Neuro Flashcards
CN 9 does
CN 10 does
Carotid BP
Aortic BP
Clinical significance of ACA rupture
Subarachnoid haemorrhage
Sits on top of the optic chiasm
Vision problems
Most common place for berry aneurysms
Anterior communicating aneurysm –> visual defects
Most common place for non traumatic intraparenchymal haemorrhage
Lenticulostriate arteries off the MCA
Anterior spinal artery supplies
Pyramids of medulla
Medial lemniscus of medulla
Nucleus of 12 nerve
Anterior 2/3rds of spinal cord
Derivatives of neural crest cells
PNS (peripheral nerve cells, spinal ganglia/autonomic ganglia)
Adrenal medulla
Skin melanocytes
Anomalies in the development of the spinal cord
Spina bifida occulta
Meningocele
Myelomeningocele
Rachischisis
The most common site where the neural folds fail to neurulate
Cranial neuropore
Resulting in craniorachischisis or anencephaly
What are the parts of the corpus callousum
Rostrum
Genum
Body
Splenium
Three parts of the inferior frontal lobe
Orbital
Triangular
Opercular
Where is Broca’s area found
Inferior frontal gyrus
On the contralateral hemisphere of dominant hand (usually left)
The three types of cortex
Archicortex- limbic system
Paleocortex- olfactory bulbs
Neocortex (90%) - cerebral hemispheres
White matter is composed of what types of fibers
Association fibers - connect cortical areas in same hemisphere
Projection fibers - connect cortex to subcortical areas (internal capsule)
Callosal fibers (connect cortical areas between hemispheres (corpus callousum, anterior and posterior commisures)
Major components of diencephalon
Thalamus (important nuclei include lateral and medial geniculate nuclei for vision and hearing respectively)
Sub thalamus (motor function)
Epithalamus (includes pineal gland, dorsomedial to thalamus)
Hypothalamus (main visceral control system)
What does the hypothalamus control
ANS and emotional response together with limbic system
Body temp
Food intake
Water balance
Sleep/awake cycles
Hormones
Control pituitary gland hormone prod (eg growth and cortisol etc)
What does the pineal gland do?
Produces anti-gonadotropic hormone and melatonin
Critical for sleep, helps you dream
Removal of gland –> early puberty
Overstimulation –> delayed puberty
What are the parts of the diencephalon?
Thalamus Intrathalamic adhesion Pineal gland Hypothalamus (in the space between third ventricles?) Third ventricles Mammillary body Posterior lobe of pituitary Supraoptic recess Infundibular recess Infundibulum
Which layer of meninges forms the blood brain barrier?
Arachnoid
And forms the subarachnoid space with CSF and major arteries
Which part of the nervous system do the cranial nerves belong to?
All belong to PeripheralNS except CNII (tract of diencephalon)
CN I
Olfactory epithelium on superior concha to
Cribiform plate of ethmoid bone to
Olfactory bulb to
Olfactory tract (special sensory and efferent fibers)
Problem–>
Anosmia
Uncinate fits (olfactory hallucinations)
CN II
Retina Through optic canals (optic nerve) Optic chiasm (Optic tract ) (Passes pituitary) Lateral geniculate bodies
Complications:
Optic neuritis
Visual field defects
Bitemporal hemianopsia
(Right) monocular blindness
(Left) homonymous hemianopsia
CN III
Motor, parasympathetic
(Sympathetic comes from internal carotid plexus)
Motor: Occulomotor nucleus Cavernous sinus Superior orbital fissure Muscles (superior medial and inferior rectus, inferior oblique, levator palpebrae superioris "eyelid")
Parasympathetic : Accessory occulomotor nucleus Cavernous sinus Superior orbital fissure Ciliary ganglion Short ciliary nerves --> ciliary muscle and sphincter pupillae
Sympathetic*:
Cavernous sinus and superior orbital fissure
(–> branches off as nasociliary nerve –> long ciliary –> dilator pupillae)
(–> to ciliary ganglion –> joins long ciliary nerve
Occulomotor nerve palsy
And causes
Ptosis No pupillary reflex Dilation of the pupil Eye abducted No lens accomodation
Causes:
Aneurysm of posterior cerebral
Or superior cerebellar artery
CN IV
Motor Trochlear nucleus Cavernous sinus Superior orbital fissure --> superior oblique
Injury :
Diplopia
Trigeminal nerve branches
Ophthalmic nerve --> Lacrimal Supratrochlear Supra-orbital Infratrochlear External nasal
Maxillary nerve –>
Zygomaticofacial
Infra-orbital nerve ( through infraorbital foramen)
Zygomaticotemporal
Mandibular –>
Mental nerve through mental foramen
Buccal
Auriculotemporal
Course of trigeminal nerve
Superior orbital fissure - ophthalmic (foreheads)
Foramen rotundum - V2 (teeth, face)
Foramen Ovale –> mandibular nerve (teeth, chin, muscles of mastication)
CN V1
Trigeminal ganglion
Superior orbital fissure (meningeal branch to tentorium cerebelli comes off before this)
–> frontal nerve , nasociliary nerve , lacrimal nerve
Frontal –> one branch to frontal notch (–> supratrochlear) and one to supraorbital foramen (–> supraorbital nerve)
Nasociliary –> long ciliary nerve passes through ciliary ganglion , ethmoidal nerves through anterior/posterior ethmoidal foramen (to ethmoidal and sphenoid foramen)
Nasociliary turns into infratrochlear supplying nasal cavity and side of nose
Sympathetic innervation from carotid plexus –> short ciliary nerves to ciliary muscles via ciliary ganglion
Trigeminal neuralgia
Toothache Headache earache Sinusitis Severe neuralgia of unknown causes
Pain can be precipitated by speaking , eating , light touch, draughts on face
Patients can become suicidal because of severe pain
Pain paroxysms in certain sensitive spots for each division
1st - supraoptic notch
2nd - junction of nose and face
3rd - mental foramen
Injury to a given division of trigeminal nerve causes
Sensory loss over area supplied
Injury to mandibular nerve
Paralysis of muscles of mastication and lower jaw deviates to affected side when mouth is open due to unopposed action of opposite pterygoid muscles
Sensory Reflexes supplied by trigeminal nerve
Corneal reflex (closing eyelid on touching cornea) Lacrimal reflex (tears washing eye on irritation) Chewing reflex (by presence of food in mouth) Sneezing reflex (irritation of nasal mucosa)
Referred pain associated with trigeminal nerve
Diseased tooth or cancer of tongue may cause earache or pain radiating up side of head - pain from inferior alveolar nerve or lingual nerve to aurico-temporal
Sever cold on palate - pain over forehead (referred from palatine branches of maxillary division to ophthalmic division)
CN VI
Abducent nucleus
Cavernous sinus
SOF
Lateral rectus muscle
Abducent nerve injury
Long intracranial course Stretched due to fluid pressure Paralysis Diplopia- opposite side of lesion Aneurysm of Willis Septic thrombosis of cavernous sinus
Bell’s palsy
Paralysis of facial nerve for no obvious reason
May occur due to exposure to cold or inflammation that occurs near the stylomastoid foramen which compresses the foramen
Inner ear infection
Otitis media
Slight droop in neutral position
Asymmetry on smile
Inability to close eye tightly
Three main types of brain herniation
Subfalcine
Transtentorial
Tonsillar
Clinical significance of subfalcine herniation
Can compress ACA
Clinical significance of transtentorial herniation
CN III compressed –> pupillary dilation and impaired ocular movements on side of lesion
PCA may be compressed –> infarction and further swelling and thus further herniation and Ischemic injury to primary visual cortex
Bigger herniation – can put pressure on midbrain and compress the contralateral cerebellar peduncle against tentorium resulting in ipsilateral hemiparesis (compression creates Kernohan’s notch)
Progression of hernia often accompanied by linear or flame shaped haemorrhages in midbrain and pons termed Duret haemorrhages