Activities Flashcards
Identify the le ft and right cerebral hemispheres. What is the name of the fissure that separates them?
Longitudinal fissure
Identify the central sulcus. Which two lobes does it separate?
Frontal and parietal
Find the precentral gyrus (the gyrus that is anterior to the central sulcus) - what lobe does it lie in? It is important for motor function and has a specific name - what is it called?
Frontal lobe
Primary motor cortex
Find the postcentral gyrus (the gyrus that is posterior to the central sulcus) - what lobe does it lie in? It is important for sensory processing and also has a specific name - what is it called?
Parietal lobe
Primary somatosensory cortex
Identify the lateral sulcus. Which lobes does it separate?
Temporal lobe from frontal and parietal
Why is the cerebral cortex referred to as grey matter? What is the cerebral cortex composed of?
It appears grey
Cell bodies and dendrites
What are the 3 meningeal layers called and what order are they in from superficial to deep?
Dura mater
Arachnoid mater
Pia mater
How many layers does the dura have?
2
Outer endosteal
Inner meningeal
What is the falx cerebri and what is its function?
A folding of the meningeal layer of the dura
Separates the 2 cerebral hemispheres
What does the arachnoid mater look like? What fluid lies deep to the arachnoid?
Spider webs
Cerebral spinal fluid
Function of arachnoid granulations
Reabsorption of CSF
What important structure does the pia contribute to?
physically separate the neural tissue from the blood vessels in the subarachnoid space
Which dural fold separates the le ft and right cerebral hemispheres?
Falx cerebri
What parts of the brain are separated by the tentorium cerebelli?
Occipital lobe and cerebellum
Where does blood collect in the following types of intracranial bleeds?
○ Extradural haemorrhage.
Between skull and dura
Where does blood collect in the following types of intracranial bleeds?
○ Subdural haemorrhage.
Between dura and arachnoid
Where does blood collect in the following types of intracranial bleeds?
○ Subarachnoid haemorrhage.
Between arachnoid and pia
Where does blood collect in the following types of intracranial bleeds?
○ Intracerebral haemorrhage.
Within brain below pia
Which type of haemorrhage most commonly forms a convex shape on axial CT images?
Extradural
Which type of haemorrhage most commonly forms a concave shape on axial CT images?
Subdue all
What symptoms or signs might a patient present with if they have an intracranial haemorrhage?
Impairment of functions of the brain due to an increase in intracranial pressure
Consciousness for a ‘lucid’ period before becoming comatose
Death
The major arteries of the cerebral arterial circle anastomose via communicating arteries. Whatʼs the advantage of this anastomotic arrangement?
Allows blood supply to be maintained to areas of the brain even when one of the vessels is occluded
Where do the following arteries arise from?
○ internal carotid arteries.
Common carotid artery
Where do the following arteries arise from?
○ vertebral arteries.
Subclavian arteries
Where do the carotid arteries emerge inside the skull?
Via the Foramen lacerum into the middle cranial fossa
Which areas of the brain are supplied by the:
● Anterior cerebral arteries.
Medial aspects of frontal and parietal lobes
Strip on cortex on superior aspect of brain- motor and somatosensory cortex of lower limbs
Anterior structures of diencephalon
Which areas of the brain are supplied by the:
● Middle cerebral arteries.
Majority of lateral aspects and deep parts of hemispheres- motor and somatosensory cortex of upper limbs, face and trunk
Internal capsule
Some diencephalon structures
Which areas of the brain are supplied by the:
● Posterior cerebral arteries.
Occipital lobe
Inferior temporal lobe
Which layer of the meninges contributes to the formation of dural venous sinuses?
Dura
Into which veins do the dural venous sinuses drain into to reach the heart?
Sigmoid sinuses —> internal jugular vein
Emissary veins (drain venous blood into bones of skull)
What symptoms and signs might a patient present with if they have an occlusion in their dural venous sinuses?
Headache
Compression of intracranial structures
Where is most CSF produced?
Choroid plexus in lateral ventricles
Between which meningeal layers does the CSF flow?
Dura and arachnoid
How does CSF reach the spinal canal?
Central canal
Where is CSF reabsorbed?
Arachnoid granulations
What is the function of CSF?
Physical protection
Mechanism for transfer of certain substances into and out of brain tissue
How can we acquire a sample of CSF from a patient?
○ What layers of tissue do we need to pass a needle through to reach it?
○ What diseases can clinicians test for using CSF?
Spinal tap
- level of L4/L5
- skin, subcutaneous fat, supraspinous ligament, interspinous ligament, Ligamentum flavum, dura, arachnoid
- infection, cancer, encephalitis, high blood glucose
What is hydrocephalus? Can you think of a cause of hydrocephalus, and what would happen if it is not treated?
Accumulation of CSF, characterised by enlarged lateral ventricles
-blockage to flow of CSF through ventricular system eg due to cancer
-causes headaches, vomiting, drowsiness, reduced conscious levels of seizures
Which bones make up the anterior cranial fossa?
Orbital part of Frontal bone
Lesser wings of Sphenoid bone
Cribriform plate and crista galli of the Ethmoid bone
Identify the cribriform plate.
○ Which bone is this structure part of?
Ethmoid bine
● Identify the cribriform plate.
○ What is the name of the linear projection in the middle of it?
Crista galli
● Identify the cribriform plate.
○ Which cranial nerve fibres pass through the holes in the cribriform plate?
Olfactory nerve fibres
On some skulls, you may be able to identify one of the pairs of facial sinuses at the front of the anterior cranial fossa. Which sinuses are these?
Frontal
Maxillary
Sphenoid
Ethmoid
Which bones make up the middle cranial fossa?
Petrous and squamous part of the Temporal bone
Greater wing and body of the Sphenoid bone
Identify the temporal bone.
○ What are the two parts of the temporal bone? What do their names mean?
Petrous part- ‘rock-like’ hard and bulbous inferior and middle part
Squamous part- ‘scale-like’ flare, lateral part
Identify the sphenoid bone.
○ What is the name of the depression in its centre where the pituitary gland is located?
Sella turcica (pituitary fossa)
Name which structure passes through them:
○ Optic canal
Optic nerve
Name which structure passes through them:
○ Superior orbital fissure
Oculomotor nerve
Trochlear nerve
Ophthalmic branch of trigeminal nerve
Abducens nerve
Name which structure passes through them:
○ Foramen rotundum
■ Which parts of the face does this nerve provide sensation to?
Maxillary branch of trigeminal nerve
Middle 1/3 of face including internal nasal cavity, upper teeth, palate
Name which structure passes through them:
○ Foramen ovale
■ What kind of sensation does this nerve provide to the anterior 2/3 of the tongue?
Mandibular branch of trigeminal nerve
General sensation
Name which structure passes through them:
○ Foramen lacerum
Internal carotid artery
Name which structure passes through them:
○ Foramen spinosum - if you look carefully, on some skulls you can see a slight groove in the bone that passes laterally and superiorly from this foramen.
■ Which blood vessel causes this groove?
■ Which kind of intracranial haemorrhage is this structure o en
implicated in?
Middle meningeal artery
Extradural haemorrhage
Which bones make up the pterion?
Frontal bone
Sphenoid bone
Temporal bone
Parietal bone
Which artery is located immediately behind the pterion?
Middle meningeal artery
Which bones make up the posterior cranial fossa?
Occipital bone
Part of the petrous part of the temporal bone
Identify the petrous part of the temporal bone.
○ What is located inside this part of the temporal bone?
The inner ear
Which foramen allows cranial nerves to enter the inner ear?
■ Which nerves travel through it?
Internal auditory meatus
-vestibulocochlear nerve and facial nerves
Identify the jugular foramen.
○ Which large blood vessel passes through it?
■ Which venous structure becomes this vein as it passes through?
Internal jugular vein
-sigmoid sinus
Identify the jugular foramen.
○ Which nerves pass through it?
Glossopharyngeal
Vagus
Accessory
Identify the large foramen in the centre of the posterior cranial fossa.
○ What is its name?
○ What passes through it?
Foramen magnum
- spinal cord
Which bones make up the orbits?
Larger:
Frontal bone
Maxillary bone
Sphenoid
Zygomatic
Smaller:
Ethmoid
Lacrimal
The orbital floor is o ften noted to be the weakest wall of the orbit. Which cavity is located immediately below it?
Sphenoid-ethmoid sinus —> nasal cavity
What are the names of the foramina at the back of the orbit?
○ What do they transmit?
Superior orbital fissure = oculomotor, trochlear, ophthalmic and abducens nerve
Optic canal = optic nerve
Inferior orbital fissure
The lacrimal gland is located in the superior and lateral part of the orbit.
○ Which nerve controls release of tears from the lacrimal gland?
■ Is this a somatic, sympathetic or parasympathetic function?
Facial nerve- parasympathetic
Where do tears drain after lubricating the surface of the eye?
Nasolacrimal duct into nasal cavity
How many extraocular muscles are there?
7
Which one is supplied by the trochlear nerve (CN IV)?
Superior oblique
Which one is supplied by the abducens nerve (CN VI)?
Lateral rectus