Formative Nuero

Question 1

A rigger falls from a platform and catches himself by his right hand on a beam. The traction ruptures T1 nerve root. What disability will result?

Answer 1

T1 is distributed to the intrinsic muscles of the hand; through the ulnar nerve. Sensory supply to the skin through T1 to the medial aspect of the arm and forearm will be affected.

Question 2

A drunk sleeps with his arm over a park bench and compresses his radial nerve on the posterior aspect of his humerus. What will be his symptoms on awakening?

Answer 2

This can be deduced from the knowledge that the radial nerve supplies the triceps; brachioradialis; supinatorand extensor muscles of the digits. It supplies sensation to the posterior arm and forearm; plus the lateral two thirds of the dorsum of the hand

Question 3

Identify the structures normally visible and palpable at the wrist.

Answer 3

On the flexor surface; flexor carpi radialis; palmaris longus; flexor digitorum superficialis and flexor carpi ulnaris are conspicuous cords. The relations of these landmarks to the arteries and nerves should be identified. On the lateral surface; the abductor pollicis longus; extensor pollicis brevis and extensor pollicis longus are seen.

Question 4

Describe the different types of nerve fibres

Answer 4

Group A fibres include the largest myelinated somatic afferent and efferent fibres and have the highest
conduction velocity.
Group B fibres are myelinated pre-ganglionic fibres
Group C fibres are thin; non-myelinated; visceral and somatic pain fibres

Question 5

Define the terms neurapraxia; neurotmesis and axonotmesis; and describe how they arise.

Answer 5

Neurapraxia is failure of conduction of a nerve in the absence of structural damage resulting in numbness;
tingling and weakness. It is usually caused by compression of the nerve.
Neurotmesis is the complete severance of a peripheral nerve and is associated with degeneration of the
nerve fibre distal to the point of severance and slow nerve regeneration.
Axonotmesis is the rupture of nerve fibres (axons) within an intact nerve sheath as a result of prolonged
pressure or crushing. It is followed by degeneration of the nerve beyond the point of rupture but the
prognosis for nerve regeneration is good.

Question 6

What principles underlie the rehabilitation by physiotherapists and occupational therapists of a patient with a nerve palsy which may recover in time?

Answer 6

The central principle is to maintain mobility: if the limb is neglected while waiting for regeneration; the stiffness
of joints due to capsule tightening may become so severe that mobility cannot be restored later; even though
the nerve has regenerated. OTs are skilled in application of splintage and other aids; which prevent
contractures and maximise function; as well as reorganising the environment and possibly the patient?s work
around their disability.

Question 7

What is the physiological function of the myotatic reflex?

Answer 7

Programmed movements; where the gamma efferent system sets muscle shortening velocity; holding a
position; where the gamma system sets muscle length; contracting when load increases to prevent sagging
under the load; setting muscle tone. Testing by doctors does not really qualify

Question 8

What is the nerve supply of muscle spindles?

Answer 8

Afferents from the mechanotransducer region at the centre of the fibres are large class I axons; with cell bodies 
in the dorsal root ganglia; central processes synapsing with the alpha motor neurones supplying extrafusal 
muscle fibres; efferents to the contractile elements of the spindle fibres are gamma motor fibres.

Question 9

Which of the following characterises C type nerve fibres?

a) Axons lying free in the interstitial space.
b) Axons lying on the surface of Schwann cells in the interstitial space.
c) Axons lying within grooves on the Schwann cells.
d) Axons with only a single layer of formed myelin from Schwann cells.
e) Axons with fewer than three layers of formed myelin from Schwann cells.

Answer 9

c) Axons lying within grooves on the Schwann cells.

Question 10

Which of the following cells are essentially the immune cells of the central nervous system and those 
that react most to inflammation?
a) Fibrous astrocytes
b) Oligodendroglia
c) Protoplasmic astrocytes
d) Microglia
e) Schwann cells

Answer 10

d) Microglia

Question 11

Which of the following statements is correct regarding the rising phase of an action potential in a
neuron?
a) The membrane potential becomes more negative during this phase.
b) There is an influx of Na? through the nongated ion channels.
c) Na? flows into the neuron through voltage-gated Na? channels.
d) K? flows into the neuron through the voltage-gated K?
channels.
e) Energy for influx of Na?is provided by the Na? K? pump.

Answer 11

c) Na? flows into the neuron through voltage-gated Na? channels

Question 12

A trauma surgeon is repairing an open fracture of the humerus. While reducing the humeral fracture;
she notes that the large nerve running within a groove around the humerus has been torn. What deficit is
the patient expected to have?
a) Inability to extend fingers with posterior forearm anaesthesia.
b) Inability to flex fingers with anteromedial forearm anaesthesia.
c) Ulnar claw with intrinsic hand weakness; dorsal hand anaesthesia.
d) Inability to adduct thumb with palmar anaesthesia.
e) Inability to flex elbow with lateral forearm anesthesia.

Answer 12

a) Inability to extend fingers with posterior forearm anaesthesia.

Question 13

4. A 60 year old man describes chronic weakness in abducting the left shoulder and left shoulder
   numbness. He does not have shoulder or back pain. The left deltoid appears wasted on examination; and
   sensation to pinprick of the left shoulder is decreased. He thinks that these problems began after he
   dislocated his shoulder four years ago. What is the most like cause?
   a) Left C6 radiculopathy
   b) Left C4 radiculopathy
   c) Left axillary nerve injury
   d) Left musculocutaneous nerve injury
   e) Left radial nerve injury

Answer 13

c) Left axillary nerve injury

Question 14

The cauda equina consists of
(a) A bundle of posterior roots of lumbar; sacral and coccygeal spinal nerves
(b) The filum terminale
(c) A bundle of anterior and posterior roots of lumbar sacra; and coccygeal spinal nerves
(d) A bundle of lumbar; sacral; and coccygeal spinal nerves and the filum terminale
(e) A bundle of anterior and posterior roots of lumbar; sacral and coccygeal spinal nerves and filum
terminale

Answer 14

(e) A bundle of anterior and posterior roots of lumbar; sacral and coccygeal spinal nerves and filum terminale

Question 15

Which sensory pathway carries light touch and proprioception?

a) Dorsal column
b) Vestibulospinal tract
c) Spinothalamic
d) Chorda tympani
e) Corticospinal tract

Answer 15

a) Dorsal column

Question 16

Which ONE of the following nerves would be expected to have the greatest conduction
velocity?
a) An unmyelinated pain fibre; 30cm long; 1?m in diameter
b) An unmyelinated interneuron; 5mm long; 0.8?m in diameter
c) An unmyelinated interneuron; 1mm long; 0.2?m in diameter
d) A myelinated motor fibre; 20cm long; 0.9?m in diameter
e) A myelinated sensory fibre; 10cm long; 0.8?m in diameter

Answer 16

d) A myelinated motor fibre; 20cm long; 0.9?m in diameter

Question 17

A 66 year old man was admitted to hospital after he reported that he couldn?t move his legs.
Neurological examination indicated that; not only did he lose motor functions in both of his legs;
but that he could not detect any sensation in either leg when probed with a safety pin. However;
he was aware of sensation in both legs when the neurologist applied tactile stimulation to them.
It was concluded that the patient suffered damage to the
a) Anterior half of both sides of the spinal cord at the lumbar level
b) Posterior half of both sides of the spinal cord at the lumbar level
c) Region surrounding the central canal of the lumbar cord
d) Left half of the cervical cord
e) Dorsal roots of the lower thoracic cord bilaterally

Answer 17

a) Anterior half of both sides of the spinal cord at the lumbar level

Question 18

During a routine neurological examination on a 28 year old man; a medical student gently taps
on the patellar tendon to activate the knee jerk; or quadriceps reflex. The resulting reflex is within
normal range. Which of the following receptors is activated in response to this stimulus?
a) Golgi tendon organ
b) Merkel cell complex
c) Muscle spindle
d) Pacinian corpuscle
e) Ruffini complex

Answer 18

c) Muscle spindle

Question 19

Which of the following would best describe a reflex?

a) A chronic discomfort experienced by the patient
b) A clearly specified localising sign
c) A poorly localised sensory input
d) A voluntary response to a specific sensory input
e) An involuntary response to specific sensory input

Answer 19

e) An involuntary response to specific sensory input

Question 20

Which of the following is a sign that would most likely be seen in a patient with a lower motor neuron lesion?

a) Hyperreflexia
b) Hypertonia
c) Muscle fasciculations
d) Muscle groups affected
e) Muscle spasticity

Answer 20

c) Muscle fasciculations

Question 21

describe the spinal nerve dermatomes of the lower limb.

Answer 21

An anatomical atlas or clinical skills text helps to check these. Some keys are: L1 ? groin; L3 ? medial thigh; L5 ? lateral leg; S1 ? sole of foot; S3 ? weight bearing aspect of the buttocks.

Question 22

Outline the anatomy of the pain pathways.

Answer 22

Nociceptors are ?bare nerve endings.? Afferents in A-delta and C fibres; cell bodies in dorsal root ganglion; synapse in dorsal horn especially substantia gelatinosa. Cross midline to ascend in the anterolateral spinothalamic tracts and synapse in the thalamus.

Question 23

How does somatic referred pain differ from radicular pain?

Answer 23

Somatic referred pain is usually dull; deep and aching. It is usually felt in the upper rather than lower
part of the leg and spreads from the lumbar spine. Radicular pain is typically lancinating in quality;
shooting down the leg like an electric shock. It affects a narrow band; is often made worse by coughing or sneezing; which raises intradiscal pressure; and may be associated with neurological signs due to nerve root compression. Importantly; lumbar radicular pain is not back pain but leg pain.

Question 24

A man suffers a crush injury to his vertebral column resulting in partial destruction of the spinal cord segments L1-L2. What will be the neurological deficit and clinical signs?

Answer 24

The key is that there is a lower motor neuron lesion (flaccid paralysis; wasting; no reflexes) in the myotomes corresponding to the crushed cord region. Below that region; if the cord is intact but disconnected from higher centres; there will be an upper motor neuron lesion (spastic paralysis and loss of sensation; exaggerated reflexes; tone; and preservation of muscle mass).

Question 25

A pituitary tumour commonly causes what visual field defect?

a) Bitemporal hemianopia
b) Homonymous hemianopia
c) Superior homonymous quadrantanopia
d) Complete loss of vision right eye
e) Arcuate field defect in one eye

Answer 25

a) Bitemporal hemianopia

Question 26

Which of the following is NOT part of the basal ganglia?

a) Caudate nucleus
b) Red nucleus
c) Subthalamic nucleus
d) Putamen
e) Substantia nigra

Answer 26

b) Red nucleus

Question 27

Damage to the primary visual cortex can produce?

a) Isolated achromatopsia
b) Blind sight
c) Optic ataxia
d) Apraxia
e) Hemi-neglect

Answer 27

b) Blind sight

Question 28

The only cranial nerves that are attached to the cerebrum are the __________ nerves.

a) Optic
b) Oculomotor
c) Trochlear
d) Olfactory
e) Abducens

Answer 28

d) Olfactory

Question 29

On examination of an elderly man?s palatal movements; you observe that when asked to say ?ah? that the left side of his palate is at a lower level than his right and that his uvula is deviated towards the right. You conclude that this patient most likely has suffered a lesion to his

a) Left glossopharyngeal nerve
b) Right glossopharyngeal nerve
c) Left vagus nerve
d) Right vagus nerve
e) Left spinal accessory nerve
f) Right spinal accessory nerve

Answer 29

c) Left vagus nerve

Question 30

Which one of the following statements regarding the Circle of Willis is correct?

a) It is the primary source of blood supply to the pons and medulla
b) It includes two vertebral arteries
c) It is the site where most of the cerebrospinal fluid is formed
d) The superior cerebellar artery arises from the circle of arteries
e) It surrounds the optic chiasm and the infundibulum of the pituitary

Answer 30

(e) It surrounds the optic chiasm and the infundibulum of the pituitary

Question 31

An 83 year old lady attended her general practitioner complaining of an inability to swallow

food. The structure in the medulla most closely linked to this dysfunction is
a) Inferior olivary nucleus
b) Pyramids
c) Spinal terminal nucleus
d) Nucleus ambiguus
e) Hypoglossal nucleus

Answer 31

d) Nucleus ambiguus

Question 32

A patient presents with double vision; drooping of the eyelid; dilation of the pupil; a downward abducted eye and inability to accommodate to a near object. You conclude that the patient has suffered damage to:

a) Cranial nerve II
b) Cranial nerve III
c) Cranial nerve IV
d) Cranial nerve V
e) Cranial nerve VI

Answer 32

b) Cranial nerve III

Question 33

During a routine examination; the doctor attempted to elicit a gag reflex response in the patient by stroking the posterior pharynx with a cotton-tipped probe. This reflex is initated primarily by activating the sensory endings of:

a) Cranial nerve V
b) Cranial nerve VII
c) Cranial nerve IX
d) Cranial nerve XI
e) Cranial Nerve XII

Answer 33

c) Cranial nerve IX

Question 34

Which one of the following statements is correct regarding photoreceptors?

a) Rods are specialised for day vision
b) Rods contain more photosensitive pigment than cones
c) Loss of cones in the retina causes night blindness
d) Cones outnumber rods
e) Rods are concentrated within the fovea

Answer 34

b) Rods contain more photosensitive pigment than cones

Question 35

During a routine physical examination; a 57 year old man is unable to successfully conduct a finger to nose test or a heel to shin test. These signs and symptoms would most likely indicated damage in which of the following brain regions?

a) Basal nuclei
b) Cerebellum
c) Motor cortex
d) Spinal cord
e) Thalamus

Answer 35

b) Cerebellum

Question 36

Sketch the arterial supply of the brain.

Answer 36

the answer needs to cover the layout of the vertebral arteries feeding the basilar artery; the circle of
Willis and posterior cerebrals: the internal carotids feeding the middle and anterior cerebrals and
the communicating arteries; which complete the circle. Then some major branches such as the
striate arteries should be identified.

Question 37

Which of the following is the amino acid precursor of the most prevalent excitatory neurotransmitter in the brain?

a) Glutamate
b) Glutamine
c) Aminobutyric acid
d) Tyrosine
e) Tryptophan

Answer 37

b) Glutamine

Question 38

Which of the following is the primary structure creating the blood-CSF barrier?

a) Choroid plexus
b) Modified cilia
c) Tight junctions
d) Arachnoid granulations
e) Arachnoid villi

Answer 38

c) Tight junctions

Question 39

A patient presents with receptive dysphasia. Where is the lesion most likely to be?

a) Cribiform plate
b) Striate cortex
c) Substantia gelatinosa
d) Wernicke?s area
e) Chorda tympani

Answer 39

d) Wernicke?s area

Question 40

What is the most likely clinical consequence of damage to the right posterior parietal cortex?

a) Muscle wasting
b) Ataxia
c) Apraxia
d) Aphasia
e) Sensory and visual inattention

Answer 40

e) Sensory and visual inattention

Question 41

What lesion causes muscle wasting with loss of reflexes?

a) UMN (upper motor neuron) b) LMN (lower motor neuron)
c) Cerebellar
d) Third nerve lesion
e) Total cord transection at C2

Answer 41

b) LMN (lower motor neuron)

Question 42

Considering a coronal section of the brain; which structure of the striatum is located most laterally?

a) Caudate
b) Putamen
c) Globus pallidus
d) Thalamus
e) Cerebral cortex

Answer 42

b) Putamen

Question 43

You evaluate a right handed patient with a suspected cortical infarction in the distribution of
the left middle cerebral artery. Which of the following is most likely to be spared?
a) Right-sided face motor function
b) Right-sided arm motor function
c) Right-sided leg motor function
d) Language repetition
e) Language fluency

Answer 43

c) Right-sided leg motor function

Question 44

You evaluate a patient whose right arm is markedly weak. Reflexes in the arm are decreased. \However; you note that reflexes are rather brisk in the right leg and the patient has an up-going toe on the right. Reflexes are normal on the left. What structure is involved?

a) Peripheral nerves
b) Ventral roots
c) Spinal cord
d) Brainstem
e) Alpha motor neurons

Answer 44

c) Spinal cord

Question 45

Damage to which structure may cause a deficit in memory?

a) Basal nucleus of Meynert
b) Substantia nigra
c) Mammillary bodies
d) Subthalamic nucleus
e) Right posterior parietal cortex

Answer 45

c) Mammillary bodies

Question 46

Mrs Brown aged 69 attends Neurology Outpatients with a history of loss of vision in her right eye lasting ten minutes two weeks ago. She has a 40 pack year smoking history. On examination she has 6/9 vision in both eyes; a normal neurological examination and a right carotid bruit. BP is 140/90 and ECG shows sinus rhythm at 80/minute. Carotid Doppler duplex study reveals 75% stenosis right ICA and 50% stenosis left ICA.
1. What vascular territory is involved?
2. What type of stroke lesion is it?
3. What is the likely cause?
4. What is the risk of death or recurrent stroke for this patient over the next twelve months;
twenty-four months?
5. What interventions have been shown to reduce the risk of death or stroke for this patient?

Answer 46

Ophthalmic artery
2. Transient ischaemic attack (TIA)
3. Embolus from right internal carotid artery
4. Risk of death about 8% in the first year; risk of recurrent stroke 12% in first year and 5% per
year thereafter.
5. Antiplatelet therapy (low dose aspirin +/- modified released dipyridamole or clopidogrel) should be prescribed to all people with stroke/TIA. This can lead to reduction in the risk of serious vascular events (stroke; myocardial infarction or vascular death) by 25% in patients with previous TIA. BP and cholesterol lowering medication should be prescribed. Carotid endarterectomy reduces the risk of ipsilateral stroke by 10-17% over 2 years; independent of antiplatelet therapy; in patients with 70-99% stenosis. Smoking is a risk factor for vascular events; particularly myocardial infarction; but also ischaemic stroke. Smoking cessation; improving diet; increasing exercise and avoiding excessive alcohol consumption are all behavioural measures that have a proven positive impact in stroke reduction.

Question 47

What mechanisms permit (partial) recovery in stroke?

Answer 47

Some of the initial impairment may have been due to ischaemia without infarction (death) of
neurons; or to pressure from swollen necrotic tissue or a haemorrhage nearby; and these may
reverse with time. Then there is plasticity; in which adjacent regions take over functions without
developing new connections; but by changing synaptic strengths and modifying lateral inhibition.
Finally; there is retraining and development of skills using the remaining functions to improve
mobility; in which the physiotherapy team is vital.

Question 48

List the risk factors for stroke.

Answer 48

Essentially; the risk factors for stroke are the same as those for the CVS; except that hypertension is 
particularly strongly associated. 
Risk factors for athero-thrombotic stroke
? Hypertension
? Age >65
? Hypercholesterolaemia
? Diabetes mellitus
? Smoking
? Family history of cerebrovascular events
? Obesity
? History of TIAs
? Involvement of other vascular territories; eg; ischaemic heart
disease; peripheral vascular disease
? Thrombophilic conditions
? Vasculitis
? Extracranial arterial dissection