Neuroanatomy Flashcards
rostral
towards the front (rostrum = beak)
caudal
towards the tail
what is the encephalon?
brain
what does the CNS comprise?
brain and spinal cord
what is the rhombencephalon?
hindbrain
what is the rhombencephalon (hindbrain) divided into?
medulla oblongata
pons
cerebellum
what is medulla oblongata derived from?
myelencephalon
what is the pons derived from?
metencephalon
what is the cerebellum derived from?
metencephalon
what is the mesencephalon?
midbrain
in which part of the brain is the tectum?
midbrain
where is the tectum relative to the cerebral aqueduct in the midbrain?
dorsal
which part of the midbrain comprises of four colliculi?
tectum
what is the corpora quadrigemina?
superior and inferior colliculi
what is the cerebral peduncle?
midbrain ventral to the aqueduct
divisions of the cerebral peduncle
dorsal tegmentum
ventrally, a large fibre tract on each side of the midline - crus cerebri
what separates the tegmentum and crura?
substantia nigra
what are the crus cerebri?
large bundles of white matter emerging from the cerebral hemispheres, one on each side of the midline
pass backwards and downwards, converging to meet in the midline at the upper border of the pons
which part of the cerebral peduncles are visible on the inferior surface of the brain?
crus cerebri
what is the prosencephalon?
forebrain
divisions of the prosencephalon/ forebrain
diencephalon and telencephalon
divisions of the diencephalon
thalamus and hypothalamus
with the epi and sub-thalamus
what does the telencephalon consist of?
cerebral cortex (grey matter)
deep nuclei - basal ganglia
where are the red nuclei located?
ventral midbrain
what are the meninges?
three separate tubular sheaths of membrane which surround and enclose the ENTIRE CNS
name the meninges deep to superficial
PAD out
pia, arachnoid, dura
describe dura mater
fibrous sheet
white collagen fibres
few elastic fibres arranged in dense laminae, often of parallel fibres
latticed appearance due to wide angle between the direction of the fibres in adjacent laminae
does the spinal cord dura have an endosteal layer?
no, just cranial dura
layers of cranial dura
outer endosteal layer - equivalent to the periosteum
inner meningeal layer - dura mater proper
describe arachnoid mater
poorly vascularised membrane of loose connective tissue, consisting of collagen, elastin and reticulin fibres
loosely covers the brain without following the gyral and sulcal undulations
describe pia mater
adherent to the entire surface of the CNS, including following the gyral and sulcal folds
what is the subarachnoid space?
space between the arachnoid and pia mater containing cerebrospinal fluid
where is CSF?
in the ventricles and subarachnoid space
what is white matter?
formed by collections of nerve fibres (axons) wrapped in fatty myelin sheaths with few or no neuronal somata (cell bodies)
what is grey matter of the CNS?
formed by aggregations of neuronal cell bodies and their local processes
what is neuropil?
network of intermingled and interconnected neuronal processes which occupy the space between neuronal cell bodies in the grey matter
what are clusters of nerve cell bodies (grey matter) within the brain?
nuclei/ ganglia
e.g basal ganglia
what is the difference between ganglia and nuclei?
why is ‘basal ganglia’ a misnomer?
ganglia are clusters of nerve cell bodies in the PNS
nuclei are clusters of nerve cell bodies in the CNS
basal ganglia are in the forebrain (CNS)
what is the cortex?
outer surface of the brain
cerebral hemispheres AND cerebellum
formed by flatter sheets of neurones
what shape does the grey matter form in the spinal cord?
butterfly
difference in orientation of grey and white matter in the spinal cord and brain
brain
- grey matter surrounds white matter
spinal cord
- white matter surrounds grey matter
- grey matter forms a butterfly shape
which layer of the meninges is indistinguishable with the naked eye?
pia
arterial supply to the brain
Circle of Willis
venous drainage of the brain
cerebral veins
dural venous sinuses
in which lobe is the primary motor cortex?
frontal
in which lobe is the prefrontal cortex?
frontal
in which lobe are the primary auditory cortex and auditory association cortex?
temporal
in which lobe is Wernicke’s area?
temporal
in which lobe is the hippocampus?
temporal
in which lobe is the amygdala?
temporal
in which lobe is the primary somatosensory cortex?
parietal
in which lobe is the somatosensory association cortex?
parietal
in which lobe is the primary visual cortex?
occipital
in which lobe is the visual association cortex
occipital
function of the cerebellum
motor control of equilibrium
posture and muscle tone and movement co-ordination
where are cranial nerve nuclei?
brainstem mainly
what are gyri?
rolls of cerebral cortex
what are sulci?
grooves between the gyri
what is the central sulcus?
large fissure separating the frontal from parietal lobes
what is the lateral sulcus?
large fissure separating the temporal lobe from parietal and frontal lobes
what are the posterior most parts of the occipital lobes called?
occipital poles
what is insula?
forms the floor of the lateral sulcus
what are opercula?
means ‘lips’
the parts of the temporal, frontal and parietal lobes that overlie the insula
where is the median longitudinal fissure?
between the hemispheres
white matter connecting the hemispheres
corpus callosum
ion which lobe do the olfactory tracts run?
frontal
rounded eminences behind the optic chiasma
mamillary bodies
are the mamillary bodies visible from the dorsal or ventral surface of the brainstem?
ventral
what is the only part of the diencephalon visible on the outside of the brain?
hypothalamus
what are the crus cerebri?
part of the cerebral peduncles
two large masses of white matter emerging behind the mamillary bodies on each side, from the cerebral hemisphere
they converge as they meet the pons
bridge of neural tissue between the midbrain and the medulla oblongata
pons
what joins the hemispheres of the cerebellum?
vermis
where does the parietal lobe extend between?
central sulcus anteriorly to the imaginary parietooccipital fissure posteriorly
which lobe contains the primary sensory area?
parietal
how many of each lobe do we have?
2
which parietal lobe is usually dominant?
left
functional of the non dominant parietal lobe
visuospatial functions
function of the frontal lobe
motor function, problem solving, spontaneity, memory, language, judgement, personality, impulse control, social and sexual behaviour
where is the prefrontal cortex?
anterior part of frontal lobe
function of the prefrontal cortex
higher cognitive functions and determination of personality
where is Broca’s area?
left inferior frontal gyrus
function of Broca’s area?
language production and comprehension
where is the primary auditory complex?
temporal lobe
where is the hippocampus?
temporal lobe
in which lobe is the amygdala?
temporal
where is Wernicke’s area?
superior temporal gyrus of the left hemisphere
function of Wernicke’s area
understanding the spoken word
where is the auditory complex found?
lateral/ Sylvian fissure
where are the primary visual and visual association cortices?
occipital lobe
function of the limbic system
emotion, memory, behaviour, olfaction
function of the hippocampus
long term memory formation
function of the amygdala
motivationally significant stimuli e.g those related to reward and fear
what is the brain’s pleasure centre?
nucleus accumbens
falx cerebri
arched crescent of dura lying in the longitudinal fissure between the cerebral hemispheres
sinus at the superior border of the falx cerebri
superior saggital sinus
sinus at the free border of the falx cerebri (inferior margin)
inferior saggital sinus
thick, fibrous roof over the posterior cranial fossa and cerebellum
tentorium cerebelli
sinus within the tentorium cerebelli at its attachment to the falx cerebri (midline of the tentorium cerebelli)
straight sinus
horseshoe shaped space between the free concave border of the tentorium and the dorsum sellae of the sphenoid
tectorial inscisure
sinuses running along the line of attachment of the tentorium cerebelli to the occipital bone
transverse sinuses
sinus lying lateral to the body of the sphenoid
cavernous sinus
small, circular, horizontal fold of dura mater which forms the roof of the pituitary fossa
diaphragma sellae
dura separating the lobes of the cerebellum
falx cerebelli
compartments within the subarachnoid space where the pia mater and arachnoid membrane are not in close approximation and cerebrospinal fluid (CSF) forms pools
subarachnoid cisterns
names after their positions relative to the brain
midline communication between the 4th ventricle and subarachnoid space
foramen of magendie
lateral communication between the 4th ventricle and the subarachnoid space
foramen of luschka
which part of the meninges forms part of the blood brain barrier?
pia mater
function of the blood brain barrier
limits the ability of molecules to pass between the blood and CNS for protection
4 features of the blood brain barrier
- the edges of adjacent endothelial cells that line blood vessels are bonded closely together by tight junctions to prevent molecules passing between them
- the basement membrane of CNS blood vessels lack fenestrations
- contractile pericytes embedded in the basement membrane wrap around endothelial cells, regulating capillary blood flow, immunity and vascular permeability
- astrocyte end feet envelop CNS capillaries and restrict the flow of molecules into the CNS parenchyma
meningism
triad of headache, neck stiffness and photophobia
nausea, vomiting and fever
meningitis
inflammation of the meninges, typically caused by infection
which form of meningitis is serious?
bacterial
extradural haemorrhage
between the skull and dura mater
subdural haemorrhage
between the dura and arachnoid
which type of haemorrhage appears as a crescent on a CT scan?
subdural
subarachnoid haemorrhage
blood between the arachnoid and pia mater
which type of haemorrhage causes a sudden, severe headache?
subarachnoid
bleeding within the brain tissue
intracerebral
amaurosis fugax
temporary loss of vision to one eye
part of a carotid plaque breaks off and occludes the central retinal artery
warning of thrombus of the internal carotid artery - potential for an impending stroke
where do arteries and veins on the surface of the brain lie?
within the subarachnoid space
which arteries supply blood to the brain?
internal carotid and vertebral arteries
what percentage of blood do the vertebral arteries supply to the brain?
20%
what percentage of blood do the internal carotid arteries supply to the brain?
80%
which artery supplies the posterior cerebrum and posterior cranial fossa?
vertebral
which artery supplies the anterior and middle cerebrum and diencephalon?
internal carotid
what pathology commonly affects the cerebral arteries?
berry aneurysms
draw and label the circle of Willis
.
where does the internal carotid arise?
bifurcation of the common carotid at the level of the upper border of the thyroid cartilage
which bone does the internal carotid enter?
temporal
where does the internal carotid divide into its terminal branches?
anterior perforated substance at the medial end of the lateral sulcus
what are the terminal branches of the internal carotid artery?
anterior and middle cerebral arteries
which artery supplies the corpus callosum and medial aspects of the hemispheres?
anterior cerebral artery
which is the largest terminal branch of the internal carotid?
middle cerebral artery
which artery supplies the lateral surface of the hemisphere and the deep structures of the anterior part of the cerebral hemisphere?
middle cerebral artery
what connects the two anterior cerebral arteries?
anterior communicating artery
what connects the internal carotid and vertebro-basilar systems?
posterior communicating artery
which artery supplies the occipital lobe?
posterior cerebral artery
which foramen does the opthalmic artery pass through?
optic canal
which foramen do the ethmoidal artery and vein pass through?
ethmoidal foramen
which foramen does the superior ophthalmic vein pass through?
superior orbital fissure
which foramen does the middle meningeal artery pass through?
foramen spinosum
which foramen does the internal jugular vein pass through?
jugular foramen
which foramen do the vertebral arteries pass through?
foramen magnum
which foramen does the labyrinthine artery pass through?
internal acoustic meatus
is there a functional anastomosis between the anterior and posterior circulations?
no
where do the vertebral arteries arise from?
subclavian artery
where do the vertebral arteries unite, and what do they form?
lower border of the pons
basilar artery
where does the basilar artery lie?
anterior median fissure on the pons
which vessels form the posterior circulation?
vertebral and basilar arteries and branches
posterior cerebral artery
what connects the anterior and posterior circulations?
circle of willis
where are berry aneurysms most likely to form?
anterior communicating artery which lies in the subarachnoid space
types of stroke
ischaemic or haemorrhagic
lasts over 24h (under = TIA)
blood supply to the brain is interrupted
where do cerebral veins drain into?
dural venous sinuses
what are internal cerebral veins?
run within the substance of the brain tissue and end when they reach the surface of the brain where they become external cerebral veins
what are external cerebral veins?
run on the surface of the brain, crossing the subarachnoid space to drain into the dural venous sinuses
which vein drains the deep structures of the brain?
great cerebral vein of Galen
where does the great cerebral vein (of Galen) drain into?
straight sinus
draw and label the dural venous sinuses
.
where do ALL the dural venous sinuses drain into?
internal jugular veins
a deep groove in the mastoid portion of the temporal bone
sigmoid sinus
sinus beside the body of the sphenoid bone
cavernous sinus
what does the cavernous sinus contain?
five cranial nerves and the internal carotid artery
carotid plexus
cranial nerves
- abducens
- oculomotor nerve
- trochlear
first and second divisions of the trigeminal
3rd, 4th, first and second divisions of the 5th, 6th
sinus in the groove between the petrous temporal bone and the basal part of the occipital bone
inferior petrosal sinus
emissary veins
allow communication between inter cranial venous sinuses and the veins outside the skull
consequences of venous sinus thrombosis
cerebral oedema and raised inter cranial pressure
brain damage
headaches, epileptic seizures, focal motor deficit, deterioration in consciousness
what are arachnoid granulations?
arachnoid granulations are pockets of arachnoid membrane and subarachnoid space which connect cerebrospinal fluid to venous circulation
what does the brain develop from?
hollow neural tube
where is most choroid plexus found?
lateral ventricles
what is choroid plexus and what is its function?
a network of blood vessels in each ventricle of the brain, producing the cerebrospinal fluid
what connects the lateral and second ventricle?
inter ventricular foramen of Munroe
what connects the third and fourth ventricle?
cerebral aqueduct
from the fourth ventricle, which foramina does CSF then travel to?
median foramen of magendie
lateral foramen of luschka
which cells line the ventricles?
ependymal cells
what constitutes the CSF-brain barrier?
the ependyma
which blood vessels supply the deep structures of the anterior part of the cerebral hemisphere?
anterior perforating branches
name the cranial fossae
anterior, middle and posterior
in which bone is the cribriform plate?
ethmoid
in which fossa is the frontal lobe contained?
anterior cranial fossa
which bones form the anterior cranial fossa?
frontal bone, ethmoid bone and sphenoid bone
what is the crista galli?
midline projection in the ethmoid bone
which wing of the sphenoid bone bounds the anterior cranial fossa posteriorly?
lesser
which lobes of the brain are contained in the middle cranial fossa?
temporal, parietal and occipital
list the cranial fossae in order from shallowest to deepest
anterior, middle, posterior
which fissure is between the greater and lesser wings of the sphenoid?
superior orbital fissure
in which bone is the optic canal?
sphenoid
which bones form the middle cranial fossa
sphenoid and two temporal bones
what is the sella turcica?
saddle-like bony formation on the upper surface of the body of sphenoid bone
houses the pituitary gland
also called the pituitary (hypophyseal) fossa
in which cranial fossa is the foramen rotundum?
middle
in which cranial fossa is the foramen ovale?
middle
in which cranial fossa is the foramen lacerum?
middle
in which cranial fossa is the foramen spinosum?
middle
what does the posterior cranial fossa contain?
cerebellum, pons and medulla oblongata
in which cranial fossa is the foramen magnum?
posterior
in which cranial fossa is the hypoglossal canal?
posterior
in which cranial fossa is the internal acoustic meatus (internal auditory meatus)?
posterior
what are the holes in the cribriform plate called?
olfactory foramina
in which cranial fossa is the jugular foramen?
posterior cranial fossa
which cranial nerves pass through the jugular foramen?
CN IX, X, XI
glossopharyngeal, vagus, accessory nerve
what passes through the jugular foramen?
CN IX, X, XI
internal jugular vein
what passes through the foramen magnum?
vertebral arteries
anterior and posterior spinal arteries
spinal cord
what passes through the internal acoustic meatus?
CN VII - facial
CN VIII - vestibulocochlear
what passes through the ethmoidal foramen?
CN I - olfactory
what passes through the optic canal?
CN II - optic
what passes through the superior orbital fissure?
CN III - oculomotor
CN IV - trochlea
CN VI - abducens
CN V(1) - trigeminal (ophthalmic branch)
what passes through the foramen rotundum?
CN V(2) - trigeminal (maxillary)
what passes through the foramen ovale?
CN V(3) - trigeminal (mandibular)
what passes through the hypoglossal canal?
CN XII - hypoglossal
raised intercranial pressure
caused by space occupying lesions (SOLs; tumour, haematoma, abscess) and idiopathic inter cranial hypertension
signs and symptoms
- headache
- nausea
- visual disturbance
- later, altered consciousness
- papilledema
- increased blind-spot on visual field testing
identify the muscles and nerves of the orbit
.
from which spinal segments and cranial nerves is parasympathetic outflow?
CN III - oculomotor
CN VII - facial
CN IX - glossopharyngeal
CN X - vagus
sacral spinal segments 2,3 and 4 - S2-4
where do parasympathetic fibres in the oculomotor nerve originate from?
Edinger-Westphal nucleus in the midbrain
where is the nucleus for the oculomotor nerve?
midbrain
Edinger-Westphal
which muscles does the oculomotor nerve innervate?
Superior rectus, inferior rectus, medial rectus, inferior oblique, levator palpebrae superioris, sphincter pupillae (parasympathetics), ciliary muscle (parasympathetics)
where is sympathetic outflow from the CNS?
T1-L2
the sympathetic trunk
which spinal segment provides sympathetic innervation to the orbit?
T1
which extra ocular muscles are not innervated by the oculomotor nerve?
superior oblique and lateral rectus
action of medial rectus
adducts the eye
action of lateral rectus
abducts the eye
action of superior rectus
elevates (primary)
intorts (secondarily)
adducts (tertiarily)
action of inferior rectus
depresses (primary)
extorts (secondarily)
adducts (tertiarily)
action of superior oblique
intorts (primary)
depresses (secondarily)
abducts (tertiarily)
action of inferior oblique
extorts (primary)
elevates (secondarily)
abducts (tertiarily)
what is intorsion of the eye?
rotating the top of the eye towards the nose
what is extortion of the eye?
rotating the top of the eye away from the nose
what is adduction of the eye?
moving the eye inwards
what is abduction of the eye?
moving the eye outwards
mnemonic to remember the actions of superior and inferior muscles of the eye
RAD SIN
rectus adducts (therefore oblique abducts)
superior intorts (inferior extorts)
mnemonic to explain the innervation of the extra ocular muscles
LR6 SO4
lateral rectus is innervated by abducens (CN VI)
superior oblique is innervated by trochlear (CN IV)
all other extraocular muscles are innervated by oculomotor
jugular foramen syndrome
compression of multiple lower cranial nerves
glossopharyngeal, vagus, accessory
symptoms
- dysphonia
- loss of gag reflex
- unilateral wasting of sternocleidomastoid and trapezius
foramen magnum syndrome
compression of spinal cord, lower brain stem or part of cerebellum
symptoms
- pain in head, neck, limbs, trunk made worse by straining
cerebellar symptoms: vertigo, gait disturbance
decerebrate posture
cardiorespiratory failure
pyramidal signs
death
Arnold-Chiari malformation
congenital
displacement of the cerebellar tonsils down through the foramen magnum
sometimes blocks CSF flow causing hydrocephalus
symptoms
- headaches
- fatigue
- muscle weakness in the head and face
- impaired coordination
label the ear
.
acoustic neuroma
benign tumour of myelin sheath of the vestibulocochlear nerve
components of the brainstem
midbrain
pons
medulla oblongata
what is the bulbopontine sulcus?
transverse groove at the caudal border of the pons
what is the basilar sulcus?
shallow sulcus on the ventral aspect of the pons in which the basilar artery runs
function of the cerebellar peduncles
connect the cerebellum to the different parts of the brainstem
function of the superior cerebellar peduncles
connect the cerebellum and midbrain
function of the middle cerebellar peduncles
connect the cerebellum to the pons
function of the inferior cerebellar peduncles?
connect the cerebellum to the medulla
what is the anterior median fissure?
division of the medulla in the ventral midline
what are medullary pyramids?
elongated eminences marking the position of underlying fibres passing from the cerebral hemisphere to the cord
what are the types of pyramidal tracts?
corticospinal and corticobulbar
where do the pyramidal tracts originate?
cerebral cortex
where do corticospinal tracts travel between?
cerebral cortex and spinal cord
where do corticospinal tracts terminate?
spinal cord
where do the corticobulbar tracts travel between?
cerebral cortex and (cranial nerve nuclei in the) brainstem
what are pyramidal tracts responsible for?
motor functions
what is the decussation of the pyramids?
point at the junction of the medulla and spinal cord where the motor fibers from the medullary pyramids cross the midline
what percentage of corticospinal tracts decussate?
80%
what percentage of corticobulbar tracts decussate?
50%
where is the ventrolateral sulcus?
lateral border of the pyramid on each side
where are the olives, and what are they?
lateral to the ventrolateral sulcus of the medulla
caused by the presence of the underlying olivary nucleus
involves with the control of movement
what are the corpora quadrigemina?
superior and inferior colliculi
function of the superior colliculi
visual reflexes
part of the visual system
function of the inferior colliculi
reflex of looking towards a loud noise
part of the auditory system
function of the pineal gland
endocrine gland that synthesises melatonin, which modulates sleep patterns
what is the inferior brachium?
conveys auditory information from the medial geniculate body (nucleus) to the inferior colliculi
what is the superior brachium?
conveys visual information from the lateral geniculate body (nucleus) to the superior colliculi
can the tectum be seen on the dorsal or ventral aspect of the midbrain?
dorsal
can the pineal gland be seen from the dorsal or ventral aspect of the midbrain?
dorsal
what is the rhomboid fossa?
floor of the 4th ventricle
which part of the brain can the floor of the 4th ventricle be seen?
dorsal aspect of the pons
which nuclei are found in the pontine tegmentum?
abducens
facial
motor division of trigeminal
5th, 6th and 7th
where does the tegmentum extend from?
substantia nigra to cerebral aqueduct
what marks the midline of the medulla?
posterior median sulcus
what are the gracile tubercles?
round swellings either side of the midline which overlie the gracile fasciculus
what is the gracile fasciculus?
carries fine touch, vibration, two-point discrimination and proprioception from the lower limb
what are the cuneate tubercles?
swellings lateral to the gracile tubercles which overlie the cuneate fasciculus
what is the cuneate fasciculus?
carries fine touch, vibration, two-point discrimination and proprioception from the upper limb
which nuclei are found in the medullary tegmentum?
glossopharyngeal, vagus, accessory, hypoglossal
9th, 10th, 11th and 12th
what are the nuclei underlying the gracile and cuneate tubercles also called?
dorsal column nuclei
what are the dorsal column nuclei?
major relay site for the dorsal column sensory pathway
i.e DCMLS - dorsal column medial leminscal system
Bell’s Palsy
acute unilateral inflammation of the facial nerve - lower motor neuron
if caused by herpes zoster, a vesticular rash is present in the external auditory canal and on the oropharynx
signs and symptoms
- pain behind ear
- paralysis of the facial muscles and failure to close eye
- absent corneal reflex
- hyperacusis
- loss of taste on anterior two-thirds of tongue
Bulbar Palsy
impairment of the functions of the cranial nerves that arise from the medulla
- glossopharyngeal
- vagus
- spinal and cranial accessory
- hypoglossal
9-12
symptoms
- dysphagia
- absent gag reflex
caused by MND
pseudo bulbar palsy
similar symptoms to bulbar palsy but the lesion is in the upper motor neurons e.g stroke or MS
central pontine myelinolysis
destruction of myelin in the pons
occurs when low sodium levels are corrrected too quickly
MALES mnemonic
medial geniculate body - auditory
lateral geniculate body - eyes (so visual) superior colliculus
which is the only cranial nerve to emerge from the dorsal aspect of the brain?
trochlear
which two cranial nerves emerge from the cerebrum?
CN I and CN II
which cranial nerve emerges from the midbrain?
trochlear
which cranial nerves emerge from the midbrain-pontine junction?
oculomotor
which cranial nerve emerges from the pons?
trigeminal
which cranial nerves emerges from the pontine-medulla junction?
abducens, facial, vestibulocochlear
which cranial nerves emerge from the medulla?
posterior to the olive: glossopharyngeal, vagus, accessory
anterior to the olive: hypoglossal
mnemonic to remember cranial nerves
oh, oh, oh, to touch and feel very good velvet ah heaven
mnemonic to remember component fibres of the cranial nerves
some say money matter but my brother says big brains matter more
s = sensory
m = motor
b = both
which cranial nerves are parasympathetic?
1973
10th, 9th, 7th, 3rd
vagus, glossopharyngeal, facial, oculomotor
what does the olfactory nerve innervate?
olfactory epithelium
what does the optic nerve innervate?
retina
what does the oculomotor nerve innervate?
extraocular muscles excluding lateral rectus and superior oblique
- superior rectus
- inferior rectus
- medial rectus
- inferior oblique
- levator palpebrae superioris
sphincter pupillae and ciliary muscle of the eye
function of levator palpebrae superioris
elevate upper eyelid
how can we remember which extraocular muscles are not innervated by oculomotor?
LR6 SO4
lateral rectus = 6th cranial nerve
superior oblique = 4th cranial nerve
what does the trochlear nerve innervate?
superior oblique
what does the sensory component of the trigeminal innervate?
face, scalp, cornea, nasal and oral cavities
what does the motor component of the trigeminal innervate?
muscles of mastication, tensor tympani
name the divisions of the trigeminal in order
ophthalmic (V1)
maxillary (V2)
mandibular (V3)
oh max man
which division of the trigeminal is the only one to receive motor fibres?
mandibular
what does abducens innervate?
lateral rectus
what does the facial nerve innervate?
sensory, motor and parasympathetic
sensory
- anterior 2/3 of tongue
motor
- muscles of facial expression
parasympathetic
- salivary and lacrimal glands via submandibular and pterygopalatine gland
what does the vestibulocochlear innervate?
vestibular apparatus
cochlear
what does the glossopharyngeal innervate?
sensory, motor and parasympathetic
sensory
- posterior third of tongue
- pharynx
- Eustachian tube
- middle ear
motor
- stylopharyngeus muscle
parasympathetic
- parotid salivary gland
sensory innervation of the vagus
pharynx, larynx, trachea, oesophagus, external ear
thoracic and abdominal viscera, aortic bodies, aortic arch
motor innervation of the vagus
soft palate, pharynx, larynx, upper oesophagus
parasympathetic innervation of the vagus
thoracic and abdominal viscera
what does the accessory nerve innervate?
sternocleidomastoid and trapezius muscle
what does the hypoglossal nerve innervate?
intrinsic and extrinsic muscles of the tongue
function of the olfactory nerve
olfaction
function of the optic nerve
vision, pupillary light reflex
function of the oculomotor nerve
movement of the eyeball
elevation of the upper eyelid
pupillary constriction and accommodation
function of the trochlear
intorts the eye
function of the trigeminal nerve
general sensation of the face, scalp, cornea, nasal and oral cavities
opening and closing the mouth
function of abducens
ABducts the eye
ABducens ABducts
function of the facial nerve
taste, facial movement, salivation and lacrimation
function of the vestibulocochlear nerve
vestibular sensation
(position/ movement of head) hearing
function of the glossopharyngeal nerve
general sensation to the pharynx, posterior third of tongue, Eustacian tube, middle ear
swallowing
salivation
function of the vagus nerve
general sensation
visceral sensation
chemoreception
baroreceptors
speech
swallowing
innervation of cardiac muscle, smooth muscle and glands of CVS system, respiratory and GI tracts
function of the accessory nerve
movement of head and shoulder
function of hypoglossal
movement of tongue
which are the only two cranial nerves to pass through canals?
cranial nerves with a 2 in them
2nd and 12th
optic nerve and hypoglossal nerve
pass through a canal of the same name
what passes through the cribriform plate?
olfactory nerve
which nerve passes through the optic canal?
optic nerve
which nerves pass though the superior orbital fissure?
3rd, 4th, first division of the 5th, 6th
oculomotor
trochlear
ophthalmic division of the trigeminal
abducens
these are all intuitive since they act on the eye
in which bone is the superior orbital fissure?
sphenoid
which nerve passes through the foramen rotundum?
second division of the 5th (maxillary division of the trigeminal)
CNV2
which nerve passes through the foramen ovale?
third division of the 5th (mandibular division of the trigeminal)
CNV3
which nerve passes through the internal acoustic meatus?
facial
vestibulocochlear
which nerve passes through the jugular foramen?
9th, 10th and 11th
glossopharyngeal, vagus, accessory
which nerve passes through the hypoglossal canal?
hypoglossal
what do the fibres from the nasal portion of the retina provide information about?
temporal visual field
do fibres from the nasal or temporal retina cross?
nasal
where do fibres from the nasal retina cross?
optic chiasma/ optic chiasm
what do the optic nerves become after the optic chiasma?
optic tracts
where do the optic tracts terminate?
lateral geniculate bodies of the thalamus
but some continue medially to the midbrain (pretectal nucleus and superior colliculus) where they synapse to form the afferent limb of the visual reflexes
where do axons of the nerve cells from the lateral geniculate pathways pass?
posteriorly through the internal capsule to the visual cortex of the occipital lobe
what does the inferior portion of the retina supply information about?
superior visual field
which lobes do the fibres carrying information from the inferior portions of the retina (superior visual field) to the visual cortex pass through?
temporal lobe
which lobes do the fibres carrying information from the superior portions of the retina (inferior visual fields) pass through on the way to the visual cortex?
parietal lobe
what can a pituitary tumour cause and why?
bitemporal hemianopia
impaired vision in the outer temporal halves of the visual field of each eye
due to pressing on the optic chiasma
what are Meyer’s loops?
optic tracts from the lower retina (superior visual field) passing through the temporal lobes to travel to the visual cortex in the occipital lobe
what will damage to the Meyer’s loops cause?
upper quadrantinopia
what will damage to the neurons travelling from the lateral geniculate body to the occipital lobe via the parietal lobe cause?
lower quadrantinopia
what does a lesion of the optic tract after the optic chiasm cause?
homonymous hemianopia
vision loss on the same side of the visual field in both eyes
which cranial nerves pass through the cavernous sinus?
CN III, CN IV, CNV1, CNV2, CN VI
what ridges does the cerebellum have on the surface?
folia
function of the cerebellum
coordination of movement and balance
what joins the cerebellar hemispheres?
vermis
where is grey matter located in the brain?
outside
where is grey matter located in the spinal cord?
inside
cerebellar cortex
outer layer of grey matter
what shape do the cerebellar peduncles form?
clef
or bottom of golf stick
what is the red nucleus and where is it found?
circular mass of grey matter ventro-lateral to the cerebral aqueduct in the midbrain
what is the substantia nigra and where is it found?
black band of nerve cells overlying the crus cerebri
ventrolateral to the red nucleus on each side in the midbrain
which fissures does the cerebellum have?
horizontal and primary fissures
which lobes does the cerebellum have?
anterior and posterior
what divides the cerebellum into its respective lobes?
primary fissure
prominent rounded swellings on the cerebellar cortex anteriorly on either side of the vermis
tonsils
ovoid swelling lying immediately posterior to the lateral foramen of the 4th ventricle on each side
flocculus
what is continuous with the flocculus via a peduncle of white matter?
nodule
what is the flocculo-nodular lobe and its function?
flocculus and nodule together, primarily concerned with vestibular information
what connects the cerebellum to the medulla?
inferior cerebellar peduncle
what connects the cerebellum to the pons?
middle cerebellar peduncle
hat connects the cerebellum to the midbrain?
superior cerebellar peduncle
which is the largest and most lateral of the deep cerebellar nuclei?
dentate nucleus
where is the dentate nucleus?
in the cerebellar peduncles
which part of the brainstem is at the same level as the cerebellum?
pons
what limits the rhomboid fossa laterally?
cerebellar peduncles
what limits the rhomboid fossa posteriorly?
gracile and cuneate tubercles
what is the gracile fasciculus?
medial dorsal columns carrying touch, vibration, two-point discrimination and proprioception from the lower limb
a bundle of nerve fibres
what is the cuneate fasciculus?
lateral dorsal colums carrying touch, vibration, two-point discrimination and proprioception from the upper limb
a bundle of nerve fibres
medan sulcus
divides the rhomboid fossa into triangular left and right halves
area postrema
where and function
small tongue shaped area immediately rostro-lateral to the obex
nausea control
label the brainstem and floor of the 4th ventricle
rhomboid fossa
gracile tubercles
cuneate tubercles
median sulcus
median sulcus
facial colliculus
medullary striae
locus coeruleus
hypoglossal trigone
vagal trigone
vestibular trigone
obex
area postrema
what is the facial colliculus?
rounded swelling caused by the fibres of the facial nerve in the substance of the pons curving around the nucleus of the abducens nerve at the level of the superior fovea
what is the hypoglossal trigone
medial triangular area overlying the hypoglossal nerve nucleus
what is the vagal trigone?
intermediate triangular area overlying the vagus nerve nucleus
what is the vestibular trigone?
lateral triangular area overlying the vestibulocochlear nerve nucleus
what is the obex?
inferior apex of the rhomboid fossa
what is the paracentral lobule, and what does it represent?
U shaped gyrus surrounding the medial extension of the central sulcus which contains the representations of the lower limb within the primary motor and somatic sensory areas of the cortex, which on the lateral surface, occupy the pre-central and post-central gyri respectively
what is the cingulate gyrus?
gyrus wrapping around the corpus callosum
what is the cingulate sulcus?
separates the cingulate gyrus from the rest of the hemisphere
on which aspect of the hemisphere can the parieto-occipital sulcus mainly be seen?
medial
forms a Y shaped arrangement with the calcarine sulcus
the primary visual cortex lies in the walls of which sulcus?
calcarine
is the grey matter thicker in the primary motor or primary somatosensory cortex?
thicker in the primary motor cortex
in the homunculus, are the legs and feet represented medially or laterally?
medially
in the homunculus, is the face represented medially or laterally?
laterally
largest fibre bundle connecting the halves of the brain
corpus callosum
name the parts of the corpus callosum, first to last
rostrum, genu, body, isthmus, splenium
what and where is the fornix
bundle of white matter beneath the body of the corpus callosum
function of the fornix
connect the hippocampus to various subcortical structures
what is the anterior commisure?
thick bundle of white matter crossing the midline horizontally
connects the temporal lobes and olfactory structures of each side
which pathways is the anterior commisure involved in?
olfactory
where is the septum pellucidum?
between the corpus callosum and the fornix
where is the anterior commisure in a cross section?
sort of continuous with the rostrum of the corpus callosum
where is the lamina terminalis?
extends downwards from the rostrum of the callosum and fornix to the anterior wall of the 3rd ventricle
what is the dorsal part of the diencephalon?
thalamus
what is the ventral part of the diencephalon?
hypothalamus
intuitive - ‘hypo’ = under
function of the thalamus
major subcortical relay for information ascending to the cerebral cortex
where and what is the interthalamic adhesion?
flattened grey disc joining the thalami of each side behind the interventricular foramen
what divides the diencephalon into dorsal and ventral parts, and where is it?
hypothalamic sulcus
lateral wall of the third ventricle
function of the medial geniculate nucleus/ body
relays auditory information from the midbrain to the auditory cortex and passes some fibres via the inferior brachium to the inferior colliculi
function of the lateral geniculate nucleus/ body
relays visual information from the optic nerve to both the visual cortex via the optic radiation (for vision) and the superior colliculi via the superior brachium (for pupillary reflexes)
function of the lateral geniculate nucleus/ body
relays visual information from the optic nerve to both the visual cortex via the optic radiation (for vision) and the superior colliculi via the superior brachium (for pupillary reflexes)
which brachium and geniculate body are the superior colliculi related to?
superior brachium
lateral geniculate body
which brachium and geniculate body are the inferior colliculi related to?
inferior brachium
medial geniculate body
function of the hypothalamus
homeostasis
autonomic nervous and neuroendocrine systems control
ventral part of the diencephalon below the thalamus and lateral to the hypothalamus, merging posteriorly with the tegmentum
sub thalamus
what part of the diencephalon is the preoptic area, on functional grounds?
hypothalamus
association fibres
link cortical regions within one cerebral hemisphere
commissural fibres
link similar functional areas of the two hemispheres
projection fibres?
link the cortex with subcortical structures
give examples of subcortical structures
diencephalon, pituitary gland, limbic structures and the basal ganglia
is the diencephalon above or below the midbrain?
above
what type of fibre is the corpus callosum?
commissural
what type of fibre is the internal capsule and corona radiata?
projection
functions of the left hemisphere
verbal
linguistic description
mathematical
sequential
analytical
direct link to consciousness
functions of the right hemisphere
almost nonverbal
musical
geometriical
spatial comprehension
temporal synthesis
link to consciousness?
function of the limbic system
projects meaning on the external world
essential for adaptive behaviour, emotional responsiveness and the ability to learn new responses based on previous experiences
what system is related to the limbic system?
olfactory
why is the limbic system named so?
the main parts are located on the edge or ‘limbus’ of the hemisphere
how are the parts of the limbic system connected?
the Papez circuit
list the parts of the limbic system
cingulate gyrus, hippocampal formation, parahippocampal gyrus, anterior perforated substance, septal nuclei, uncus, amygdala
also the parts of the diencephalon
- thalamus
- hypothalamus
- epithalamus
- subthalamus
what lies immediately dorsal and parallel to the corpus callosum?
cingulate gyrus
what is the parahippocampal gyrus continuous with?
cingulate gyrus
what lobe is the parahippocampal gyrus in?
temporal
what is the uncus
hook shaped region of cortex at the anterior end of the temporal lobe
role of the uncus
olfaction, emotions and memory
what is the longest association fibre bundle?
superior longitudinal fasciculus
what is the corona radiata continuous with below?
internal capsule
in which lobe is the anterior horn of the lateral ventricle?
frontal
what forms the roof and anterior wall of the lateral ventricle?
body and genu of the corpus callosum
what forms a bulge in the infero-lateral aspect of the anterior horn of the lateral ventricle?
caudate nucleus
what forms the medial wall of the lateral ventricle?
fornix and septum
action of superior oblique
moves the eye down and out
what is the stria terminalis?
slender bundle of white fibres accompanying the curve of the caudate into the temporal horn of the ventricle and connecting the amygdala with the septum and hypothalamus
which lobes do the lateral ventricles project into?
frontal, temporal, and occipital lobes
which horns does the lateral ventricle have?
anterior, inferior and posterior
in which lobe is the inferior horn of the lateral ventricle?
temporal
where is the amygdaloid body?
tip of the inferior horn
temporal lobe
in which lobe is the hippocampus?
temporal
efferent fibres from the hippocampus heading to the fornix
fimbria
in which lobe is the posterior horn of the lateral ventricle?
occipital
hydrocephalus
blockage of CSF flow in ventricles e.g tumours or subarachnoid space leads to rise in fluid pressure causing the ventricles to swell
relieved by inserting a shunt connecting the ventricular system to the peritoneum or jugular vein
symptoms
- raised intercranial pressure
- headache
- unsteadiness
- mental impairment
what forms the striatum?
caudate nucleus and putamen
what forms the lentiform nucleus?
putamen and globus pallidus
what is the claustrum?
part of basal ganglia
subcortical nucleus derived from the telencephalon
receives from and projects to the cerebral cortex in a topographically organised manner
contains cells that respond to visual, auditory and sensory stimuli
what is the extreme capsule?
white matter connecting the claustrum and insular cortex
what is between the extreme capsule and external capsule?
claustrum
what is between the insular cortex and claustrum?
extreme capsule
what does the corona radiata continue as inferiorly?
internal capsule
what separates the putamen and globus pallidus?
lateral medullary lamina
what separates the lateral and medial parts of the globus pallidus?
medial medullary lamina
what carries all the motor and sensory fibres from and to the cortex?
internal capsule
name the parts of the corpus callosum from anterior to posterior?
rostrum, genu, body, isthmus, splenium
really good bodies in Spain
what is the caudate nucleus?
paired, “C”-shaped subcortical structure which lies deep inside the brain near the thalamus
Parkinson’s disease
degenration of dopaminergic neurones of the Substantia nigra
depletion of striatal dopamine levels
symptoms
- pill rolling tremor at rest
- cog-wheel rigidity
- bradykinesia
neurology of Huntington’s
degeneration of the corpus striatum and cerebral cortex
ow many cervical vertebrae?
7
how many thoracic vertebrae?
12
how many lumbar vertebrae?
5
how many vertebrae fuse to form the sacrum?
5
how many coccygeal vertebrae fuse to form the coccyx?
4
what joins the spine and the pelvis?
sacroiliac joints
label a vertebrae
.
uppermost palpable spinous process
C7
higest point of iliac crest
between L3 and L4
movements of the vertbral column
forward flexion (40 degrees)
extension (15 degrees )
lateral flexion (30 degrees)
rotation (40)
where is rotation maximum?
thoracic region
where is rotation limited?
lumbar
re are flexion and extension limited?
thoracic due to ribcage
layers of intervertebral discs
nucleus pulposus surrounded by annulus fibrosis
sciatic nerve
L5
space between dura mater and vertebrae
epidural space
how many spinal nerve pairs?
31
many spinal cord segments?
31
how many cervical spinal segments?
8
not 7 as you might think
how many thoracic spinal cord segemtns
12
how many lumbar spinal cord segemtns?
5
how many sacral spinal cord segments?
5
how many coccygeal spinal cord segments?
1
where do spinal nerves exit the spinal canal?
intervertebral foramen
lumbar and sacral nerve roots below the termination of the cord
cauda equina
which joints are between vertebrae?
plane synovial
where does the spinal cord end?
between L1 and L2
bel the main spinal cord tracts
.
is the ventral root motor or sensory?
motor
is the dorsal root motor or sensory?
sensory
function of the ligamentum flavun
connect the ventral parts of the laminae of adjacent vertebrae
