Week 1 Dry Flashcards
Describe the circle of willis?
Basilar artery formed from vertebral arteries.
It connects to the ICAs via the post. communicating artery.
Post cerebral comes off basilar/post communicating
Middle cerebral comes off ICA
Ant cerebral comes off ICA and are joined to eachother by ant communicating
What arteryies come off the vertebral and basilar arteries?
Post inf cerebellar and Ant spinal arteries come off the vertebral arteries
Ant Inf, Labyrinthine and sup cerebellar come off the basilar (in that order)
Where do the vertebral arteries arise?
Subclavians
Which part of the brainstem is the basilar artery most close to?
Pons
Which surface of the brain is supplied by which cerebral arteru?
Ant - Superior/medial, runs in the longitudinal fissure
Middle - Most of Lateral, runs in the sylvian fissure
Posterior - Posterior, runs in calcarine fissure
What cerebral artery supplies Primary motor cortex?
Ant and middle
What cerebral artery supplies Primary sensory cortex?
Ant & Middle
What cerebral artery supplies Primary Visual Cortex?
Post
What cerebral artery supplies Primary Auditory Cortex?
Middle
What cerebral artery supplies the area of olfaction?
Middle
Which cranial nerve & major Art are closely related to the sup cerebellar artery and how?
Why is this relevant clinically?
Oculomotor & Post Cerebral artery both run just above the Superior Cerebellar Art.
Aneurysms are common here causing III nerve palsy
What pieces of nervous tissue are involved in controlling blood supply to the brain?
Carotid Sinus - Detects pressure in ICA
Carotid Body - Detects Anoxia in ICA
Sympathetic motor nerves also form a plexus around the ICA
What nerves do the Carotid sinus and body connect to?
Both have sensory fibres in the glossopharyngeal nerve
Carotid sinus also uses Vagus
Where do intracranial veins drain to?
Dural venous sinuses between the periocranium and cranial dura
List the important Dural venous sinuses?
Opthalmic Veins -> Cavernous sinus -> IJV
Sup/Inf Petrosal Sinuses -> IJV
Also Inf sagittal -> Straight sinus (joins with Sup sagittal) -> Confluence of sinuses -> Transverse sinus -> Sigmoid sinus -> IJV
What are the important connection between veins outside and inside the cranium, and why?
# Sup Opthalmic Vein is continuous with the facial vein outside and cavernous sinus inside. # Emissary veins are continuous with dural sinuses -> Diploe of bone -> veins of scalp # Inf Petrosal Sinus are connected left-right by the basilar sinus
All of these are potential routes of intracranial infection
What is the 2 most important grooves in the skull base due to arteries?
Carotid groove one either side of the sella turcica
Groove for middle meningeal artery just lateral to foramen spinosum
What drains into the cavernous sinus?
- Opthalmic Veins
- Superficial and middle cerebral veins
- Sphenoparietal veins
What neurovascular structures pass through the cavernous sinus?
- ICA
- Cr Nerves III, IV, V2, V3 & 6
- Cr Nerve II passes just behind the cavernous sinus medially
How does Cavernous Sinus Thrombosis occur and what does it cause?
CST results from infection spreading from the nose, sinuses, ears or teeth.
The sinus thromboses causing oedema & blood to back up
So your eyes bulge and you get cranial nerve palsies of II, III, IV, V2/3 & VI
Explain the blood supply of the Spinal Cord??
You have 1 anterior and 2 posterior spinal arteries which give of multiple segmental spinal arteries
What arteries form the anterior spinal artery?
The two vertebral arteries give off branches which become the Ant Spinal Art, just before they form basilar artery.
What arteries form the posterior spinal arteries?
Branches of the post inf cerebellar art
Explain the venous drainage of the spinal cord?
Ant & Post spinal veins drain into the Internal vertebral (epidural) venous plexus.
In turn the Internal Vertebral Venous Plexus communicates with its external counterpart outside the vertebral canal.
Then it reaches up into the cranium and drains into the intracranial venous sinsues
What are the important Dural folds?
Falx Cerebri
Tentorium Cerebelli
Falx Cerebelli
Diaphragma Selli
What does the falx cerebri attach to?
Anteriorly — Crista Galli & Frontal Crest
Posteriorly — Tentorium Cerebelli
What dural sinuses run within and along the falx cerebri?
Inf Saggital Sinus runs within the upper border of the falx cerebri
Sup Sagittal Sinus runs along the upper border of the falx cerebri
Where does the tentorium cerebelli attach?
Ant/Post Clinoid processes of the sphenoid bones
How does the straight sinus relate to the dural folds?
IT runs along where the falx cerebri joins the tentorium cerebelli
Where does the middle meningeal artery come from?
The maxillary Art through the foramen spinosum
What embryological structures are the ventricles formed from?
Neural Tube Vesicles
What are the parts of the lateral ventricle and in what part of the brain does each lie in?
Anterior Horn - Frontal Lobe
Body - Parietal Lobe
Posterior Horn - Occipital Lobe
Inferior horn - Temporal Lobe
What parts of the brain are the other ventricles (not lateral) found in?
Interventricular Foramen - Temporal
3rd Ventricle - Diencephalon
Cerebral Aqueduct - Midbrain
4th Ventricle - Between Brainstem and cerebellum
What produces CSF?
Choroid plexus which is found within the ventricles
How does CSF reach the subarachnoid space from the 4th ventricle?
Through the two lateral apertures or 1 midline aperture
How is CSF reabsorbed into venous sinuses?
Through arachnoid villi
What are the indentations in the skull cap around the sup sagitall sinus groove?
Indentations of the arachnoid villi in the developing skull
