CNS anatomy Flashcards
What are the main sutures present on the calvaria?
coronal suture
saggital suture
lambdoid suture
squamosal suture
What is the calvaria?
cranial vault
Which bones articulate at the coronal suture?
parietal and frontal bones
Which bones articulate at the saggital suture?
2x parietal bones
Which bones articulate at the lambdoid suture?
2x parietal and occipital bones
Which bones articulate at the squamosal suture?
temporal squama and parietal bone (lower border)
What suture is present between the 2 halves of the frontal bone in the foetal skull? By what age does this suture close?
frontal suture
6-8 years of age
What is the significance of the anterior and posterior fontanelles?
Allow child’s head to pass through the birth canal
As bony skull plates can flex due to the space in the fontanelle
What are the attachment points for the dura to the base of the cranial cavity?
anterior and posterior clinoid processes
Where does the skull articulate with the first cervical vertebra?
at the foramen magnum and occipital condyles
The internal carotid artery has a tortuous course through a canal - which is this?
carotid canal
and foramen lacerum
What is the jugular foramen?
point at which venous blood drains from the brain via the internal jugular vein
What are the main lobes of the brain?
parietal
frontal
occipital temporal
cerebellum
What are the main features present on the brain surface that delineate the main lobes?
longitudinal fissure transverse fissure lateral (Sylvian) fissure central sulcus parieto-occipital sulcus
Where is the precentral and postcentral gyri located? What structure is located in these locations?
anterior and posterior to the central sulcus respectively
primary motor cortex (anterior to central sulcus)
somatosensory cortex (posterior to central sulcus)
Which is the only structure on brain surface that runs uninterrupted from the longitudinal fissure to the lateral sulcus?
central sulcus
What is the corpus callosum?
massive bundle of commissural fibres
connects left and right side of cortex halves
What structures lie inferior to the corpus callosum?
fornix septum pellucidum (suspended between fornix and underside of corpus callosum)
What structure follows the curve of the corpus callosum?
cingulate gyrus
superior to this is the cingulate sulcus
Where does the cingulate sulcus terminate?
by passing upwards towards a sulcus
then continues over the surface of the parietal lobe
sulcus immediately anterior to this is the central sulcus
What are the 3 layers of meninges that cover the CNS?
Pia mater
arachnoid mater
dura mater
What is the nature of the pia mater?
very fine and is adherent to the brain surface
What ia the nature of the arachnoid mater?
lies between pia mater and dura
Blood vessels that supply the brain run through the subarachnoid space
What is the nature of the dura mater?
tough and fibrous and is largely adherent to the inside of the skull
What is the diaphragma sellae?
flat piece of dura mater with a circular hole
allowing vertical passage of pituitary stalk
Which structure lies beneath the diaphragma sella?
pituitary gland = hypophysis
What is the fossa hypophyses?
most inferior pair of the sella turcica
Through which structure is venous blood from the brain returned to systemic circulation?
venous sinuses
= series of valveless channels through the dura
Which sinuses converge at the CONFLUENCE SINUSORUM?
- superior sagittal sinus
- straight sinus
- occipital sinus
Where does blood drain beyond the confluence sinusorum?
left and right transverse sinuses
What are the different sinuses that are present within the venous sinuses?
- superior sagittal
- inferior sagittal
- straight
- petrosal
- transverse
- sigmoid
Where do the sigmoid sinuses terminate?
jugular foramen
Where is CSF continuously produced?
in choroid plexus mainly within lateral ventricles
= invagination of blood capillaries into the ventricles
What course does the CSF take (circulation)?
(lateral ventricle): through the intraventricular foramen into the third ventricle
then via cerebral aqueduct into fourth ventricle
then out via foramen of Magendie and foramina of Luschka
into cisterna Magna and subarachnoid space
Where are the arachnoid granulations located? What is the function of these structures?
either side of the longitudinal fissure
Role: contains vilii. important in returning CSF to the venous circulation
Where does the brain receive its blood from?
- vertebral arteries
- internal carotid arteries
What are the differences in the origins of the left and right common carotid arteries?
LEFT: originates at the aortic arch
RIGHT: originates from brachiocephalic trunk
At what vertebral level does the common carotid bifurcate? Which vessels are formed from this?
C4
at upper border of thyroid cartilage
forms internal and external carotid arteries
Which branch of the common carotid artery gives no branches to the neck or head?
internal carotid
What is the first branch of the subclavian arteries?
vertebral arteries
What is the route of the vertebral arteries?
through the foramina transversaria
round the occipital condyles
into the cranial cavity via the foramen magnum
What do the left and right vertebral arteries unite to form?
Basilar artery
ascends the slope (= clivus) to the cranial base
The circle of Willis is comprised of which main arteries?
basilar and internal carotids = ring of arteries
Which arteries are comprised within the circle of Willis?
- posterior cerebral
- posterior communicating
- middle cerebral
- anterior cerebral
- anterior communicating
Where does the internal jugular vein terminate?
Joins with subclavian vein to become brachiocephalic vein (innominate vein)
Which structure allows CSF to flow from the fourth ventricle into the cisterna magna?
foramen of Magendie (Median aperture)
What connects the two lateral ventricles to the third ventricle allowing CSF flow between?
intraventricular foramina
Wha is the foramen of Magendie
a subarachnoid cisterna located between the cerebellum and medulla
From here, CSF flows through the subarachnoid space
What are the foramina of Luschka?
= 2x lateral apertures
drain CSF into the cerebellopontine angle cistern, which lies between the pons and cerebellum
CSF can flow through the subarachnoid space from here
What nerves are contained within the cerebellopontine angle?
facial nerve
vestibulocochlear angle
What is dysdiadochokinesis?
inability to perform rapid alternating movements on the same side
suggests lesion in cerebellum on same side
Where does the spinal cord terminate in neonates?
L3
Where does the spinal cord terminate in adults?
L1-2
What are the branches of the external carotid artery/?
“Some Angry Ladies Fight Off PMS”
Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial temporal
What are the cerebral branches of the internal carotid artery?
“Only Press Carotid Arteries Momentarily”
Opthalmic Posterior communicating Choroidal Anterior cerebral Middle cerebral
At what level is the hyoid bone found?
C3
At what level is the notch of the thyroid cartilage?
C4
At what level does the cricoid cartilage terminate?
C6
What structures are found at the lower border of the cricoid cartilage?
- start of trachea
- largo-tracheal jnct
- pharynx-oesophagus jnct
- C6 transverse foramina
- middle cervical sympathetic ganglion
- point at which inferior thyroid enters the thyroid
- superior belly of omohyoid crosses the carotid sheath
