Neurological Flashcards
Pre/Post central gyrus are also known as ____ and are on either side of the ____
Primary sensory/motor cortex on either side of the central sulcus
The Cerebellum is mostly associated with what function?
Coordination
What two areas make up the Diencephalon?
The Thalamus and Hypothalamus
What is the name of the white matter area that divides the hemispheres?
Corpus Callosum
What are the areas that make up the Corpus Callosum?
Genu at front with rostrum underneath, body in middle, splenium at the back.
What connects the 3rd and 4th ventricle and where is it located?
The cerebral aqueduct is located between the cerebellum and the medulla/pons
What is the main split down the middle of the brain called?
Longitudinal fissure
The ends of the Hippocampus are called the ____ and are associated with ____
Amygdala, emotion, especially fear
Where is CSF made?
In the choroid plexus of the ventricles
Which 2 layers form the subarachnoid space?
Arachnoid mater and pia mater
What is the path of CSF?
Lateral ventricles > Interventricular foramen > 3rd ventricle > Cerebral aqueduct > 4th ventricle > apertures > subarachnoid space > arachnoid granulations > super sagittal sinus
In what way does the spine continue down to the coccyx?
The pia mater continues down as the filum terminale
What types of neurons are present in the dorsal root?
Sensory
What types of neurons are present in the ventral root?
Motor
How many segments in spinal column?
31
Which feature helps to orient the spinal column
The VENTRAL fissure
The dorsal horn of the spinal grey matter holds mostly ___ cell bodies
sensory
The ventral horn of the spinal grey matter holds mostly ___ cell bodies
lower motor
Which suture joins the frontal bone with the parietal bone?
Coronal suture
Which suture joins the parietal bones together?
Sagittal suture
Which suture joins the occipital bone to the parietal bones?
Lamboid suture (think Lambda)
Name of the weak point of the temporal skull where the 4 bones (temporal, sphenoid, parietal and frontal) meet.
Pterion
Which suture joins the parietal bones to the temporal bones?
Squamous sutures
Where does the pituitary sit in relation to skull bones?
In the saddle shaped hypophyseal fossa of the sphenoid bone
Name of the un-ossified connections in a baby’s skull that can show signs of dehydration or raised ICP
Fontanelles
Describe the dura mater
2 layers - periosteal and meningeal - the gap forms the dural venous sinuses
Which layer of the meninges is avascular?
Arachnoid mater
Where does all venous drainage of the brain end up?
Jugular vein
Describe the neurological homunculus.
Most medial: feet + legs
Most lateral: tongue and face
Which area of the brain is used for comprehension and where is it located?
Wernicke’s area, dominant temporal lobe.
Which area of the brain is used to control speech and ‘find’ words, where is it located?
Broca’s, dominant frontal lobe.
The internal carotids immediately become which arteries in the Circle of Willis?
Middle Cerebral Arteries
3 main causes of delirium:
infection (UTI), medications, metabolic disturbances such as vitamin deficiency
What causes Wernicke’s encephalopathy?
Vitamin B1 (Thiamine) deficiency - often due to alcoholism (need it for myelin).
Which two cell types make myelin?
CNS - oligodendrocytes PNS - Schwann Cells
What are the layers of the scalp?
S - skin
C - connective tissue
A - aponeurosis
L - loose connective tissue
P - periosteum
Which layer of the scalp houses the arteries?
Layer 2 - connective tissue
Name the main branch of the internal carotid associated with the face, and which two arteries it branches into to supply the forehead.
The ophthalmic artery which becomes the supraorbital and supratrochlear arteries - only arteries of the face from the internal carotid
What are the main muscles of the eye?
Orbicularis oculi is the main one and the supercilliary muscles are also there for eyebrow movements.
Which muscles control the lips and cheeks?
Orbicularis oris for the lips and buccinator for the cheeks
What are the muscles of mastication?
Masseter, temporalis, pterygoids x2.
Which two cranial nerves control the face?
CN 5 and 7, trigeminal and facial
Which vertebral segments innervate the back of the head?
C2 and C3
What are the 3 trigeminal divisions?
ophthalmic, maxillary, mandibular (only mixed one - for eating)
What does the facial nerve do and what are its branches?
Expressions (motor), divided into 5 after the parotid gland: The Zebra Bit My Cat.
Temporal, Zygomatic, Buccal, Mandibular, Cervical
Main artery of the face and its root?
The facial artery, from the external carotid.
What is special about the facial vein?
VALVELESS - infection risk.
Where does all face lymph end up?
Deep cervical lymph nodes
Difference between dysarthria and dysphasia?
Dysarthria is difficulty with the motor aspects of speech, dysphasia is difficulty with language.
Dysphasia can be split into which 2 broad types?
Broca’s - non-fluent with difficulty finding words but sensical
Wernicke’s - fluent with incorrect words (word salad) - non-sensical.
“Thunderclap headache” is a red flag for which presentation?
Subarachnoid haemorrhage.
What is Cushing’s Triad?
A triad of symptoms present during raised ICP (HYPER BRADY BRADY) - HTN, bradypnea, bradycardia
How to diagnose meningitis?
Lumbar puncture
Where would a lesion be that caused temporal vision loss?
Optic chiasm - bitemporal hemianopia
Where would a lesion be that caused monocular vision loss?
In the eye anatomy or the pre-chiasm nerves
Where would a lesion be that caused field vision loss?
In the brain - likely stroke.
Explain Babinski’s reflex.
Stimulation of sole of the foot should cause scrunched toes, upgoing toes indicates a UMN issue.
What are the 3 spinal tracts and which senses do they carry?
Spinothalamic - pain and temp (early decussation)
Dorsal column - vibration and proprioception
Spino cerebellar - coordination (think cerebellum)
Function of hypothalamus?
Homeostasis
Function of thalamus?
Info integration
What are Glia, and what are some examples?
Glia are non-neuronal nervous tissue.
1. Astrocytes - regulate/upkeep
2. Microglia - phagocytes
3. Oligodendrocytes/schwann cells - myelin
Describe the grey and white matter distribution of the CNS.
Brain has grey on the outside and white on the inside (like a kinder surprise, head is egg shape). Spine is opposite
What are the 4 types of mechanoreceptors and what are each of their depths?
Meissner and Merkel (surface) (MnMs on surface) and Ruffini and Pacinian areas (deep).
Which mechanoreceptors are slow and which are fast?
Angela Merkel likes it rough and slow = Merkel and Ruffini are slow.
Pacinian and Meissner are rapid.
What is the mnemonic for cranial nerve function?
Some Say Marry Money But My Brother Says Big Brains Matter Most
What is the mnemonic for cranial nerve names? (PG13+)
Oh Oh Oh To Touch And Feel A Girl’s Vagina, Ah Heaven.
Olfactory, Optic, Oculomotor, Trochlear, Trigeminial, Abducens, Facial, Auditory, Glossopharyngeal, Vagus, Accessory, Hypoglossal.
What will histology show 12-24 hours after a stroke?
Red Neurons
An issue with which artery can cause bitemporal hemianopia?
Anterior communicating artery
Rupture of an aneurysm in the circle of willis will cause what type of bleed?
Subarachnoid haemorrhage
Which layer of the vessel is broken in a true aneurysm and which in a dissection?
Media in aneurysm, intima in dissection.
Which group of diseases increase the risk of cerebral aneurysms?
Any connective tissue issue such as Polycystic Kidney Disease or Marfans
How would you describe an epidural hematoma?
Red lemon, usually trauma. Often young people.
How would you describe an subdural hematoma?
Blue banana, can be chronic, often older people
What is the pattern of a subarachnoid haemorrhage on a CT?
Bright tracks along the sulci and fissures, often due to aneurysm. Looks like a STAR.
What is the pattern of a intraparenchymal bleed on a CT?
inside brain, often circular.
Which cranial nerve is impacted most by raised ICP?
CN3, oculomotor, down and out eyes direction, blown out pupils.
What type of Hypersensitivity is MS and what is the typical presentation?
Type IV, delayed, young person with optic neuritis.
Where do monosynaptic neuron relationships occur?
Only with stretch receptors and the motor neuron the same muscle
Chronic pain is also called?
Neuropathic pain
Visual hallucinations are typical of what?
Delirium
Which vertebrae correspond to the sympathetic nervous system and which correspond to the parasympathetic?
T and L for symp, S and C for para.
Where are the nuclei and ganglia of the sympathetic nervous system?
Nuclei initially in the intermediolateral nucleus of spinal grey matter, ganglia are in para-vertebral (sympathetic latter) or pre-vertebral
Where are the parasympathetic ganglia?
Brainstem nuclei for C and intermediolateral nucleus for S
Where does the middle meningeal artery come from?
External carotid > Maxillary > Middle Meningeal
Why does a Basilar Artery stroke cause locked-in syndrome?
The basilar artery supplies the pontine arteries, so without blood supply to the pons. Pons is needed to relay info.
Which neurotransmitters are used by the pre-ganglionic and post-ganglionic neurons of the sympathetic and parasympathetic systems?
Symp: pre: Ach(N) and post: NA
Para: pre: Ach(N) and post: Ach(M)
What is the main neurotransmitter for pain?
Glutamate
Which part of the vertebral columns are devoted to sensory areas and which to motor?
Dorsal is always sensory. Dorsal root = sensory. Dorsal horn - sensory.
Ventral is movement.
Which memory types are reduced by age vs by dementia
Episodic memory is reduced by age and procedural memory is reduced by dementia.
What are the causes of delirium?
Mnemonic: DELIRIUM
D - drugs
E - Electrolytes
L - lack of drugs
I - infection
R - reduced senses
I - intracranial pressure
U - urinary retention
M - MI
What type of incontinence do UTI’s cause?
Urge incontinence, vs stress.
What is the anterior attachment of the falx cerebri meningeal layer?
Ethmoid bone crista galli (it’s like a fin)
What bones form the boundaries of the nasal cavity?
Roof - ethmoid bone
Floor = maxillary bone and Palatine
Back = Sphenoid and Palatine
What bones form the boundaries of the oral cavity?
Roof = maxillary bone and palatine
Floor = mandibles
Which cranial nerve innervates the superior portion of the nasal cavity?
CN 1 - Olfactory
Describe the distribution of conchi (turbinates), meatuses and paranasal sinuses.
3x conchi on each side to humidify air, a meatus under each conchi with gaps (foramen) into the sinuses. Frontal sinus, ethmoid sinus, sphenoid sinus, maxillary sinus.
Describe the innervation of the paranasal sinuses?
Frontal, sphenoid and ethmoid are all the ophthalmic branch of the trigeminal (hence eye pain in sinus infection), the maxillary sinus is innervated by the maxillary branch of the trigeminal (hence cheek pain).
Describe the vascularisation of the nasal cavity?
Front: facial artery
Back: sphenopalatine artery
Bottom: palatine artery
Top: ethmoid arteries
ALL EXTERNAL CAROTID
Describe the innervation of the nasal cavity?
Top half = ophthalmic of trigeminal
Bottom half = maxillary of trigeminal
EXCLUDING CN1 AREAS
Describe the motor innervation of the tongue muscles (internal and external)
All are hypoglossal (CN12) apart from the palatoglossus muscle which is vagus (CN10).
Describe the innervation of the teeth?
Top: superior alveolar (maxillary trigeminal)
Bottom: inferior alveolar (mandibular trigeminal)
What are the areas of the larynx and where does the larynx start and end?
Hyoid bone, thyroid cartilage and cricoid cartilage. It starts at the epiglottis and ends at the cricoid cartilage -C6 (trachea).
Describe the distribution and function of the vocal cords.
The arytenoid cartilages sit on top of the cricoid cartilage (below Adam’s apple) and attach to the vocal cords (vocal ligaments). There are false vocal cords (vestibular folds) above to protect the true vocal cords. Moving the arytenoids closing together allows for sound.
Explain why ‘posterior’ parts of the larynx are used for breathing.
The posterior thyroid cartilage is deficient in cartilage to allow air through and the posterior cricoarytenoid muscle pulls the vocal cords apart to allow for air to pass through.
Describe the innervation of the larynx?
It’s all vagus (CN10) - the recurrent laryngeal is interesting because it descends into the thorax before returning to come back up - will cause a hoarse voice if damaged in surgery.
Describe the vascularisation of the larynx?
Done by the laryngeal arteries which come from the thyroid arteries.
What is the function of the salpingopharyngeus muscle?
To open the foramen in the nasal cavity the leads to the eustachian tubule to equalise pressure in the middle ear.
Which nerve(s) control the gag reflex?
Sensory - glossopharyngeal (CN9)
Motor - vagus (CN10)
Mnemonic for the external carotids:
Seven Loud Femmes Arguing Over PMS
S uperior thyroid
L ingual
F acial
A scending pharyngeal
O ccipital
P posterior auricular
M axillary
S uperficial temporal
What are the 3 deep fascial layers of the neck and the 3 ‘V’ compartments of the neck?
Investing fascia, pretracheal, prevertebral.
3 V’s: visceral, vertebral, vascular
The investing fascia splits to encapsulate which muscles?
The SCM and the Traps
Which major vessels lie between the platysma and the investing fascia?
External and Anterior Jugular veins (internal are in carotid sheath)
The investing fascia tightly hugs the vertebral fascia and the vertebrae at what level?
C7
Why are the layers and connection points of the pretracheal fascia clinically relevant?
An infection of the visceral but NOT muscular pretracheal fascia can spread to the pericardium as the visceral compartment connects to the pericardium (starts at hyoid).
What are the connection points for the vertebral fascial compartment of the neck?
Bottom of the skull to the axilla of the arm.
What key features are in the carotid sheaths?
Common/internal carotid, internal jugular vein, vagus nerve, lymph nodes.
What are the hyoid muscles of the pretracheal muscular fascia used for and how many are there?
Used for swallowing and eating, 4x below the hyoid and 4x above. Most have hyoid in the name except diagastric and sternothyroid).
What is the progression of the first branch of the external carotid?
Becomes the superior thyroid artery to supply most of the thyroid and then becomes superior laryngeal for the larynx.
Which nerves are in the anterior triangle?
CN 9-12. Only 12 gives off no branches in the triangle.
What are the borders of the posterior triangle, and what important vessels/nerves run through this area?
SCM, clavicle, Traps
Vessels: part of occipital artery (ext. carotid) on its way to the back of the head, subclavian artery, subscapular arteries and external jugular vein.
Nerve: CN 11 - Accessory. As well as cervical plexus (gives phrenic) and brachial plexus.
Which 2 lymphatic areas are key for detecting extensive disease in the lymphatic system of the head and neck?
The jugulofacial nodes and the jugulosubclavian nodes.
Surgery around the thyroid may commonly damage which nerve?
The recurrent laryngeal - leading to hoarse voice.
What are the 3 divisions of the brainstem and the 3 layers of the brainstem?
Midbrain, Pons, Medulla - split into tectum (roof), tegmentum and basis.
What is located in the brainstem tegmentum and what is located in the brainstem basis?
Tegmentum - Cranial Nerve Cell bodies (3-12)
Basis - all the descending tracts.
Describe the cranial nerve nuclei distribution in the brainstem?
The motor CN nuclei are ventral, ventral is always motor, and the sensory nuclei are lateral, not dorsal because the 4th ventricle pushes them laterally.
What are the general functions of the midbrain, pons and medulla.
Midbrain - alertness and wakefulness.
Pons + Medulla - autonomic/reflex functions.
Which main 3 sensory tracts do I need to know what what do information do they carry?
Dorsal column - vibration, proprioception, fine touch
Spinocerebellar - coordination
Spinothalamic - pain and temperature
All of the tracts cross at the medulla except the ____.
spinothalamic
Which Cranial Nerves are involved in eye movement and which muscles do they control?
CN 3, 4 and 6.
3 - MR SIRIO - Medial, Superior, Inferior Rectus and Inferior Oblique.
4 - superior oblique
6 - LASER - Lateral (Six) Rectus
What is the skull opening for the first cranial nerve?
Cribiform plate of the ethmoid
What is the skull opening for the second cranial nerve?
Optic canal opens through the sphenoid
Which reflex test tests the midbrain and how?
The pupillary light reflex - sensory part is optic nerve and motor part (iris control) is oculomotor.
Which reflex test tests the pons and how?
The corneal reflex test - sensory is the ophthalmic branch of the trigeminal and motor part (orbicularis oculis) is facial nerve, both of which have their cell bodies in the pons.
Which reflex test tests the medulla and how?
The gag reflex - sensory is the glossopharyngeal nerve and motor is the vagus - both of which have their cell bodies in the medulla.
Which cranial nerves exit together in the superior orbital fissure?
3, 4, 6, and 5.1 - ophthalmic.
Which ‘special’ functions does the facial nerve have aside from its motor functions?
Innervation of the stapedius in ear (muffles chewing sound), tears, salivary glands (but not parotid) and taste.
Which nerve does CN7 travel with and where do they exit the skull?
CN8 (auditory) - the internal acoustic meatus
Which CN innervates the parotid?
CN9 - glossopharyngeal
Where does the accessory cranial nerve arise and what does it control?
Actually arises in the spine, not the brainstem, controls the motor part of the SCM and traps.
Name 2 reasons why CN4 is special.
CN4, the trochlear nerve, is special because it is the only cranial nerve to exit the brainstem dorsally and it also is the only cranial nerve to deccusate - so it controls a contralateral area unlike all the others.
Which 4 CN have parasympathetic fibres?
Vagus (10), glossopharyngeal (9), oculomotor (3) and facial (7)
What is the most common adult CNS tumour and what is the prognosis?
Meningioma - good prognosis.
Describe the distribution of adult vs child CNS tumours.
Adults tend to have tumours above the tentorium cerebelli (dural layer serperating cerebrum from cerebellum), whereas children tend to have tumours below that line.
What do Glioblastomas look like on histology and what is their prognosis.
They have palisade necrosis - a wall of purple nuclei around pink necrotic areas.
What do Meningiomas look like on histo?
Big pink swirls.
Schwannoma are mostly related to which CN and therefore how do they often present?
CN 8 - often with tinnitus and hearing issues.
What is the most common childhood CNS tumour?
Pilocytic astrocytoma
Which childhood CNS tumour has the worst prognosis?
Diffuse midline glioma
Which fungi can cause lesions that appear similar to tumours in the CNS.
Cryptococcus - when immunocompromised.
Which medication type is used for bipolar?
Lithium
What bones form the outer borders of the orbit?
Frontal bone is the roof, zygomatic and maxilla form the rest.
Where is the ciliary body located and what are its two functions?
In the middle layer of the eye (along with the iris and choroid) - it makes the aqueous humour for the anterior chamber and it also controls the ‘accomodation’ of the lens via ciliary muscles
What substance creates the intraoccular pressure?
Aqueous humour
What is a degradation of the lens’ ability to accomodate called?
Presbyopia
Describe the location and anatomy of the fovea.
It lies in the centre of the macula and is totally avascular, it only has cones, no rods.
Which carotid branch vascularises the entire eye and list its four branches.
The ophthalmic branch of the internal carotid, it splits into the central retinal artery which does the retina, and then the 2 posterior arteries which pierce the eyeball and the single anterior artery which doesn’t pierce the eyeball and does the conjunctiva.
Which photoreceptors do we use at night?
Rods
What are the 3 major cells in the photoreception cascade?
The photoreceptors, the bipolar cells and the ganglion cells.
Describe phototransduction.
Light activates -opsins (rhodopsin or cone-opsin) which changes its relationship with vitamin A and eventually causes hyperpolarisation.
Describe the information path for visual information from the eyes.
Photoreceptors in retina > bipolar cells > ganglion cells > Lateral Geniculate Nucleus (LOGAN) in the thalamus > to the primary visual cortex in the occipital lobe > on towards the ventral (colour) or dorsal (motion) paths.
Describe vision losses associated with lesions at different areas of the optic pathway.
Pre-chiasm: monocular
Chiasm: bitemporal hemianopia
Post-chiasm: everything else, especially homonymous hemianopia
What is macular sparing and why does it occur?
Field loss with central area spared corresponding to fovea/macula due to different blood supply to fovea as it is most posterior area of occipital lobe.
Describe two types of non-visual information provided by optic ganglia and their paths.
- Intrinsically photosensitive (no photoreceptor required) ganglion cells allow for circadian rhythm and sleep patterns - down at suprachiasmatic nucleus of hypothalamus.
- Pupil response done by intrinsically photosensitive ganglion with pretectal nucleus involvement.
Describe the dorsal and ventral visual paths.
Dorsal: is all motion. M ganglion cells through LOGAN to visual cortex and up dorsally to MT area (middle temporal) for motion control.
Ventral: is all colour. P ganglion cells through LOGAN to visual cortex and down ventrally to IT area (inferior temporal) for colour and in particular, facial recognition at IT.
What are monochromancy, dichromancy and anomalous trichromancy.
Only having 1 cone type, 2 cone types, or having all 3 but distribution is cooked.
Which prefixes are used to describe the three cone types?
Pro - Red (R)
Deut - Green (G)
Tri - Blue (B)
reverse alphabetical
Describe the action of the superior oblique muscle.
Intorsion and down movement, mostly just look down medially.
Describe the action of the inferior oblique muscle.
Extorsion and up movement, mostly just looking up medially.
Describe the 6 muscles involved in the points on the ‘H’ test.
Up and Out: SR
Lateral: LR
Down and Out: IR
Up and In: IO
Medial: MR
Down and In: SO
How can eyes ‘stay still’ during head movement and which cranial nerve is key to this?
The vestibulo-occular reflex, largely controlled by CN8.
Which two ear muscles are involved in dampening down noise and which cranial nerves contol them?
Tensor tympani by the trigeminal and stapedius by the facial (seventh for stapediua)
Where is the organ of corti?
cochlea
Which area of the brainstem helps to localise sound eg. comparing right to left
olives of the pons
The motor movement pathway of the corticospinal tract consist of how many neurons and what do we call them?
2, UMN and LMN
Describe the 3 neuron path of the dorsal column and the anterolateral system
Dorsal column:
1. Sensor all the way up to medulla
2. Medulla top thalamus (medial lemniscus tract) (deccusate)
3. thalamus to cortex
Spinothalamic:
1. Sensor with immediate synapse in grey matter of dorsal horn (decussate)
2. Grey matter to thalamus
3. thalamus to cortex
Describe the location of the dorsal column, spinothalamic tract and corticospinal tract in the white matter of the spine.
Dorsal column = dorsal duh
Lateral corticospinal tract = lateral
Spinothalamic tarct = also called anterolateral system = front and lateral
Why does the retina have a blind spot?
The ganglion pass through as an ‘optic disc’ so there are no photoreceptors there
Explain the difference between a T1 and T2 MRI.
T1 tells the truth - so myelinated tissue is white as it should be.
T2 is opposite.
Fasiculations are associated with what type of motor neuron lesion?
LMN
Vestibular Schwannoma is likely to impact which Cranial Nerves? How will it present?
CN7 and 8, likely dizziness and hearing issues.
Symptoms of Horner’s syndrome?
S - Sympathetic
P - Ptosis
A - Anhydrosis
M - Miosis
What does the Insula cortex do?
perceives body changes and recognises emotions, particularly disgust.
What is functional neurological disease?
psychiatric factors leading to disease, may or may not accompany biological disease. Emotional states converts into real symptoms.
What are the 3 main causes of bacterial meningitis and what are their gram stains?
H. influenzae - gram neg, pleiomorphic
S. pneumoniae - gram pos, diplococci
N. meningitidis - gram neg - diplococci
How to treat bacterial meningitis?
Ceftriaxone to cover the top 3 causes and then add a penicillin for Listeria.
Causes of bacterial meningitis in neonates?
E. coli, Group B strep (S. agalactiae), Listeria.
What is the meningism triad?
Fever, headache, photophobia/neck pain.
Main cause of viral meningitis?
Enteroviruses (or HSV-2)
Which type of meningitis often comes with rash?
N. meningitidis infection
How does TB meningitis present on CSF lumbar puncture?
Mix of bacterial and viral presentation.
Viral characteristics: clear CSF, lymphocytic.
Bacterial characteristics: protein high, glucose low, pressure high.
Why do a CT before a lumbar puncture?
To check for raised ICP, as removal of CSF from spine could create pressure gradient that causes coning of brainstem through foramen magnum.
Main cause of encephalitis?
HSV-1.
Mild brain trauma is another word for ___?
concussion
Describe the physiology of an extradural hematoma.
Red Lemon. Bleed due to trauma (question will be about a young person) of the pterion leading to torn middle meningeal artery filling extradural space.
Describe the physiology of a subdural hematoma.
Blue banana. Venous, particularly bridging veins to saggital sinus.
Give a step by step rundown of raised ICP.
Initial response to brain lesion is to excrete as much CSF and venous blood as possible.
ICP rises after limit is reached.
Herniation.
Once above arterial pressure, get global ischaemia.
Edema can obstruct CSF channels leading to hydrocephaly.
Main brain herniation sites:
- Tenterium cerebelli - impacts CN3.
- Falx cerebri
- Foramen magnum
Vertebral disc prolapse is most likely to affect which area of the spine, causing what type of deficits?
Discs tend to herniate postero-laterally which can impact the anterior segment of the spinal column, corresponding to the ventro-medial part of the spine. This will cause motor deficits.
Describe the Anterior cerebral artery and which brain areas it feeds.
Comes off the circle of Willis anteriorly and feeds the medial areas of the brain, including parts of the frontal and parietal lobes.
What presentation will an ACA stroke likely cause?
Contralateral lower limb hemiparasthesia and hemianasthesia.
Describe the Middle cerebral artery and which brain areas it feeds.
MCAs come straight off internal carotids and feed the lateral cerebrum including areas of all of the lobes. It includes Broca’s and Wernicke’s areas.
What is medial-medullary syndrome and what causes it?
Stroke due to issue with the anterior spinal artery, famously causes tongue motor losses.
Describe the structure of a ‘motor-unit.’ Which motor units are activated first.
A single LMN supplies many muscle fibres but each fibre is innervated by only one motor neuron. The smallest motor units are always activated first.
Describe the distribution of motor areas in the spinal cord and what particularly arms of motor function do they control?
Can split the motor function of the spine into the corticospinal tract (lateral) and the ventro-medial area. The corticospinal areas which control more distal areas like the limbs. The more medial area, the ventromedial area, controls more central motor functions such as posture and balance.
What is the difference between decerebrate and decorticate presentations?
Decerebrate: more E’s so think extensive and done by ventromedial area (corticospinal has no E’s). Both arms and legs are extended.
Decorticate: Legs are extended but arms are flexed.
What is a ‘Feed Forward’ mechanism?
Anticipation of postural disturbance and subsequent movement. eg. incoming ball we need to catch.
Weird gaits tend to be caused by which type of lesion?
Circumducting and hemiparetic gait issues are caused by UMN issues impacting adductors.
What is the function of the basal ganglia?
Transmission of motor info between cortex and thalamus, movement patterns (eg. playing an instrument) and initiating movement.
What area of the brain is associated with Parkinson’s and what are the Parkinson’s triad?
The substantia nigra.
1. Tremor
2. Rigidity
3. Bradykinesia
What is special about Cerebellar lesions?
They affect the ipsilateral side of the body.
What are the functions of the cerebellum?
Coordination, planning movement - ataxia results from cerebellum issue = movements slightly off.
What are the main functions of each of the brain lobes?
Frontal: motor, planning, ‘why’
Parietal: somatosensory, visual
Temporal: Memory, auditory, emotion, language
Occipital: Visual
Describe Broca’s aphasia?
Non-fluent, grammatically incorrect speech with retained comprehension that accurately answers the questions asked.
Describe Wernicke’s aphasia?
Fluent, word-salad, loss of comprehension, non-sensical. Paraphasia present.
What histological presentation is present 24hrs after an ischaemic stroke?
RED NEURONS - pinker/redder nuclei than normal, cells sort of comma shaped
Which region of the brain is good to check for global ischaemia?
CA1 region of Hippocampus - spans multiple lobes.
Most common sites of atheroemboli for strokes?
Carotid bifurcation, MCA bifurcation, aortic bifurcation.
Reperfusion injuries can cause what issue?
Haemorrhagic infarct.
List 3 reasons why strokes kill?
Pneumonia (aspiration), vital brain centre death, brain swelling, CVD, PE.
What are the main two causes of Haemorrhagic stroke?
HTN small vessel disease (hyaline ateriosclerosis of basal ganglia and diencephalon) and amyloid angiopathy (like Alzheimers).
How does amyloid angiopathy present on histology?
Thick pink vessel walls
What is the most common non-traumatic cause of a subarachnoid haemorrhage and what are its risk factors?
Berry (Saccular) aneurysm.
Risks: age, connective tissue disease (PCKD), HTN, Smoking.
Where do berry aneurysms tend to occur?
They prefer anterior segments of the brain.
Occur at MCA bifurcation, Anterior communicating bifurcation, int. carotid with posterior communicating bifurcation.
How can aneurysms cause hydrocephaly?
Haemorrhage causes blood clot which can cause ischaemia to areas and can obstruct path of CSF leading to hydrocephaly.
Symptoms of Parkinson’s outside of the typical triad?
Loss of smell, depression, anxiety, sexual dysfunction, bowel and bladder issues.
What is the main pharmacological intervention for Parkinson’s?
Levodopa - mixed L-Dopa and peripheral dopamine receptor inhibitors to reduce side effects. (L-Dopa mixed with carbidopa or benserazide).
Side effects of Levidopa?
All the pro-dopamine stuff like anorexia, nausea, vomiting, tachycardia, arrythiamas, hallucinations, mood changes, anxiety, depression.
Which protein is key for development of Parkinson’s?
alpha-synuclein.
Ig to which strain of which meningitis bacteria cannot be treated for in an agglutination.
Group B N. meningitidis - polysaccharide capsule too similar to self antigens.
Which 3 bacteria should be considered in neonatal meningitis?
Group B strep (S. agalactiae), E.coli and Listeria
Which type of viruses cause Viral meningitis and which cause viral encephalitis?
Enteroviruses for meningitis and HSV-1 for encephalitis
What are unstable repeat expansions?
Expanded DNA segments of a gene due to dynamic mutations, typically in trinucelotides, that can cause disease.
What is genetic anticipation?
Build up of expansion repeats over generations leading to earlier or more intense disease
What are the impacts of mutations in non-coding vs coding regions?
Non-coding - typically makes loss of function protein or RNA
Coding - typically makes gain of function pathological proteins
Describe the genetics of Huntington’s disease?
A neurodegenerative disease due to triplet expansion leading to poor motor skills and psychiatric issues, movement worse than Parkinsons. Chromosome 4 is the site of HTT gene for protein huntingtin.
Name 2 ethical issues for pre-symptomatic genetic testing.
- family might not want to know
- life/disability insurance
Mnemonic for pre-frontal cortex.
ELMMLO
E - executive
L - lateral (dorso)
M - motivation
M - medial
L - Limbic
O - orbital
Name one key factor that could limit recovery in someone with a pre-frontal cortex issue?
Insight.
What are the types of memory?
Short Term (working) and Long term. Long term is split into explicit (episodic and semantic) and implicit (procedural).
Name 1 cause of acute, insidious and paroxysmal memory loss.
Acute - surgery, bleed, hypoxia, thalamic infarct (ischaemia).
Insidious - Alzheimers (primary), alcoholism (secondary).
Paroxysmal - ptsd, epilepsy.
What is the prodrome from Alzheimers?
Mild Cognitive Impairment
What are the differences in regeneration ability for the CNS and PNS and which cells are involved?
PNS is much better at regeneration than the CNS.
Oligodendrocytes in the CNS are inhibitory to regeneration whereas PNS Schwann cells are stimulatory.
What is scarring of neural tissue called and why does it happen?
Gliosis/glial scarring due to too much astrogliosis (proliferation of astrocytes after damage).
Steps in PNS regeneration:
- Loss of Nissl bodies (RER).
- Schwann cell proliferation to form new cord
- Regeneration or failure (neuroma)
Compare regeneration in a cut verses crushed axon
Crushed is much better for healing as the ECM often remains intact and acts as a scaffold for regrowth, some of the axon may also survive.
Name two drug targets that could improve neural regeneration
- astrocytes - too many impedes regrowth
- T cells - hang around in neurons after damage for life and impede healing
Steps to assessing capacity:
- can they understand your info
- can they retain it
- can they use the info/weight it
- can they communicate their decision
COGNITIVE IMPAIRMENT DOES NOT AUTOMATICALLY EQUAL NO CAPACITY
What are the two forms of Alzheimers and the pathology behind both?
Early onset (inherited) - mutation results in increased protein production - around age 45
Late onset (sporadic) - poor protein clearance - around age 78
Risk factors for Alzheimers
- genetics
- Trisomy 21
- age
Which two protein features accumulate in Alzheimers and where do they appear?
Beta-amyloid plaques and neurofibrillary (tau) tangles that form in the temporal lobe.
What protein forms the amyloid plaques and which allele is a risk factor for their formation?
APP protein form beta amyloid plaques and E4 is the risky allele.
Potential treatment for Alzheimers?
MAB to Beta amyloid protein - passive immunisation. eg. Aducanamab
What is CJD and how does it present on histopathology?
Creutzfeldt-Jakob Disease, a prion, which causes spongiform encephalopathy (looks like a sponge on Histo).
How does CJD spread and what is the incubation time?
Spreads via eating infected tissue but the variant form can spread through blood. Incubation time is 6-15 years.
What is the cardinal feature of Parkinson’s on histo?
Lewy Body protein buildup (a-synueclin).
What is the first thing to do when a patient has a stroke?
CT
What are the stages of stroke on Histopathology?
- Within 24 hrs - Red Neurons
- After a day - neutrophil (polymorphonuclear) infiltrate
- Mononuclears (monocytes + lymphocytes) start removing debris - some clear areas.
4 - Foamy Macrophages
5 - gliosis
What is the triad of meningism?
Headache, neck stiffness, photophobia.
NOT FEVER (fever would be present in meningitis though).
What test is used to measure consciousness?
Glasgow coma score
What is the main cause of SAH and what are some other non-traumatic causes?
Main: Berry Aneurysm
Others: Coagulopathies, HTN, vasculitis etc.
Name two tests to diagnose MS.
- MRI
- IgG for oligoclonal bands
Where do MS plaques tend to cluster?
Paraventricular dymyelinated plaques .
Describe MS histo.
Purple Wall around lots of pink cells (blood), not dissimilar to palisading necrosis.
What is the most common form of MS in terms of timeframe?
Relapsing-remitting.
Should you do a lumbar puncture for suspected meningitis?
NO - you must check for raised ICP first with a CT to ensure you don’t cause coning.
Ways to check for raised ICP?
- CT
- Papilloedema on fundoscopy
How can you tell if an image is a CT?
Bone will be white.
Describe the histology and grading of GBM.
(pseudo)Palisading necrosis and is always grade 4.
Which genetic/protein markers are important for development of GBM?
- Chromosome 1 and 19 FISH test to predict GBM development (1p19q)
- and if IDH1 protein is present it is protective
Would a left hemisphere lesion cause right hemineglect?
No - as the right side of the body is controlled by both hemispheres. The left side of the body however is only controlled by the right hemisphere, so a lesion there would cause hemineglect.
What is ataxia?
Poor coordination
Describe the anatomical progression of the neurons in the coronal radiata
Coronal radiata –> internal capsule –> cerebral peduncle –> pyramids
Describe the anatomy of the internal capsule and a mnemonic to help you lable the inferior view.
Next door (inferior and lateral) to the lateral ventricles. Start at the Thalamus the big grape looking things under the ventricles. Move up into the globus pallidum, then up again through the internal capsule to the putamen. Above that is the caudate nucleus.
The corticobulbar tract for. theface is closest to the caudate nucleus, corticospinal tract for the body is more posterior.
The Goat Produces Cheese
Thalamus Globus Putamen Caudate
How can you orient yourself in a coronal section of the internal capsule?
If the caudate nucleus can be seen, it’s anterior.
What would an internal capsule lesion impact?
Motor control of limbs due to corticospinal tract as well as movement of the face as the corticobulbar cranial nerves (5, 7, 9, 10, 11, 12)
Where is the substantia nigra located?
It is in the midbrain
What 5 nuclei form the basal ganglia?
Putamen, globus pallidus, caudate nucleus, subthalamic nucleus, substantia nigra.
What two areas form the corpus striatum?
Putamen and Caudate.
Describe the direct and indirect pathways of the basal ganglia and the functions of the involved neurotransmitters.
Direct: just GABA - excites movement.
Indirect: uses substantia nigra and dopamine. for inhibition.
Why does Parkinson’s affect movement?
Dopamine controls movement based signals in the thalamus, loss of this dopamine causes inhibition of the thalamus and the weakening of motor control.
What is diplopia?
Double vision
What word is used to describe herniation of the tentorium cerebelli? What about the foramen magnum?
Tenotrium = uncal
Foramen magnum = tonsillar
Compare the staggered movements of the tongue and uvula in damaged cranial nerves.
Tongue never lies - points towards issue.
Uvula is opposite - points away from issue.
Name one key clear difference between delirium and dementia.
Delirium often has absent focus - inattentiveness
RAPD must be due to an issue where?
Retina or optic nerve
Which neck compartment is the thyroid in?
Pretrachaeal
What sense travels in the medial geniculate nucleus?
Hearing
What subunits make up APP protein?
BY secretase (Beta and gamma)
What is conduction aphasia?
Different to the other aphasia types as it is notably an inability to repeat back phrases
Name the foramen for each of the cranial nerves.
- Cribiform plate
- optic canal
3, 4, 6 and 5.1. Superior orbital fissure
5.2. Foramen rotundum
5.3. Foramen ovale
7 and 8. Internal acoustic meatus
9, 10 and 11. Jugular foramen - Hypoglossal canal
How would you differentiate a MCA stroke from a leticulostriate stroke?
MCA should impact both sensory and motor.
The leticulosteriate arteries supply the basal ganglia so just present with motor deficits.
Describe the abundance of Ach during Parkinson’s
Increased (in relation to dopamine)
Which WBC would be found in CSF of an MS patient?
Lymphocytes (think oligoclonal IgG being made
Which cause of meningitis is most common in neonates, young kids, young adults and the elderly?
Neonates - Group B strep
1-2 y/o - strep pneumonaie
young adults - N. meningitidis
Olds - E.coli and Listeria
Optic neuritis can cause which finding on examination?
RAPD
Which artery supplies the optic disc?
Short posterior ciliary
