Week 1 Flashcards
1
Q
What types of neuroglia are found in the CNS?
A
Ependymal cells
Oligodendrocytes
Astrocytes
Microglia
2
Q
What types of neuroglia are found in the PNS?
A
Satellite cells
Schwann cells
3
Q
What cells are responsible for producing myelin sheaths in the CNS and PNS?
A
CNS - oligodendrocytes
PNS - Schwann cells
4
Q
What is the function of microglia?
A
Macrophages
5
Q
What could be the underlying problem in a patient with RHS hemiparesis sparing the leg and aphasia?
A
Lesion of the LHS of the brain caused by stroke affecting the left middle cerebral artery causing damage to Broca’s area
6
Q
What part of the brain controls voluntary movement and what feature is it adjacent to?
A
Motor cortex
Central sulcus
7
Q
What are the names of the 2 main speech areas in the brain and on which side are they located?
A
Broca’s and Wernicke’s areas
LHS
8
Q
What nerve is affected in carpal tunnel syndrome?
A
Median nerve
9
Q
What is a possible cause of sensory loss following a ‘stocking and glove’ distribution?
A
Vitamin B12 deficiency
10
Q
Where do sympathetic preganglionic neurons originate from?
A
Thoracolumbar (T1-L3)
11
Q
Where do parasympathetic preganglionic neurons originate from?
A
Brainstem (cranial nerves)
Sacral (S2-S4)
12
Q
Where are sympathetic and parasympathetic ganglia located?
A
Sympathetic - in the sympathetic chain next to the vertebral column (far from target organ)
Parasympathetic - in the walls of the viscera which they innervate (close to target organ)
13
Q
How is the spinal cord organised?
A
31 segments
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
14
Q
What is the difference between passage of spinal nerves C1-7 and the rest?
A
C1-7 pass above their corresponding vertebrae
C8 onwards pass below
15
Q
What is the upper limit of the spinal cord?
A
Junction with medulla oblongata
16
Q
What is the lower limit of the spinal cord?
A
Newborn - L3/L4
Adult - L1/L2
17
Q
What does the alar plate become after development?
A
Dorsal horn
Receives incoming sensory information
18
Q
What does the alar plate become after development?
A
Ventral horn
Source of outgoing motor information
19
Q
What are the types of spina bifida by increasing severity?
A
Occulta
Lipomeningocele
Meningocele
Myelomeningocele
20
Q
What are the components of grey matter?
A
Dorsal horn
Intermediate horn
Ventral horn
21
Q
What are the components of white matter?
A
Dorsal funiculus
Lateral funiculus
Ventral funiculus
22
Q
In which spinal cord segments is the grey matter more predominant and why?
A
Cervical and lumbar
Innervation of limbs requires more fine sensory and motor innervation
23
Q
In which spinal cord segments is the grey matter less predominant and why?
A
Thoracic and sacral
Innervation of large coarse muscle groups requires little sensory and motor innervation
24
Q
Name the 3 layers of the meninges
A
Dura mater
Arachnoid mater
Pia mater
25
What are the main features of the dura mater?
Thick, inelastic membrane
| Fuses with endosteum of cranium at foramen magnum
26
What separates the dura mater from the vertebrae?
Epidural space
27
What are the main features of the arachnoid mater?
Thin, fibrous membrane
| Trabeculae formed across the arachnoid space
28
What is found within the arachnoid space?
Arachnoid trabeculae
| CSF (140ml)
29
What is CSF and where is it formed and reabsorbed?
Filtrate of blood
Formed - choroid plexus of ventricular system (500ml/day)
Reabsorbed - venous drainage system of the head
30
What is the function of CSF?
Mechanical and immunological protection for the brain and spinal cord
31
What are the main features of the pia mater?
Unicellular membrane
| Forms 21 lateral denticulate ligaments
32
What separates the pia mater from the spinal cord?
Very little
| Subpial space
33
What venous system is found in the epidural space and what is it's clinical significance?
Batson/vertebral venous plexus
| Major route of cancer spread from deep pelvic regions
34
What is the blood supply to the thoracic spinal cord?
Aorta → intercostal arteries → anterior spinal artery and 2 posterior spinal arteries
35
What is the artery of Adamkiewicz and what is it's clinical significance?
Arises from left posterior intercostal artery (70%) and supplies lower 1/3 of the spinal cord
Affected in anterior spinal artery syndrome - loss of continence and impaired leg function; complication of aortic aneurysm surgery
36
What is the tip of the end of the spinal cord called?
Conus medullaris
37
What are the loose strands at the end of the spinal cord called?
Cauda equina
38
What are filum terminale?
Filaments which anchor the end of the spinal cord in place
39
What is the lumbar cistern?
Site for epidural injections and lumbar puncture
40
How is an epidural injection performed?
L3/L4 or L4/L5 vertebral level
| Needle pushed into the epidural space
41
How is a lumbar puncture performed?
L3/L4 or L4/L5 vertebral level
| Needle pushed into spinal canal
42
What are lumbar punctures used for?
Withdraw CSF or measure pressure
| Administer antibiotics or chemotherapy
43
In which area of the spinal cord does the sensory aspect of the pain pathway terminate?
Superficial dorsal horn
44
In which area of the spinal cord does the sensory aspect of the gentle touch pathway terminate?
Deep dorsal horn
45
What is the diameter, speed and sensory receptor associated with Aα axons?
Diameter - 13-20 μm
Speed - 80-120 m/sec
Receptor - skeletal muscle proprioceptors
46
What is the diameter, speed and sensory receptor associated with Aβ axons?
Diameter - 6-12 μm
Speed - 35-75 m/sec
Receptor - skin mechanoreceptors
47
What is the diameter, speed and sensory receptor associated with Aδ axons?
Diameter - 1-5 μm
Speed - 5-30 m/sec
Receptor - pain, temperature
48
What is the diameter, speed and sensory receptor associated with C axons?
Diameter - 0.2-1/5 μm
Speed - 0.5-2 m/sec
Receptor - pain, temperature, itch
49
What ascending sensory pathways are there?
Discriminative touch - dorsal column medial lemniscus pathway
Pain - spinothalamic pathway
50
What descending activity modulating pathways are there?
Motor/voluntary - corticospinal and corticobulbar tracts
| Motor/muscle tone - reticulospinal, tectospinal, vestibulospinal
51
At what level do axons in the dorsal column medial lemniscus pathway cross over?
Secondary to tertiary neuron
52
At what level do axons in the spinothalamic pathway cross over?
Primary to secondary neuron
53
What is the typical resting membrane potential of a neuron?
-70mV
54
What is the distribution of Na, K and Cl across the membrane of a neuron?
Na - extra 145mM, intra 12mM
K - extra 5mM, intra 150mM
Cl - extra 110mM, intra 10mM
55
What is the equilibrium potential?
The membrane potential at which there is no net gain or loss of ions - electrical and chemical gradients are balanced
56
What is responsible for depolarisation and re/hyperpolarisation?
Depolarisation - fast opening of voltage gated Na channels
| Re/hyperpolarisation - slow opening of voltage gated K channels
57
How can voltage gated Na channels be used in medicine?
```
Lidocaine (local anaesthetic)
Nociceptive nerves (pain)
Epilepsy
```
58
What factors contribute to the passage of an electrical current through an axon?
Axon diameter
| Number of open channels
59
What is saltatory conduction?
The way action potentials jump from one node of Ranvier to the next in a myelinated axon
60
What disorders are associated with defective myelination of the CNS and PNS?
CNS - MS
| PNS - Guillain-Barre
61
What are the pathophysiology and symptoms of MS?
Antibodies attack myelin causing scar formation which delays/blocks action potentials
Symptoms - blurred vision, muscle pain, paralysis, fatigue, lack of co-ordination
62
What are the pathophysiology and symptoms of Guillain-Barre?
Inflammatory disease causing destruction of myelin
| Symtoms - progressive motor weakness, sensory and motor loss
63
What occurs at the postsynaptic terminal during neurotransmission?
Neurotransmitter causes channels to open to allow Na and Cl to enter
Ions cause depolarisation (excitation) or hyperpolarisation (inhibition)
64
What is an IPSP?
Inhibitory postsynaptic potential
Moves the post-synaptic membrane further away from threshold (hyperpolarised) to reduce the probability of the postsynaptic cell producing an action potential
65
What are temporal and spatial summation?
Temporal - multiple action potentials fired by the same axon (frequency)
Spatial - multiple action potentials fired by multiple axons
66
In what 2 ways can cholinergic synaptic transmission be disrupted?
Botulism - botulinum toxin from clostridium bacteria prevents ACh release leading to skeletal muscle weakness and diaphragm paralysis
Myasthenia gravis - antibodies bind to ACh receptors in postsynaptic membrane leading to muscle weakness
67
In what 2 patterns can information be spread within the nervous system?
Divergence
| Convergence
68
What methods are available for investigating cerebral function?
EEG
PET
fMRI
TMS
69
What is EEG and how is it used for cerebral function?
Electroencephalography
Records the electrical activity of
the brain
Investigate cognitive processes in response to a stimulus
70
What is PET?
Positron emission tomography
Measures blood flow, via a small dose of radioactive material injected into bloodstream
Locate brain activity while performing a task
71
What is fMRI?
```
Functional magnetic
resonance imaging
Measures blood
flow
Locate brain activity while performing a task
```
72
What is TMS?
Transcranial
magnetic
stimulation
Uses electromagnet to stimulate brain activity, causing depolarisation or interrupted firing
Interrupt brain activity while performing a task
73
Where are the 1st, 2nd and 3rd neurons usually located in a sensory pathway?
1st - periphery
2nd - CNS
3rd - thalamus
74
Briefly describe the route of the 1st neuron in the dorsal column medial lemniscal pathway
Aβ fibre
From periphery to lumbar spinal cord
Bifurcates into central and ascending branches (dorsal funiculus/column)
Projects upwards and terminates at gracile nucleus of the medulla
75
Briefly describe the route of the 2nd neuron in the dorsal column medial lemniscal pathway
Decussation at level of the brainstem
Continues as internal arcuate fibres
Projects upwards through medial lemniscus
Terminates at the VPL of the thalamus
76
Briefly describe the route of the 3rd neuron in the dorsal column medial lemniscal pathway
Travels via the internal capsule
| Projects to and terminates at the sensory cortex
77
What is the dorsal column medial lemniscal pathway responsible for?
Discriminitive tactile sensation
78
What is the spinothalamic pathway responsible for?
Pain, temperature, itch sensation
79
Briefly describe the route of the 1st neuron in the spinothalamic pathway
Aδ or C fibres
| Travels to and terminates at dorsal horn of lumbar spinal cord
80
Briefly describe the route of the 2nd neuron in the spinothalamic pathway
Decussation at level of the spinal cord
| Projects upwards in antero-lateral funiculus to the thalamus (branches given off at various points)
81
Briefly describe the route of the 3rd neuron in the spinothalamic pathway
Travels via the internal capsule
| Terminates at the sensory cortex
82
What is the difference between the corticospinal and corticobulbar pathways?
Corticospinal - axons from primary motor cortex project to motor nuclei in spinal cord
Corticobulbar - axons from primary motor cortex project to cranial nerve nuclei in the brainstem
83
What percentage of axons project in the lateral corticospinal tract compared to the anterior?
Lateral - 85%
| Anterior - 15%
84
What name is often given to the descending corticospinal/corticobulbar tracts?
Pyramidal tracts
85
Where does decussation occur in the corticospinal/corticobulbar tracts?
At the pyramids of the medulla
86
What are the lobes of the brain/bones of the skull?
Frontal
Parietal
Occipital
Temporal
87
What is the weight of an average brain?
1.3-1.4kg
88
Where are the cell bodies of axons in the corticospinal/corticobulbar tracts found?
Primary motor cortex
89
What are sulci and gyri?
Sulci - grooves
| Gyri - folds
90
What is the function of the precentral and postcentral gyri?
Pre - motor
| Post - sensory
91
How many temporal gyri are there and what are they called?
3
| Superior, middle, inferior
92
What does the central sulcus divide?
Frontal and parietal lobes
93
What important brain areas are located on the LHS?
Visual cortex
Auditory cortex - Wernicke's area
Motor speech - Broca's area
94
What is Broca's area and what is the consequence of damage to it?
Responsible for motor aspect of speech
| Damage - expressive aphasia, non-fluent, slow speech
95
What is Wernicke's area and what is the consequence of damage to it?
Sensory language area for lexical processing/understanding of speech
Damage - receptive aphasia, poor comprehension
96
What components make up the basal ganglia?
Caudate nucleus
Leniform nucleus - putamen and globus pallidus
Thalamus
Substantia nigra
97
What are the 3 main action selection centres of the brain which influence motor control?
Corpus striatum
Sub-thalamic nuclei
Substantia nigra
98
What basal ganglia comprise the corpus striatum?
Caudate nucleus
| Lentiform nucleus - putamen and globus pallidus
99
What disease results from damage to the substantia nigra?
Parkinson's disease
100
What disease results from damage to the corpus striatum?
Huntington's disease
101
What brain areas are affected in Parkinson's and Huntington's diseases?
Parkinson's - substantia nigra
| Huntington's - corpus striatum
102
What components make up the ventricular system of the brain?
```
Lateral ventricles (2)
Cerebral aqueduct
Third ventrical
Interventricular foramen
Fourth ventricle
```
103
What are the 4 areas of the corpus callosum called?
Rostrum
Genu
Body
Splenium
104
What group of cells produce CSF?
Choroid plexus
105
How is the internal capsule somatotopic?
Corticobulbar axons concentrated at the genu
| Corticospinal axons concentrated at the Posterior limb
106
What are the boundaries of the lentiform nucleus?
Claustrum
Posterior limb
Genu
Anterior limb
107
How many cranial nerves are there?
12
108
What are the cranial nerves?
```
Olfactory
Optic
Occulomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Vagus
Accessory
Hypoglossal
```
109
What is the basic anatomical layout of the circle of Willis?
2 vertebral arteries join to form the basilar artery
| Basilar artery joins several arteries to form a ring - posterior, middle and anterior cerebral arteries
110
What is the definition of pain?
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
111
What is involved in the acute catabolic stress response?
CNS - anxiety, depression, sleep deprivation
CVS - increased BP/HR/IHD
Respiration - inhibits cough, hyperventilation
GI - ileus, nausea, vomiting
GUS - urinary retention, uterine inhibition
Muscle - restless, immobility
Metabolic - increased cortisol/glucagon/GH/catecholamines, decreased insulin/testosterone/plasminogen (DVT)
112
What is nociception?
The neural mechanism by which an individual dectects the presence of a potentially tissue-harming stimulus
113
What are the processes involve in the nociception pathway?
Transduction, transmission, modulation, perception
114
How is pain/temperature sensed in the skin?
Free nerve endings - mechanical, thermal and chemical stimuli
115
What do Merkel's discs relay?
Touch
116
What do Meissner's corpuscles relay?
Touch
117
What do Pacinian corpuscles relay?
Vibration
118
What do Ruffini's endings relay?
Stretch
119
Where are nociceptors located?
Skin, bone, muscle, organs, blood vessels
| Not the brain
120
Outline the characteristics of Aδ fibres involved in pain
```
Fast
Physiological
High threshold
Thermo/mechanoreceptors
Sharp, short, localised pain
Reflex withdrawal
Not abolished by morphine
Useful for survival
```
121
Outline the characteristics of C fibres involved in pain
```
Slow
Pathophysiology
High threshold
Polymodal
Dull, diffuse, prolonged pain
Spasms and guarding
Abolished by morphine
Not useful
```
122
In what level of the dorsal horn do Aδ and C fibres enter?
Superficial laminae - I and II
123
In what level of the dorsal horn do Aβ fibres enter?
Deep laminae - III and VI
| Also feed into lamina II
124
What additional neurons are present in lamina II?
Interneurons - excitatory (glutamine) and inhibitory (GABA)
125
At what 2 levels is pain modulated?
Spinal - gate control theory (ascending)
| Supraspinal - conditioned pain modulation (descending)
126
Outline the gate control theory?
C fibre input absent - inhibitory interneurons block pain pathway
C fibre input - inhibitory interneurons blocked, painful stimulus sent to brain
C fibre and Aβ fibre input - inhibitory interneurons activated, painful stimulus to brain dereased (modulation)
127
What machine is used to block pain and also proves the gate control theory?
TENS - transcutaneous electrical nerve stimulation
128
Where do the fibres involved in descening modulation (supraspinal) arise?
Midbrain - periaqueductal grey matter (endogenous opioid receptors)
129
What neurotransmitters are involved in conditioned pain modulation and which is most useful in blocking pain?
Noradrenaline - most useful
| 5-HT
130
What is the core network of the supraspinal pain neuromatrix?
Sensory discriminative (site, severity, duration of pain) - thalamus, SS1, SS2, post insula
Affective-motivational - anterior insula cortex, anterior mid cingulate cortex
Cognitive activation - lateral prefrontal cortex
131
Define hyperalgesia
Abnormally high levels of pain from noxious stimuli (e.g. blunt pin-prick)
132
Define allodynia
Pain from a stimulus which is not normally painful (e.g. cotton wool)
133
Outline chronic pain hypersensitivity
Peripheral sensitisation - primary hyperalgesia
| Central sensitisation - secondary hyperalgesia and allodynia
134
What substances can activate nociceptors?
```
K+
5-HT
Bradykinin
H+
Histamine
ATP
Adenosine
```
135
What substances can sensitise nociceptors?
```
Prostaglandins
Leukotrienes
Substance P
Noradrenaline
Neurokinin A
CGRP
NO
ROS
```
136
What is the basic mechanism of peripheral sensitisation?
Nociceptors change from high threshold to low threshold due to influx of inflammatory cells
137
What is the basic mechanism of central sensitisation?
Loss of interneuron brake leads to hypo-active CPM
138
How can pain be classified?
Acute vs chronic (>3 months)
Cancer vs non-cancer
Nociceptive vs neuropathic
139
What is the difference between neuropathic and nociceptive pain?
Neuro - nerve damage (e.g. peripheral diabetic neuropathy)
Noci - tissue damage (e.g. RA)
Trauma/surgery constitutes a combination of both
140
How can nociceptive pain be divided?
Somatic - skin/muscle/bone
| Visceral - internal organs
141
What are the characteristics of somatic pain?
```
Well localised
Dermatomal
Sharp, aching, gnawing
Constant
Rarely associated
```
142
What are the characteristics of visceral pain?
```
Vague distribution
Diffuse
Dull, cramp, dragging
Periodic
Associated with nausea, sweating, HR and BP
```
143
What descriptors are associated with neuropathic pain?
```
Shooting
Electric-shock
Burning
Tingling
Numbness
```
144
How might a herniated intervertebral disc cause lower back pain?
Nucleus pulposus bulges out
Nociceptive pain - activation of local nociceptors (constant ache/throbbing of back)
Neuropathic pain - compression an inflammation of nerve root (shooting/burning of foot)
145
What are the 2 components of intervertebral discs?
Inner nucleus pulposus
| Outer annulus fibrosis
146
What is sciatica?
Herniated disc with lumbar radicular pain travelling all down the leg in a narrow band
147
What must sciatic pain be distinguished from?
Somatic referred pain due to noxious stimulation of interspinous ligaments at L3-S1 (particularly L5)
148
How are sciatic pain and somatic referred pain distinguished clinically?
Below the knee
Character of pain
Associated sensory/motor deficits
Aggravation by straight leg raise
149
How can severity of pain be assessed?
Numerical rating, verbal rating, visual analogue
Assess physical and mental impact and quality of life
30% improvement is good - manage expectations
150
What are the main associations of functional impairment?
Sleep disturbance, pain, anxiety and depression
151
What factors are important in pain?
Biomedical
Psychosocial
Affective-cognitive
Ethno-cultural
152
What is a brief pain inventory (BPI)?
Tool for assessing pain
Pain severity - 0-10, average/worst/least/now
Functional impairment - walking, work, sleep, mood, life, social
Can also be used to assess response to pain relief - increased function with decreased pain
153
What are the 6 P's of pain treatment?
```
Prevention
Pathology
Physical therapy
Pharmacotherapy
Procedures
Psychology
```
154
Outline the WHO analgesic ladder
Step 1 - non-opioids; paracetamol, NSAIDs
Step 2 - mild opioids; codeine, dextropropoxyhene
Intermediate - tramadol
Step 3 - opioids; morphine, oxycodone, fentanyl, methadone, pethidine
155
How is codeine metabolised in the body?
Pro-drug is metabolised to morphine by CP450 CYP 2D (significant genetic variation)
156
How is opioid prescribing decided on?
Pain - ensure type of pain is opioid-responsive
Patient - screen for dependency risk and monitor for abuse, define and agree on outcome
Prescription - drug, dose, duration
157
What pharmacologic therapies are used in neuropathic pain?
Anti-depressants - amitriptyline
Anti-convulsants - gabapentin, pregabalin
Anti-arrythmics - lidocaine
Others - ketamine, capsaicin, clonidine, cannabinoids
158
What are the 4 P's of harmful beliefs patients have with pain?
Progressive pathology
Passive - sickness behaviour, lack of support
DePression
Problems - social, work, financial, legal
159
What is the role of psychology in pain management?
```
Clinical explanation
Education class
Support groups
Pain management programme
1:1 psychology (or psychiatry)
```
160
What are the anatomical boundaries of lower back pain?
Tension, pain and/or stiffness posteriorly between ribs and inferior buttocks
161
What are the red flags associated with lower back pain?
```
Weight loss/past malignancy
Fever
Systemic inflammation
Anatomical change
History of trauma
Cauda equina syndrome
Neurological signs
```
162
What procedures may be used in lower back pain?
Epidural injection of steroid to reduce pain - temporary, expensive
Facet joint nerve denervation - medial branch of dorsal primary ramus, no associated problems
163
What is the STarT back screening tool?
9 questions to find out what the patient thinks of their pain, how they behave and what their expectations are
Low score = low risk chronicity, 2 days bed rest with paracetamol and some physiotherapy advice
High score = proactive, intense psychology and physiotherapy
164
What important structures are located at the root of the neck?
```
Apex of the lung
Stellate ganglion
Ventral rami of C8 and T1
Inferior trunk of the brachial plexus
Sublavian artery and vein
```
165
What are the roots of the brachial plexus?
C5, C6, C7, C8, T1
166
What are the trunks of the brachial plexus?
Superior, middle, inferior
167
What are the divisions of the brachial plexus?
Anterior, posterior
168
What are the cords of the brachial plexus?
Lateral, posterior, medial
169
What are the branches of the brachial plexus?
```
Musculocutaneous
Axillary
Median
Radial
Ulnar
```
170
Which dermatome relates to the inner aspect of the arm?
T1
171
What is Horner's syndrome?
Interruption of the sympathetic nerve supply to the eye, characterised by the classic triad of miosis (constricted pupil), partial ptosis (drooping upper eyelid), and loss of hemifacial sweating (anhidrosis)
172
Outline the 3 neuron arc involved in sympathetic innervation to the eye
1. Hypothalamus → spinal cord (C8-T2)
2. T1 → sympathetic chain → superior cervical ganglion → alongside internal carotid
3. Cavernous sinus → join abducens nerve → enter orbit with trigeminal nerve as long ciliary nerves → innervation of iris dilator and eyelid muscle contractor
173
Which neuron is most likely to be damaged by a Pancoast tumour to cause Horner's syndrome?
Second order neuron
174
What is a Pancoast tumour?
Cancer that form at the extreme apex of either lung in the superior sulcus and invade surrounding structures
175
What structures are at risk of invasion by a Pancoast tumour?
```
Lymphatics
Brachial plexus (inferior branch)
Intercostal nerves
Stellate ganglion
Sympathetic chain
Ribs
Vertebrae
```
176
What type of tumour are Pancoast tumours most likely to be?
Non-small cell lung cancer
| Squamous cell carcinoma
177
What are the risk factors for Pancoast tumours?
Smoking
Asbestos
Radon
Gold, nickel
178
What symptoms are associated with Pancoast tumours?
Radiating shoulder pain
Weakening/paraesthesia/atrophy of hand/arm muscles
Oedema
Horner's syndrome
179
How are Pancoast tumours diagnosed?
Chest x-ray
CT/MRI
Biopsy
180
How are Pancoast tumours treated?
Steroids
Pain management
Chemotherapy and radiation
Surgical resection
181
Which vertebra is the axis?
C2
182
Which vertebra is the atlas?
C1
183
What does C1 articulate with superiorly?
Occipital condyles of the skull
184
Why might osteoarthritis of facet joints in the cervical spine present as upper limb pain?
Nerve compression
185
Where is an emergency airway placed?
Cricothyroidotomy - between the thyroid and cricoid cartilages
186
How many cervical vertebrae are there?
7
187
How many cervical spinal nerves are there?
8
188
Why would laxity of the alar and dens transverse ligament be dangerous?
Dens may tilt back and crush the spinal cord
189
How are the external and internal carotid arteries distinguished anatomically?
Cannot depend on their relative location
External - larger, lots of branches
Internal - presence of sinus (bulge), no branches
190
At what vertebral level does the trachea start and end?
C6-T4
191
Explain the innervation of the eyelid
Smooth muscle - sympathetic
| Skeletal muscle - 3rd cranial nerve (occulomotor)
192
What conditions may cause distension of the external jugular vein?
Heart failure
| Mass/tumour pressing on the subclavian
193
How far might infection of the retropharyngeal space travel?
Peritoneum and diaphragm
194
Where does the thoracic duct terminate?
Joins the subclavian and jugular veins where they form the inominate (brachiocephalic) vein
195
What is the function of the sternohyoid and omohyoid muscles?
Depress the hyoid bone
196
Which vein lies behind the clavicle lateral to the sternocleidomastoid?
Subclavian vein
197
Why can numbness of the inner arm correspond with weaknes of hand grip?
Myotome and dermatome of T1 - root injury
198
Which spinal tract carries information about pain and temperature?
Spinothalamic
199
Which artery supplies blood to the lower third of the spinal cord?
Major anterior medullary (segmental) artery
200
Which nerve sensitising/stimulating agent is relevant to the analgesic action of aspirin?
Prostaglandins
201
Between which vertebrae is the inferior end of the adult human spinal cord typically located?
L1-L2
202
From which early embryonic tissue is the adult cerebellum derived?
Metencephalon
203
Damage to which specific part of the brain results in Broca’s (expressive) aphasia in most patients?
Left inferior frontal gyrus
204
What are arachnoid granulations?
Villous projections of the arachnoid membrane into the dural sinuses that allow CSF to move from the subarachnoid space into the venous system
205
What are arachnoid trabeculae?
Delicate strands of connective tissue that loosely connect the arachnoid mater and the pia mater
206
What are the denticulate ligaments and how many of them are there?
Bilateral triangular lateral extensions of pia mater that anchor the spinal cord to the dura mater; 21 in total
