Week 6 - Brainstem and Venous Drainage Flashcards
What are the 3 parts of the brainstem inferior to superior?
- Medulla Oblongata
- Pons
- Midbrain
What are the anatomical relations of the medulla oblongata?
What cranial nerves is it associated with?
What centres does it contain?
- most caudal portion of brainstem and brain, and below the pons
- associated with cranial nerves IX, X, XI, XII
- contains respiratory, cardiac and vasomotor centres
What are the anatomical relations of the pons?
What cranial nerves is it associated with?
What functions is it involved in?
- central portion of brainstem between midbrain and medulla oblongata (“pons” latin for: bridge)
- associated with cranial nerves V, VI, VII, VIII
- involved in control of sleep and respiration
What are the anatomical relations of the midbrain?
What cranial nerves is it associated with?
What functions is it involved in?
- between diencephalon and pons
- associated with cranial nerves III and IV
- composed of white matter tracts and grey matter nuclei; coordinates movements in response to visual and auditory stimuli. Conveys motor information from cerebral cortex to pons. Conveys sensory information from spinal cord to thalamus
What are prominent features of the midbrain?
superior and inferior colliculi (visual and auditory reflex centres) cerebral peduncle/crus cerebri substantia nigra red nucleus cerebral aqueduct interpeduncular fossa
What are prominent features of the pons?
rhomboid fossa - forming floor of 4th ventricle
bulbopontine sulcus
basilar sulcus
middle cerebellar peduncles
What are prominent features of the medulla oblongata?
olive pyramid decussation of pyramids nucleus gracilis and cuneatus anterior median fissure ventrolateral sulcus
At the level of the rostral medulla - what is the function of the inferior cerebellar peduncle/restiform body? Where is it located?
- most dorsolateral part
- consists of fibres passing between the medulla and cerebellum
- includes - olivocerebellar fibres (connects vestibular nuclei and cerebellum)
- includes - dorsal spinocerebellar tract (conveys proprioceptive information from lower limb)
At the level of the rostral medulla - what is the function of the nucleus solitarius? Where is it located?
- medial to inferior cerebellar peduncles and ventral to vestibular nuclei
- surrounds a small, dense fascicle of fibres called the solitary tract
- nucleus solitaris receives visceral afferent fibres entering the brainstem in the facial (CNVII), glossopharyngeal (CNIX) and vagus (CNX) nerves
At the level of the rostral medulla - what is the function of the nucleus ambiguus? Where is it located?
- deep to ventricular floor and ventral to nucleus solitarius. dorsal to inferior olivary nucleus
- sends motor fibres into glossopharyngeal (CNXI) and vagus (CNX) nerves, and cranial roots of the accessory (CNXI) nerve (therefore muscles of the pharynx and larynx)
At the level of the mid medulla - what is the function of the gracile and cuneate nuclei?
the termination point for ascending fibres (1st order neurons) of the dorsal columns
2nd order neurons continue on to medial lemniscus.
At the level of the mid medulla - what is the function of the medial lemniscus?
runs through the brainstem (rostral medulla, pons and midbrain) to terminate on 3rd order neurons in the ventral posterior nucleus of the thalamus
At the level of the caudal medulla - what is the function of the trigeminal sensory nucleus? Where is it located?
- dorsal medulla contains both nuclei and spinal tract of trigeminal. large nucleus extending the whole length of the brainstem and into the upper segments of the spinal cord
- regarded at brainstem homologue of dorsal horn
- receives primary afferent fibres conveying general sensation from head entering the brainstem as CNV
- caudal portion of the trigeminal nucleus particularly associated with modalities of pain and temperature
At the level of the mid medulla - what is the function of the decussation of the pyramids?
in the ventral medulla, majority of the pyramids undergo decussation - crossing over. They pass laterally and dorsally and caudally to form the lateral corticospinal tract
At the level of the rostral medulla - what is the function of the inferior olivary nucleus?
Dorsolaterally located
nucleus focus:
- control of movement
- afferent from motor and sensory cortices of cerebral hemisphere and red nucleus from midbrain
- main efferent fibres connect cerebellum via inferior cerebellar peduncle
At the level of the pons - what is the function of the pontine nuclei?
give off transversely oriented fascicles of pontocerebellar fibres that pass contralaterally via middle cerebellar peduncle to opposite cerebellar hemisphere.
At the level of the pons - what is the function of the trapezoid body?
consists of acoustic fibres that cross the brainstem from the cochlear nuclei
ascend into the midbrain at the lateral lemniscus, terminating in the inferior colliculus
What nuclei are found below the floor of the 4th ventricle in the pontine tegmentum?
Abducens - innervates lateral rectus muscle
Facial Motor - innervates muscles of facial expression
Trigeminal Motor - innervates muscles of mastication
Where is the superior cerebellar peduncle located?
What kind of fibres does it contain? What do they convey?
In the rostral half of the pons, forming the lateral walls of the 4th ventricle
ventral spinocerebellar tract - convey proprioceptive information from lower limb and efferent fibres ascending from the cerebellum which coordinate movement. They are destined for the red nucleus of the midbrain and ventral lateral nucleus of the thalamus
At the level of the midbrain - what is the function of the superior colliculus?
Is part of the visual reflex centre
corticotectal fibres from the visual cortex of the occipital lobe and the frontal eye field of the frontal lobe are involved in the accommodation reflex
inputs concerned with controlling movements of the eyes, e.g. when following a moving object with eyes (smooth pursuit) or altering direction of gaze (saccadic eye movement)
What is the function of the Edinger-Westphal Nucleus?
controls the smooth muscle of the eye and is part of the circuit mediating the pupillary light reflex
At the level of the midbrain - what is the function of the inferior colliculus?
Is part of the auditory reflex centre
At the level of the midbrain - what is the nuclei subdivisions of the substantia nigra? Where is it located?
Ventral-most part of the midbrain
2 types of subnuclei - pars compacta and pars reticulata
What is the function of pars compacta?
What pathology is degeneration associated with?
pigmented, melanin-containing neurons
synthesis dopamine
project neurons to caudate nucleus and putamen of basal ganglia - nigrostriatal pathway
controls voluntary movement, posture and muscle tone
degeneration associated with Parkinson’s
What is the function of pars reticulata?
non-pigmented subdivision
functional homologue of internal segment of globus pallidus
shares very similar connections as pars compacta
What is the function of the medial longitudinal fasciculus in the midbrain?
links oculomotor and Edinger-Westphal nuclei to abducens nucleus (in pons) and vestibular nucleus (in medulla)
functions to help control gaze
What is the function of the red nucleus in the midbrain?
motor control
major source of afferents from motor cortex in frontal lobe
efferent fibres from the red nucleus cross in the ventral tegmental decussation and descend into the spinal cord via the rubrospinal tract
projects to the inferior olivary nucleus of the medulla via the central tegmental tract
What is the function of crus cerebri in the midbrain?
made up entirely of descending cortical efferent fibres from cerebral hemisphere by traversing the internal capsule
around the middle 50% of the crus cerebri consists of corticobulbar and corticospinal fibres
either side of this corticopontine fibres originating in the cerebral cortex travel to the pontine nuclei of the ventral pons
Where is the dentate nucleus found? What is it’s function?
The dentate nuclei are located deep within the lateral hemispheres
They receive the majority of their input from the lateral hemispheres
(dentate - has a tooth-like/serrated edge)
Name the 4 deep cerebellar nuclei
dentate
emboliform
fastigial
globose
What are the inputs and outputs of the deep cerebellar nuclei?
They receive projections from mossy fibers and climbing fibers
The nuclei receive inhibitory GABAergic input from the Purkinje cells
The nuclei receive excitatory input from the mossy and climbing fibers
The majority of the output from the cerebellum arises from these nuclei
What are symptoms of cerebellar diseases?
- dysarthria - slurring of speech/inappropriate phrasing and/or articulating words correctly
- ataxia - unsteady gait
- asynergia - inability to combine motions into fluid movement
- nystagmus - involuntary and rhythmic to and fro motion of eyes
- dysdiadochokinesia - inability to perform rapid alternating movements
- dysmetria - inability to control range of movement
- hypotonia - decreased muscle tone
- scanning speech - slow enunciation with tendency to hesitate at beginning of a word/syllable
- tremor - oscillating movement, can be intention or postural tremor
What is the tectum? Where is it found?
The posterior region of the midbrain, dorsal to the cerebral aqueduct
The roof of the midbrain
Contains two pairs of sensory nuclei - superior and inferior colliculi
Collectively called - tectal place
What is the tegmentum? Where is it found?
sandwiched between substantia nigra and periaqueductal gray matter in the midbrain
contains red nuclei and reticular formation
What causes the red colour in the red nucleus?
blood vessel density
iron pigmentation in neuronal cell bodies
What is the rhomboid fossa?
forms the floor of the fourth ventricle of the brain
is formed by the dorsal surfaces of the pons and medulla oblongata
What is the difference between direct and indirect descending spinal pathways?
direct = conscious skilled movements indirect = unconscious movements
Name two direct descending spinal pathways
What are the functions they control? Give an example
Corticospinal tract - lateral and anterior
movements below the head, especially of the hands
lateral - neck, trunk and limbs, e.g. push-ups, moving with a hula hoop
anterior - neck and upper limb extremities, e.g. typing
Corticobulbar tract
movements of the head and face, e.g. facial expression, chewing
What is the origin of the direct descending spinal pathways?
cerebral cortex
What is the pathway of the lateral corticospinal tract?
- originates from cerebral cortex
- crossover at inferior end of medulla oblongata
- terminates in anterior horn of spinal cord
- innervates contralateral side of body
What is the pathway of the anterior corticospinal tract?
- originates from cerebral cortex
- crossover at level of lower motor neuron
- terminates in anterior horn of spinal cord
- innervates contralateral side of body
What is the pathway of the corticobulbar tract?
- originates from cerebral cortex
- crossover varies depending on the cranial nerve
- terminates in cranial nerve nuclei in brainstem (lower motor neuron)
- innervates contralateral side of body
Name four indirect descending spinal pathways
What are the functions they control? Give an example
Rubrospinal - movement coordination, e.g. positioning of digits and palm of hand when reaching out to grasp
Vestibulospinal - maintenance of upright posture and balance, e.g. extension of upper limbs when falling
Reticulospinal - posture adjustment, walking, e.g. maintenance of posture when standing on one foot
Tectospinal - movements of head and neck in response to visual and auditory reflexes, e.g. movement of head and neck away from a sudden flash of light
What is the pathway of the rubrospinal tract?
- originates at the red nucleus
- crossover at the midbrain
- terminates in the anterior horn of spinal cord
- innervates contralateral side of body
What is the pathway of the vestibulospinal tract?
- originates at the vestibular nucleus
- doesn’t cross over (uncrossed)
- terminates in the anterior horn of spinal cord
- innervates ipsilateral side of body
What is the pathway of the reticulospinal tract?
- originates at the reticular formation
- some crossover at termination; others uncrossed
- terminates in the anterior horn of spinal cord
- innervates contralateral or ipsilateral side of body (depending if crossed over or not)
What is the pathway of the tectospinal tract?
- originates at the superior colliculus
- crossover at the midbrain
- terminates in the cranial nerve nucleus in medulla oblongata and anterior horn of upper levels of spinal cord (lower motor neurons that turn the head and neck)
- innervates contralateral side of body
What are the four types of ascending spinal pathways?
Anterolateral
Dorsal-column medial-lemniscal (DCML)
Spinocerebellar
Spinoolivary
What are the three types of anterolateral ascending spinal pathways?
What are their modality (information transmitted)?
Spinothalamic - pain, temperature, light touch, pressure, tickle and itch
Spinoreticular - pain
Spinomesencephalic (including spinotectal) - pain and touch
What is the origin, primary and secondary cell bodies of the anterolateral pathway?
What side of the body does all three pathways innvervate?
origin - cutaneous receptors
primary cell body - dorsal root ganglion
secondary cell body - posterior horn of spinal cord
innervates contralateral side
Spinothalamic Tract
- what is the point of crossover?
- what is the tertiary body?
- what is the termination point?
crossover - level at which the primary neuron enters the spinal cord for pain and temperature. or 8-10 segments from where the primary neuron enters spinal cord for light touch
tertiary body - thalamus
termination - cerebral cortex
Spinoreticular Tract
- what is the point of crossover?
- what is the tertiary body?
- what is the termination point?
crossover - reticular formation
tertiary body - reticular formation
termination - reticular formation and thalamus
Spinomesencephalic Tract
- what is the point of crossover?
- what is the tertiary body?
- what is the termination point?
crossover - point of origin
tertiary body - superior colliculus
termination - mesencephalon and superior colliculus
Describe the Dorsal-Column Medial Lemniscal (DCML) tract
origin, primary/secondary/tertiary cell bodies, point of crossover, termination, side of body of termination
origin - joints, tendons, muscles primary body - dorsal root ganglion secondary body - medulla oblongata crossover - medulla oblongata tertiary body - thalamus termination - cerebral cortex and cerebellum side of body - contralateral side
Spinocerebellar Tract
What are the two divisions of this tract?
Describe the tract (origin, primary/secondary/tertiary cell bodies, point of crossover, termination, side of body of termination)
Posterior and Anterior
origin - joints and tendons
primary body - dorsal root ganglion
secondary body - posterior horn of spinal cord
tertiary body - cerebellum
crossover - uncrossed (anterior - some cross a point of entry; recross at cerebellum)
termination - cerebellum
side of body - ipsilateral
Describe the Spinoolivary tract
origin, primary/secondary/tertiary cell bodies, point of crossover, termination, side of body of termination
origin - joints and tendons
primary body - dorsal root ganglion
secondary body - posterior horn of spinal cord
tertiary body - accessory olivary nucleus
crossover - crossed at point of entry; recross to reach cerebellum
termination - accessory olivary nucleus, then cerebellum
side of body - ipsilateral
What is a discriminative ascending pathway responsible for?
Give an example?
sensory - fine touch, vibration, two-point discrimination, proprioception
e.g. dorsal-column medial lemniscal (DCML) tract
What is a reactive ascending pathway responsible for?
Give an example?
sensory - pain, temperature, crude touch
e.g. spinothalamic tract
What is Wallenberg Syndrome?
What are the symptoms?
a rare condition where infarction or stroke occurs in the lateral medulla
symptoms - dysphagia, dizziness, hoarseness of voice, nausea and vomiting, problems with balance and gait, uncontrollable hiccups, loss of pain/temperature sensation on one side of face/weakness in one side of body
What are the cerebellar afferent pathways?
olivocerebellar vestibulocerebellar reticulocerebellar corticopontocerebellar trigeminocerebellar
What are the cerebellar efferent pathways?
cerebellovestibular cerebelloreticular corticonuclear cerebellothalamic cerebellorubral
Describe the olivocerebellar pathway
- climbing fibers from olivary nucleus decussate to reach the opposite Raphe nucleus
- these fibers pass on as internal arcuate fibers
- these go on through the inferior peduncle to the opposite cerebellar hemisphere
Describe the trigeminocerebellar pathway
- ascending mossy fibers travel to the cerebellum via the inferior cerebellar peduncle
- they transmit proprioceptive information from the face to the cerebellum
Describe the cerebellothalamic pathway
- fibers arise from the cerebellar dentate nucleus passing through the superior cerebellar peduncle
- fibers decussate to terminate in the ventral anterior nucleus of the thalamus
What are the major arterial components of the Circle of Willis?
vertebral a. anterior spinal a. basilar aa. pontine aa. superior cerebellar a. posterior cerebral a. posterior communicating a. internal carotid a. middle cerebral a. anterior choroidal a. ophthalmic a. anterior cerebral a. anterior communicating a.
Describe the arterial pathway from the arch of aorta to anterior and middle cerebral arteries
Arch of aorta
- > right - brachiocephalic trunk - right common carotid a.
- > left - left common carotid a.
common carotid a. -> external and internal carotid a.
lateral to optic chiasm internal carotid divides into two terminal branches: anterior and middle cerebral aa.
Ophthalmic Artery
- what path does it follow?
- what structures does it supply?
passing into the orbit through the optic foramen
supplies structures of the orbit; frontal and ethmoidal sinuses; frontal part of the scalp; and dorsum of the nose
Anterior Choroidal Artery
- what structures does it supply?
optic tract
choroid plexus of lateral ventricle
hippocampus
some deep structures of the hippocampal hemisphere including the internal capsule and globus pallidus
Anterior Cerebral Artery
- what path does it follow?
- what structures does it supply?
courses medially above the optic nerve then passes into great longitudinal fissure between frontal lobes of the cerebral hemisphere
as it does this it is joined by the anterior communicating a.
within the great longitudinal fissure the artery follows the dorsal curvature of the corpus callosum
supplies medial surfaces of frontal and parietal lobes, includes motor and sensory cortices of lower limb
Middle Cerebral Artery
- what path does it follow?
- what structures does it supply?
passes laterally from its origin from internal carotid a.
it branches to supply virtually the whole of the lateral surface of the frontal, parietal and temporal lobes, including the primary motor and sensory cortices for the whole body (excluding lower limb)
supplies auditory cortex and the insula within the depths of the lateral fissure
Vertebral Artery
- what is its origin?
- what path does it follow?
- what structures does it supply?
- what branches does it give off?
arises from subclavian artery
ascends through foramina transversaria of cervical vertebrae
enters cranium through foramen magnum alongside the ventrolateral aspect of the medulla
two vertebral arteries converge at the junction of the medulla and pons to form basilar artery
posterior inferior cerebellar artery - branches before converging and supplies the inferior aspect of the cerebellum
anterior and posterior spinal arteries
Basilar Artery
- where is it located?
- what branches does it give off?
runs the length of the pons
branches:
- many small pontine branches - supplies pons
- anterior inferior cerebellar artery - which supplies the anterior and inferior cerebellum
- labyrinthine artery - passes into internal acoustic meatus to supply internal ear
At junction of pons and midbrain what two branches does the basilar artery divide into?
superior cerebellar arteries
posterior cerebral arteries
What does the superior cerebellar arteries supply?
superior aspect of the cerebellum
Posterior Cerebral Arteries
- what path does it follow?
- what does it supply?
curves around the midbrain
supplies the visual cortex of the occipital lobe and the inferomedial aspect of the temporal lobe
What is the function of the posterior communicating arteries?
To connect the internal carotid and vertebrobasilar systems
these pass rostrocaudally between the ends of the internal carotid arteries and posterior cerebral arteries
Why is the circle of Willis functional and clinically important?
the anastomotic arrangement of vessels can make allowances for compensating blood flow in the event of obstruction or narrowing of an artery via the communicating arteries
circle of Willis arteries give rise to perforating arteries which supply different regions of the brain
What do the anterior perforating arteries arise from? What do they supply?
arise from anterior cerebral artery, anterior communicating a. and the originating region of the middle cerebral artery
enter the brain in the region between optic chiasm and termination of the olfactory tract
supply large parts of the basal ganglia, optic chiasm, internal capsule and hypothalamus
What do the posterior perforating arteries arise from? What do they supply?
arise from posterior cerebral and posterior communicating arteries
enter the brain in the region between the two crura cerebri of midbrain
supply the ventral portion of midbrain and parts of the subthalamus and hypothalamus
What disorders can lead to neurological damage or deficits?
- stroke - blockage or rupture of vessels
- cerebral haemorrhage - rupture of blood vessels
- aneurysm - abnormal, balloon-like swelling of an artery that can rupture
- angioma (arteriovenous malformation) - congenital collection of swollen blood vessels that can rupture
What is an infarction?
sudden occlusion of a cerebral artery leading to death of brain tissue
What are the three types of epidural haematoma?
temporal fossa haematoma - likely damage to middle meningeal artery
subfrontal haematoma
posterior fossa haematoma
What are the symptoms of a subfrontal haematoma?
headache
poor cerebration
intermittent disorientation
anisocoria (unequal size of pupils)
What are the symptoms of a posterior fossa haematoma?
headache
meningismus (symptoms similar to meningitis but not caused by)
cerebellar and cranial nerve signs
Cushing’s triad indicate increased intracranial pressure (high systolic BP/decreased respiration/decreased puslse)
What are the usual cause of a subdural haematoma?
acute venous haemorrhage of the cortical bridging veins draining cortical blood into the superior sagittal sinus
What are the symptoms of a subdural haematoma?
decreased levels of consciousness
ipsilateral pupillary dilation
headache
contralateral hemiparesis (paralysis opposite site of body)
What is a transient ischemic attack (TIA)?
What is the most common cause?
a temporary interruption of focal brain circulation that results in a neurologic deficit lasting less than 24 hours (usually only 15 minutes to 1 hour)
common cause embolic disease from heart, carotid or cerebral vessels leading to the temporary blockage
What are the common deficits of a TIA?
Hemiparesis (paralysis of one side of body)
Aphasia (inability to understand or produce speech)
Hemisensory loss
Ataxia (full loss of control of body movements)
Vertigo
Hemianopia (blindness in half optic field)
Confusion
What is a stroke?
What are the two types?
a localised brain injury caused by a vascular episode that last more than 24 hours
2 types:
- Ischaemic - (70-80%) infarction, thrombotic or embolic. resulting from atherosclerosis (usually carotid a.) or underlying heart disease
- Haemorrhagic - when a cerebral vessel weakens and ruptures causing an intracranial bleed affecting a larger brain area
What is a carotid-cavernous sinus fistula?
Is is more common in men or women?
What are the symptoms?
high-pressure (arterial) low-flow lesions often resulting from trauma
more common in men
characterised by: orbital bruit (increased blood flow through collateral arterial supply and intracranial arterial system); exophthalmos (abnormal protrusion of eyeball); chemosis (oedema of the conjunctiva); and extraocular muscle palsy involving CN III, IV and VI
What is vascular (multiinfarct) dementia?
What are common dementia symptoms?
What causes vascular dementia?
What are associated conditions that can lead to multiinfarct dementia?
dementia is an acquired neurologic syndrome presenting with multiple cognitive deficits
includes short-term memory impairment, behavioural disturbances, and/or difficulties with daily functioning
vascular dementias are caused by anoxic damage (lack of oxygen) from small infarcts - accounting for 15-20% of dementia cases
multiinfarct dementia associated with heart disease, diabetes mellitus, hypertension and inflammatory diseases
What is the most common cause of subarachnoid haemorrhage?
rupture of a SACCULAR (localised swelling of a vessel wall) or BERRY (most common/looks like berry on a stem/often appear where vessels branch) ANEURYSM of an artery of circle of Willis
Why is the venous drainage system of the cranial vault so important?
very little space to accommodate large quantities of blood and so needs an efficient system to allow blood to leave the restricted compartment.
What are the 7 paired and 5 unpaired dural sinuses?
paired - 1. transverse, 2. cavernous, 3. greater petrosal, 4. lesser petrosal, 5. sphenoparietal, 6. sigmoid, 7. basilar
unpaired - 1. superior sagittal, 2. inferior sagittal, 3. straight, 4. occipital, 5. intercavernous
Describe the location of the superior sagittal sinus
resides in the superior border of the falx cerebri and runs between the foramen caecum and internal occipital protuberance
Describe the location of the inferior sagittal sinus
midline sinus residing in the free border of the falx cerebri, dorsal to the corpus callosum
joined by the great cerebral vein (of Galen)
Describe the location of the straight sinus
a midline structure that lies within the posterior end of the falx cerebri and in the middle of the tentorium cerebelli
terminates at level of the internal occipital protuberance
formed by the inferior sagittal sinus and great cerebral vein
Describe the location of the sphenoparietal sinus
located along the free (posterior) edge of the lesser wing of the sphenoid bone of the skull
Describe the location of the cavernous sinus
What venous structures/sinuses does it connect to?
situated between dural layers on either side of the sella turcica of the sphenoid bone of the skull
connects to the superior ophthalmic veins, pterygoid plexus of veins, sphenoparietal sinuses, petrosal sinuses and basilar sinus
note - also called Parasellar sinuses
Describe the location of the superior (greater) petrosal sinus
runs along the petrous part of the temporal bone in the base of the tentorium cerebelli, crossing over the trunk of the trigeminal nerve (before it enters Meckel’s cave) and terminates in the sigmoid sinus
Describe the location of the inferior (lesser) petrosal sinus
exits the cavernous sinus and terminates in the sigmoid sinus inferior to the fibres of the facial (CNVII) and vestibulocochlear (CNVIII) nerves
Describe the location of the occipital sinus
lies within the fixed part of the falx cerebelli, running from the foramen magnum towards the internal occipital protuberance to the confluence of sinuses
Describe the location of the transverse sinus
travels in the base of the tentorium cerebelli, along the occipital bone, terminating at the confluence of sinuses
Describe the location of the sigmoid sinus
continuation of the transverse sinus, courses along the posterior cranial fossa, passing inferomedially in an S-shaped pathway to the jugular foramen (becoming the internal jugular vein) via the jugular bulb
What is the confluence of sinuses?
point where the superior and inferior sagittal sinuses, straight and occipital sinuses all meet at the level of the internal occipital protuberance
Describe the location of the basilar sinus
network of venous channels on the basilar part of the occipital bone
has connections to the petrosal sinuses and drains into the vertebral venous plex
What are Emissary veins?
small veins that connect the dural sinuses with the diploic veins in the bony skull, which are connected to the scalp veins
What is meningitis?
What causes it?
What are the symptoms?
How is it diagnosed?
inflammation of the meninges - in particular the arachnoid and pia mater
bacterial or aseptic causes
aseptic includes: viral, drug reactions, systemic diseases
headache, fever, seizures, painful stiff neck
lumbar puncture and examining the CSF
