Week 1 Flashcards
What bones make up the Neurocranium?
Frontal
Parietal x2
Occipital
Sphenoid
Temporal x2
Ethmoid
What bones make up the Viscerocranium?
Nasal x2
Palatine x2
Vomer
Maxilla x2
Mandible
Zygomatic x2
Lacrimal x2
Ethmoid
Name structures 1-5
1 - Pterion
2 - Zygomatic Arch
3 - Mastoid Process
4 - External Acoustic Meatus
5 - Mandibular Angle
Name the 3 suture lines
Coronal
Sagittal
Lambdoid
Name the 3 Structures
Groove for sup. sagittal sinus
Granular Foveolae (Arachnoid Granulations)
Grooves for middle meningeal arteries
What are Fontanelles and what is their purpose?
ant. and post. fontanelles are soft areas between the skulls bones after birth that allow the head to be easier pushed out during birth and for the skull to grow
What is the Pterion?
The H shaped suture point where the temporal, frontal, parietal and greater wings of sphenoid join
What would be a possible issue caused by trauma to the Pterion?
Haematoma
What nerves pass through the Sup. Orbital fissure?
Sup. + Inf. Oculomotor CN III (branches)
Trochlear CN IV
Abducens CN VI
Lacrimal n.
Frontal n.
Nasociliary n.
Sup. + Inf. ophthalmic vein
what structures pass through Inf. Orbital fissure?
Zygomatic branch of maxillary n.
Infra orbital n.
Inf. ophthalmic vein
What do the superior aspects of the temporalis muscle and its fascia attach to on the skull?
Temporalis - Inf. temporal line
Fascia - Sup. temporal line
Within what structure does the Facial CN VII branch?
Parotid Gland
What is the purpose of the Cribriform foramina?
Allow the Olfactory CN I bulbs to receive nerve fibres from Nasal cavity
What is the main symptom of a fractured cribriform plate?
CSF Rhinorrhoea
What is the function of the Sup. and Inf. articular cavities in the Temporomandibular joint (TMJ)?
Sup. allows sliding for initial opening
Inf. allows rotation for biting motion
Lateral ligament in the Temporomandibular joint (TMJ) prevents what?
Post. dislocation
What are the two major systems of descending pathways from cortex to motor centres?
Lateral Pathways & Ventromedial (Medial) Pathways
What’s the function of the lateral pathways?
Control voluntary movement
Control distal muscles
Mainly controlled by cerebral cortex
What is Apraxia?
Inability to perform complex sequence of movements (ie. brushing teeth, drawing sketch)
What is a potential cause of Apraxia?
Damage to premotor area of brain
What percentage of Corticospinal tract (CST) nerves are in the Lateral & Anterior CST respectively?
85% & 15%
Lateral tract nerves will decussate in the medulla where as the anterior will stay ipsilateral until they innervate bilaterally at level of their ventral root
What is the most common causes of lesions of corticospinal neurons?
Infarcts related to cerebrovascular incidents (particularly middle cerebral a.)
Trauma
Tumours
Demyelinating diseases
What is the difference between +ve and -ve signs of corticospinal neuron lesions?
+ve is the appearance of an abnormal response
-ve is the loss of function (weakness or paralysis)
Corticospinal lesions may give rise to what?
Upper motor neurone syndrome
What are the symptoms of Upper motor neurone syndrome?
Pyramidal muscle weakness (hemiparesis)
No muscle atrophy
No fasciculations
Increased muscle tone
Increased stretch reflexes
Abnormal reflexes
What are the symptoms of Lower motor neurone lesions?
Muscle weakness (lesion dependant)
Muscle atrophy
Fasciculations
Reduced muscle tone
Reduced stretch reflexes
What is the main function of the Ventromedial pathways?
Posture
What are the principal compensatory reflexes for Vestibular, Collicula, Reticular, and Tectal?
Body
Head / Body
Body
Head / Trunk
What are the functions of the Corpora Quadrigemina?
Controls position of head and eyes in response to visual, auditory and somatic stimuli
Also transmits auditory signals to auditory centre in brain
What are the pros and cons of a CT scan?
Fast & widely available however, produces ionising radiation
CT scans are taken in what plane?
Supraorbitomeatal plane
What 3 ways can an MRI be weighted?
T1, T2, or PD (proton density)
What is the benefit of a T1 weighted MRI?
Good for anatomy and contrast
How do substances appear on a T1 weighted MRI?
Water (CSF) is dark
Grey matter is dark grey
White matter is off-white
Fat is white
What is the benefit of a T2 weighted MRI?
Good for identifying pathology - inflammation, oedema
How do substances appear on a T2 weighted MRI?
Water is white
White matter is darker than grey mater
What benefit is there to Diffusion Weighted Imaging (DWI)?
Very good for detection of ischemia, infarct, and stroke
What may be done complimentary to a Diffusion Weighted Image?
Apparent Diffusion Coefficient (ADC)
Examples of MRI contraindication
Implanted metal devices
Foreign bodies (shrapnel)
Claustrophobia
What benefit is there to SPECT & PET?
Useful for identifying cancer, infection, coronary artery disease, brain disorders
What does the ABC’S system for interpreting Brain scans stand for?
Adequacy, Alignment, Artefact
Bones, Blood & Brain
CSF-filled spaces
Subcutaneous & surfaces, symmetry
What structure carries sensory info from the lower trunk and lower limbs in the spinal cord (below C6)?
Fasciculus Gracilis
What structure carries sensory info from the upper trunk and upper limbs in the spinal cord (above C6)?
Fasciculus Cuneatus
Where in the spinal cord are Fasciculi Gracilis and Cuneatus found?
Dorsal Column (medial & lateral respectively)
At what spinal & vertebral levels are the cervical and lumbar enlargements of the spinal cord?
Cervical
Spinal: C4 - T1
Vertebral: C4 - C7
Lumbar
Spinal: L2 - S3
Vertebral: T11 - T12
What is the function of the Clarke n. and at what levels is it present?
Relay for proprioceptive info traveling to the cerebellum, C8 - L3
What pathway does proprioceptive info going to the cerebellum take?
Below L3 travels in fasciculus gracilis, travels through Clarke nucleus to C8, moves through fasciculus cuneatus until they synapse in Cuneate nuc.
Modality of Meisner corpuscles?
Fine touch / light touch
Modality of hair follicle endings?
Touch
Modality of Merkel discs?
Pressure, low freq vibration
Modality of Pacinian corpuscles?
Vibrations
Modality of Ruffini endings?
Skin stretch, pressure
Modality of Nociceptors?
Pain
Modality of muscle spindles?
Muscles length / stretch
What is the benefit of lateral inhibition in sensory neurons?
Allows better discrimination of where a stimulus is located by inhibiting surrounding neurons
What information is carried in the dorsal and ventral spinocerebellar tracts?
Unconscious Proprioceptive info from muscle spindles and golgi organs
What information is transported in spinothalamic tracts?
Pain & temperature
Name the 3 principal ascending tract systems in the spinal cord
Spinothalamic, Spinocerebellar, Dorsal column-medial lemniscus
Where does the spinothalamic tract nerves cross over the mid line?
At the vertebral level it enters +/- 1 or 2 dermatomes
Where do the Medial lemniscus nerves cross over the midline?
After gracile/cuneate nuclei in brainstem
Where do the Spinocerebellar nerves cross over the midline?
They DON’T
What information is transported in the Dorsal column-medial lemniscus?
JPS, Conscious proprioception, Light touch, Vibration, Pressure
What is Astereognosis?
Inability to discriminate shape and size by touch and inability to recognise objects by touch
What is Amorphosynthesis?
No somatosensory info from one side of the body usually caused by a lesion in the left parietal lobe
What is a common symptom of a lesion in fasciculus Gracilus?
Gait problems
A lesion in fasciculus Cuneatus may cause motor problems in the arms but this can be minimised thanks to…
Vision allowing corrections of arm movement to be made
What is the difference in Aδ and C fibres?
Aδ detect Heat, cold, and sharp pain
C detect dull aching pain and itch
What 4 pathways make up the Anterolateral pathway?
Paleo-spinothalamic tract (thalamus)
Neo-spinothalamic tract (thalamus)
Spinomesencephalic tract (midbrain)
Spinoreticular tract (midbrain)
What would be the consequence of a lesion in the lateral spinothalamic tract?
Decreased perception of pain and temp on the contralateral side of the body 1 or 2 dermatomes below the lesion
Identify all structures
^^^
Why can LMN damage still lead to fasciculations when UMN damaged can’t?
In UMN lesions the LMN’s are still intact and still send out inhibitory signals to the muscles preventing fasciculations. In LMN lesions the muscles don’t receive inhibitory signals, therefore they only get excitatory signals leading to fasciculations
Function of Spinomesencephalic tract?
For descending pain modulation
Function of Spinoreticular tract
For arousal and other pain driven responses
Where does the Neo-spinothalamic tract synapse, and where does it project?
Synapses at the Ventral posterolateral lobe of the thalamus (VPL)
Projects to somatosensory cortex
Where does the Paleo-spinothalamic tract synapse, and where does it project?
Synapses at the Dorsal medial intralaminar section of the thalamus (DM)
Projects to limbic centres and memory
What is thought to be the most probable cause of depression?
Reduction in serotonin receptors in hippocampus
Serotonin levels themselves have little impact
What are MAOI (mono amine oxadase inhibitors)?
Inhibit MAO enzymes
MAO breaks down norepinephrine/serotonin and dopamine
Therefore inhibition causes all 3 levels to increase
Give an example of a MAOI and list some side effects
Phenelzine
Weakness, headache, weight gain, fatigue ect.
What can MAOI not be used in combination with?
SSRI/Tricyclic nor morphine/tramadol as will increase serotonin to dangerous levels (potentially death)
What foods shouldn’t be consumed when taking MAOI’s?
Foods high in tyramine ie.
Cheese
Venison
Alcohol
How do Tricyclic Antidepressants work?
Act by inhibiting re-uptake of norepinephrine and serotonin by blocking the transporters responsible for re-uptake of these neurotransmitters
Increases conc of neurotransmitters in the synapses, triggering further neurotransmission
What can Tricyclic antidepressants be used for?
Depression
Anxiety
Chronic pain
What are some of the side effects of Tricyclic antidepressants?
Risk of arrythmias
Reduced intestinal mobility
Urinary retention
Name some common Tricyclic antidepressants
Amitriptyline
Lofepramine
How do SSRI’s (selective serotonin re-uptake inhibitors) work?
Increase levels of neurotransmitter serotonin by limiting its re-absorption and pure SSRI have only weak affinity for norepinephrine and dopamine transmitters
What is the name for serotonin receptors?
5-HT receptors
What are some of the side effects of SSRI’s?
Sexual dysfunction + reduced libido
QT interval prolongation
Increased risk of GI bleeds
Increase risk of suicide (18-25 y/o can’t be prescribed SSRI’s)
Epilepsy
What other condition may present with similar symptoms to depression?
Hypothyroidism
What are 3rd line drug treatments for depression?
SNRI’s (serotonin norepinephrine re-uptake inhibitors)
Why are Tricyclic antidepressants effective in chronic pain management?
Have direct effect on the mechanisms of the pain pathway (blocking of pathway)
Give an example of a commonly used antidepressant for pain management
Amitriptyline
What should you check for in a patients drug history before prescribing antidepressants?
Any other drugs that may elongate the QT interval
Define Anhedonia
Loss of interest or pleasure in hobbies and activities that were once enjoyed
According to NICE guidelines, what are the key symptoms of depression?
Persistent sadness or low mood
and/or
Anhedonia
What are some risk factors for depression?
Genetics and family factors
Early life experiences
Stressful life events
Social support
Gender
What is the BEST treatment for depression?
Placebo
What structures pass through the Optic canals?
Optic n.
and
Ophthalmic a.
What structures pass through the Sup. Orbital Fissure?
CN V1, III, IV, VI
Sympathetic fibres
Ophthalmic veins (sup. + inf.)
What structures pass through the Inf. Orbital Fissure?
Infra Orbital n. v. and a.
Inf. Ophthalmic v.
Zygomatic n.
What structures pass through Foramen Rotundum?
CN V2
(Maxillary)
What structures pass through Foramen Ovale?
CN V3
(Mandibular)
and
Accessory meningeal a.
What structures pass through Foramen Spinosum?
Middle Meningeal a. and v.
Meningeal branch of CN V3
What structures pass through Foramen Lacerum?
Deep Petrosal n.
Meningeal a. branches and small veins
What structures pass through the Groove or Hiatus of Greater Petrosal n.?
Greater Petrosal n.
Petrosal branch of mid Meningeal a.
What structures pass through Foramen Magnum?
Medulla and Meninges
Vertebral a.
CN XI
Dural veins
ant. + post. Spinal a.
What structures pass through the Jugular Foramen?
CN IX, X, and XI
Sup. bulb of Int. Jugular v.
What structures pass through the Hypoglossal Canal?
Hypoglossal n.
CN XII
What structures pass through the Condylar Canal?
Emissary v. that passes from sigmoid sinus to vertebral veins in neck
What structures pass through the Mastoid Foramen?
Mastoid emissary v. from sigmoid sinus
Meningeal branch of Occipital a.
Name the structures
^^^
What are the 2 Extrinsic and 1 Intrinsic ligaments of the Temporomandibular Joint (TMJ)?
Extrinsic:
Sphenomandibular lig
Stylomandibular lig
Intrinsic:
Lateral lig
Name the structures
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Name the structures
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Name the structures
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Name the structure
^^^
What 2 structures make up the intervertebral joints?
Intervertebral symphysis
and
Facet Joint
What happens in a whiplash injury?
Tearing of Interspinous ligaments and tearing in Facet joint capsules
