effects on memory, emotion & mood
Certain lesions can cause pain (thalamic syndrome)
72
Which cranial nerve emerges from the dorsal midbrain and decussates?
Trochlear - IV
73
Which cranial nerves could be compressed by a 4th ventricle tumour?
CN VI nucleus and VII wound around
74
Where does most nociception from CN VII, IX, X pass?
Via CN V sensory nucleus
75
Describe cortical connections to brainstem motor nuclei and the exceptions to the normal pattern
Bilateral supply from the motor cortex
Innervation from corticobulbar/corticonuclear neurons
The majority of UMN innervation comes from contralateral cortex
Cerebral cortex infarction causes an initial contralateral weakness/paralysis that can recover with time due to ipsilateral supply
Exception - Unilateral supply to CN VII nucleus for lower face
And CN III, IV & VI – have a different innervation pattern
76
Describe the process of forehead sparing in some facial nerve lesions
CN VII Nucleus receives bilateral & unilateral innervation from the cortex
Forehead part of the nucleus receives bilateral UMN innervation
Lower face part receives only contralateral UMN innervation
UMN lesion results in paralysis of the contralateral lower face with forehead sparing due to ipsilateral supply
77
What is a bulbar palsy?
Lower motor neurone lesion affecting CN VII - XII
Paralysis of pharynx, soft palate, larynx, tongue (sometimes face & mastication)
Dysarthria, dysphonia, drooling, poor swallowing, aspiration
Flaccid paralysis, wasting, fasciculations
Causes = Polio, radiotherapy, CVE
78
What is pseudo bulbar palsy?
Bilateral corticobulbar tract disorder (upper motor neurone lesion)
Presents initially as LMN lesion
Bilateral damage is clinically significant
Similar symptoms to bulbar palsy but can develop spastic paralysis of
pharynx & larynx = airway occlusion emergency
Causes = Head injury, CVE, high brainstem tumour
79
Describe the vertebrobasilar arterial system
Vertebral arteries combine to form basilar artery along with anterior spinal artery
Basilar gives off pontine branches and superior cerebellar
Then posterior cerebral artery and posterior communicating
80
Aneurysm of which artery could compress cranial nerves 3 and 4?
Superior cerebellar artery
81
Which cranial nerves are supplied by the PICA?
Lateral aspects of the medulla
| CN V, VIII
82
Which parts of the brainstem are supplied by the anterior spinal artery?
Anterior midline medulla
| Corticospinal tracts
83
What are branchio motor structures?
Derived from pharyngeal arches
Muscles of facial expression, mastication, stylopharyngeus (IX), nucleus ambiguus (X - muscles of pharynx, palate, larynx),
CN V, VII, IX, X
84
What does CN III motor nucleus damage cause?
Leads to eye positioned down & out at rest and a full ptosis
85
What is the Edinger Westphal nucleus? And what symptoms would result from damage?
Parasympathetic nucleus involved in pupillary light reflex
| Damage leads to ipsilateral loss of accommodation & pupil light reflex
86
What is the red nucleus?
Linked to cerebellum & rubrospinal tract
| Controls flexor muscle tone; If damaged possible tremor/ataxia of contralateral body
87
What is the medial lemniscus?
Tract carrying contralateral dorsal column fibres
88
Which cranial nerves emerge from the midbrain?
CN III, IV
89
What does damage to CN IV nucleus lead to?
Contralateral loss of superior oblique function
| Diplopia when reading & descending stairs; head tilted toward side of damaged nucleus
90
At what level do the dorsal columns decussate?
Medial lemniscus in the medulla. Cross to anterior part of brainstem
91
What are the 3 parts of the trigeminal nucleus?
Midbrain - proprioception - mesencephalic nucleus
Pons - touch - chief nucleus
Medulla - pain and temp - spinal nucleus
92
Describe the path from the trigeminal nucleus to the sensory cortex
Trigeminothalamic tract decussates
Travels as trigeminal lemniscus
Travels via ventral posteriomedial nucleus of the thalamus to the sensory cortex
93
Which brainstem nuclei are involved in sleep and wakefulness?
Reticular formation
Sleep - Midbrain raphe nuclei (seretonin)
Awake - Cholinergic neurons adjacent to cerulean excite the cortex
via the thalamus
94
Which CNs leave the skull via foramen in the posterior cranial fossa?
CN IX - XII
Jugular foramen IJV & CN IX-XI
Hypoglossal canal CN XII
95
What is the nucleus ambiguus?
Motor supply nucleus to branchiomotor muscles
CN IX (stylopharyngeus)
CN X (pharynx & larynx, upper 1/3 of oesophagus)
Cranial CN XI (larynx)
96
What is the nucleus solitarius?
Special sensory information via visceral afferents
Taste, Visceral sensation (RS & GI), Baroreceptors & chemoreceptors (Carotid body & sinus), pneumotaxic centre etc
97
What does the spinal part of CN XI supply?
Sternocleidomastoid and trapezius muscles
98
What are the 4 medial structures which begin with M in the brainstem?
```
Motor pathways (Corticospinal) - Contralateral weakness of UL/LL
Medial lemniscus (dorsal column) - Contralateral loss of vibration & proprioception
Medial longitudinal fasciculus - No ipsilateral eye adduction on lateral gaze
Motor nuclei of CNIII, IV, VI & XII - Ocular palsies
```
99
What are the 4 lateral structures which begin with S in the brainstem?
Spinocerebellar tract - Ipsilateral limb ataxia
Spinothalamic tract - Contralateral loss of limb pain and temp
Sensory nucleus of CNV - Ipsilateral facial pain and temp sensation loss
Sympathetic fibres - Ipsilateral Horner’s syndrome
100
Which structures leave the skull via the foramen rotundum?
CN Vb
101
Which structures leave the skull via the foramen spinosum?
```
Middle meningeal artery
Meningeal nerve (CNVc)
```
102
Which foramen in the skull do the CN Vc, lesser petrosal nerve and accessory meningeal artery?
Foramen ovale
103
Which structures leave the skull via the superior orbital fissure?
CN III, IV, Va, VI
104
Which foramen do the ophthalmic artery and CN II leave the skull by?
Optic canal
105
Which structures leave the skull via the jugular foramen?
Internal jugular vein & CN IX-XI
106
Which foramen does the hypoglossal nerve leave the skull by?
Hypoglossal canal
107
Which structures leave the skull via the internal acoustic meatus?
CN VII, VIII
108
What is the cavernous sinus?
Large dural venous sinus located to the left and right lateral sides of the pituitary fossa of the sphenoid bone containing internal jugular vein, CN III, IV, VI, Va, Vb
109
Where does the cavernous sinus drain?
Pterygoid venous plexus
110
Aneurysm of the internal carotid can compress nearby structures such as?
Lateral sides of optic chiasm - loss of nasal visual fields
CN VI - cross eyed
Sympathetic nerves to the face - Horners signs
111
What are the ventricles of the brain?
Hollow regions, site of CSF production (500ml/day) via choroid plexus which forms the blood-CSF-barrier
112
What does CSF do?
Support
Cushioning
Transport
113
Where does CSF leave the ventricles?
```
2 Lateral Apertures (Luschka)
Median Aperture (Magendie)
```
114
What connects the lateral ventricles to the 3rd ventricle?
Interventricular foramen (Monro)
115
What connects the 3rd ventricle to the 4th ventricle?
Cerebral aqueduct
116
What does blockage of the ventricular system lead to?
Hydrocephalus
In child - head increase in size due to unfused sutures of skull
In adult - raised ICP
117
Which cells produce CSF?
choroidal ependymal cells
118
What forms the selectivity of the BBB?
Blood CSF barrier - Tight junctions and microvilli between choroidal ependymal cells
Blood ECF barrier - between capillary beds and neural tissue. Endothelial cells bound by tight junctions
119
How much CSF is present at any one time?
150ml
120
What are cisterns and where are they?
```
Widened areas of the subarachnoid space
Quadrigeminal - above cerebellum
Prepontine
Cisterna magna - below cerebellum
Lumbar
```
121
What pathway does the CSF follow once it has left the ventricles?
Flows through subarachnoid space
Some CSF travels to lumbar cistern
Travels to arachnoid granulations for absorption into venous sinus blood
Granulations also sit around spinal nerves
122
What are arachnoid granulations?
Project into the superior sagittal sinus
| permit a one-way flow of CSF
123
How can meningitis lead to increased ICP?
Block arachnoid granulations
124
Describe the difference between a communicating and non communicating hydrocephalus
Communicating - blockage of arachnoid granulations
| Non communicating - blockage of cerebral aqueduct, CSF can't get out of ventricles
125
What does damage to the superior temporal gyrus result in?
Injury leads to inability to recognise sounds e.g. Speech vs. a door opening
126
What is the Posterior parietal cortex (superior lobule)? And what would damage here result in?
Integrates sensory inputs and controls perception of the contralateral environment/body
Damage can result in hemi-spatial neglect, Most often seen following right-sided damage, Patients ignore the contralateral half of their world, Walk into objects in affected visual field
127
What is Achromatopsia?
Inability to recognise colours
128
What is Prosopagnosia?
Inability to recognise faces
129
Where are Facial, shape and colour recognition cortices located?
medial occpital lobe
| Right side dominant
130
What is Associative agnosia?
perceives object but does not recognise
| Damage to visual association cortices
131
What can damage to the Frontal eye field?
Eye deviation toward damaged side
132
What is Dysphasia/Aphasia?
Defect of power of expression by speech or of comprehending spoken and written language
133
What is a Broca's dysphasia?
Motor speech - Content correct, but slow or missing words
134
What is Wernickes dysphasia?
Receptive aphasia (auditory & reading) Content incorrect, but speech fluent
135
What would a Angular gyrus lesion dysphasia present like?
Alexia / agraphia (inability to read or write)
136
What would a lesion to 1° Auditory cortex present like?
Reduction of hearing sensitivity in both ears (mostly contralateral) & loss of stereo perception of sound origin
137
Which side of the brain usually controls speech and language?
Left
138
What would damage to the arcuate fasciculus result in?
Conductive aphasia
Fluent dysphasic speech
Understands spoken and written word
139
What would damage to the corpus callosum result in?
Inability to name objects held in left hand
| Inability to read via left half of visual fields
140
What 4 ways can the arterial supply to the CNS be compromised?
Vessel occlusion – embolus or thrombus
Haemorrhage – burst aneurysm, degeneration of vessel wall
Aneurysm – often at sites of branching
Blocked venous drainage
141
Where does the internal carotid branch off the common carotid?
C3-4
142
Where do the vertebral arteries arise from?
Branches of subclavian artery
Pass up foramen transversarium & enter skull via foramen magnum
Supply the brainstem, cerebellum proximal spinal cord and posterior and inferior parts of the cerebral hemispheres
143
Which territories are supplied by the carotid circulation?
ACA and MCA - anterior circulation
144
What is the blood supply to the internal capsule?
medial & lateral striate arteries & anterior choroidal artery
145
What is the limbic system involved with?
Sensations of emotion
Visceral responses to emotion
Memories
146
Where is the limbic system ?
Made up from a rim of cortex: includes hippocampus & insula
Subcortical nuclei: amygdala, accumbens, septal, hypothalamic
Receives multiple inputs & provides multiple outputs
147
What is Papez circuit?
hippocampal formation → fornix → mammillary bodies → mammillothalamic tract → anterior thalamic nucleus → cingulum → entorhinal cortex → hippocampal formation
148
Where is the hippocampus?
Inferiomedial temporal lobe
| Associated with inferior horn of lateral ventricle
149
What does damage to the hippocampus produce?
Anterograde amnesia
No new memory formation
Patients are often be able to recall long term memories
Hippocampus also involved in memories involving spatial/ visuo-spatial tasks
150
What is Korsakoff’s Psychosis?
Metabolic damage / alcohol abuse
Mamillary and anterior thalamic damage, thiamine (B1) deficiency
Anterograde amnesia & often retrograde amnesia
Patients insert fabricated ‘memories’ of long term events into current
conversation (confabulation)
Werickne-Korsakoff syndrome – Above + Ataxia, opthalmoplegia &
dementia
151
What is the cingulate gyrus?
Cortical part of Papez circuit (limbic function)
Autonomic area: cardiorespiratoty & digestion, visceral response to emotions
Functions in emotional modulation of pain
Bladder control; Visual searching (for object)
Vocal area controlling appropriate sentence construction
152
What emotional response is the Amygdala responsible for?
```
Fear
Anger
Behavioural emotions
Impulsivity
Sexual behaviour & emotions
```
153
What can stimulation of the Amygdala cause?
```
Increase HR & BP
Reduce saliva
Increase GI motility
Cause irritability
Startle easily
Increase muscle tension
Cause pupil dilation
```
154
What area is involved in recognising emotional content of facial expression?
Amygdala
155
What is Kluver-Bucy Syndrome?
Bilateral damage to the amygdala
Docile, lack fear or anger
Increased appetite & hypersexual
Excess exploratory behaviour with mouth and hands
Visual agnosia
Memory disorders: lack of facial/object recognition
156
What are septal nuclei involved in?
Pleasure - sexual
157
What is the nucleus accumbens involved in?
Dopamine-activated reward centre
Intense sense of well being
Amphetamine & cocaine activate
158
What is the carotid sheath? Which structures lie inside it?
Membrane formed from the condensation of the cervical fascia, contains the internal carotid, internal jugular and vagus nerve
159
Which arteries supply the spinal cord?
Anterior spinal artery and posterior spinal arteries
160
The middle meningeal artery (which supplies the meninges) is a branch of which main artery? Where does it enter the skull?
The middle meningeal is a branch of External Carotid and enters the skull through the Foramen Spinosum
161
One of the first symptoms of intracranial haemorrhage is a ‘worst-ever’ headache. What nerves carry the sensory input from the meninges?
The cranial nerves carrying sensory info from the meninges are CNV (trigeminal), CNX (vagus) and a bit of CNIX (glossopharyngeal) and also cervical nerves 2 & 3 (C1 rarely has a sensory component)
162
What is the average blood flow in the brain (ml/100g/min)? How can you measure this?
60 ml/100g/min which can be measure by Doppler Ultrasound or Angiography
163
Name the deep veins that drain the corpus striatum, choroid plexuses and thalamus. Which main sinus do these drain into?
Thalamostriate, choroidal and internal cerebral veins, which drain into the great cerebral vein and into the straight sinus
164
Which main artery supplies the basal ganglia and internal capsule? What are the branches in this region known as?
The middle cerebral supplies the BG and IC and the branches are known as the Lenticulostriate arteries
165
The plexus of veins known as the cavernous sinus surrounds sections of which artery and cranial nerves? This sinus drains via two routes, what are they?
cavernous sinus surrounds the internal carotid and CNIII (oculomotor), CNIV (trochlear), CNV (trigeminal) and CNVI (abducens). It drains via the superior petrosal sinus into the transverse sinus or the inferior petrosal sinus into the internal jugular vein
166
Areas between the regions supplied by two adjacent cerebral arteries are most susceptible to ischaemia and infarction. What are these areas known as?
Watershed areas and infarcts are known as ‘Watershed infarcts’
167
What are the consequences of a blockage of a cerebral artery by an embolus?
Stroke – ischemic death of regions supplied by the artery, effects depend on area damaged
168
Define (a) ischaemic and (b) haemorrhagic stroke
a) Caused by blockage of a cerebral artery
| b) Damage caused by leaking of blood within or around the brain
169
What type of blood (arterial, venous, mixed) characterises Epidural (Extradural) haemorrhage?
Arterial
170
What type of blood (arterial, venous, mixed) characterises a subdural haemorrhage?
Venous
171
What type of blood (arterial, venous, mixed) characterises a subarachnoid haemorrhage?
Mixed - arterial and venous
172
Which imaging procedure would be most useful in diagnosing an aneurysm in a cerebral artery?
CT scan
173
What type of intracranial haemorrhage is most likely to result from a blow on the chin?
A blow to the chin generally Contrecoup injury when the brain rebounds from the blow, usually resulting in subdural haemorrhage
174
Can a cerebral infarct raise intracranial pressure sufficient to produce coning?
Yes, if it reaches >15mm Hg, e.g. swelling and coning of temporal lobe
175
What is diffusion weight imaging (DWI)? Following a stroke what is this technique useful for showing?
DWI is an MRI technique that maps the diffusion of water molecules in tissue. Useful for revealing ischemic damage and can reveal this far quicker that other MRI techniques following stroke
176
Which spinal nerves innervate the hand?
C6-8
177
Give 4 of the main signs used to distinguish upper and lower motor lesions
Pattern of weakness, pattern of wasting, plantar response, tendon reflexes, fasciculation (present/absent), tone of muscles, pain, sensory disturbance
178
What is the window for thrombolysis?
You have 4.5 hours post stroke to administer thrombolytics
179
What is the current recommended first line thrombolytics for ischaemic stroke?
Alteplase
180
Why would you expect an older person to respond more slowly to a haemorrhaging stroke than younger patients?
Cerebral atrophy is a natural part of the ageing process and as a result elderly patients have more available space to accommodate increases in volume from the bleed and would show a slower increase in intra-cranial pressure
181
What is a positive Romberg sign?
Instability when standing with eyes closed
182
What folds to form the neural tube?
Neural ectoderm
