neuroanatomy I and II Flashcards
layers of the scalp
Skin
Connective tissue
Apoenurosis
Loose connective tissue
Periosteum
what is the proper scalp
skin
connective tissue
aponeurosis
(are connected and move together)
aponeurosis
helps prevent stretching of the scalp
deep scalp
loose connective tissue
periosteum
what is within the loose CT
emissary vein and others
what could travel through the emissary vein
potential infection into the cranial vault
what are meninges
3 layers of tissue to provide protection and support to the CNS (brain and spinal cord)
superfifcal to deep of the meninges
- dura mater
- arachnoid mater
- pia mater
dura mater
- think layer of meninges deep to the calvarium (skull cap)
- encloses dural venous sinuses (major structures that drain the cranial vault)
- at the edge of the skull, at the foramen magnum
- continues around the edge of skull and around the spinal cord
what does the dura mater form
three invagination (folds) with the cranial vault
- falx cerebri
- tentorium cerebelli
- falx cerebelli
where does falx cerebri attach
anteriorly to the crista Galli of the ethmoid bone
layers within the dura mater
2
periosteal layer (superifical) (around the edge of the skull)
meningeal layer (deeper) (around the spinal cord)
- these layers split to help form the dural venous sinuses
spaces within the dura mater
2
- epidural space
- subdural space
why are the spaces within the dura mater potential space?
they are not found unless trauma/disease cause seperation of these layers
arachnoid mater
sits deep to the dura, on the dura
subarachnoid space
between arachnoid and pia, contains cerebrospinal fluid (CSF)
cerebrospinal fluid
- CSF helps metabolically and physically support the brain
- metabollicaly: exchange medium
- physically: buoyancy and cushion
arachnoid granulations
drain CSF through the dura
arachnoid trabeculae
support the arachnoid mater
pia mater
closely covers cortical sulci and gyri
- subpial space exists between pia and cortex (another potential space)
spinal meninges
3 layers of tissue to provide protection and support to the spina cord:
- dura mater
- arachnoid mater
- pia mater
spinal meninges: dura and arachnoid
cover the spinal nerve roots
spinal meninges: pia and dura
denticulate ligaments (from pia) connect to dura for cord stability
spinal meinings: epidural space
contains fat and venous plexuses
subarachnoid space
contain CSF
subdural and subpial space
are potential spaces
what are the ventricles?
4 cavities within the brain responsible for deep CSF flow
- 2 lateral ventricles
- third ventricle
- fourth ventricle
lateral ventricles
- associated with various lobes of the cerebrum (the telencephalon)
- anterior horn
- inferior horn
- posterior horn
- body
- atrium
- interventricular foramen
what does the interventricular foramen (of munro) help with
CSF flow
third ventricle
associated with the thalamus and hypothalamus
(the diencephalon)
- roof
- anterior wall
- 2 lateral walls
- floor
- posterior wall
- interthalamic adhesion (bond of tissue)
cerebral aqueduct
connects the third and fourth ventricles, passing through the midbrain into the pons
fourth ventricle
associated with the pons (the myelencephalon)
- there are 3 apertures in the fourth ventricle (2 lateral and 1 median)
- last part before the spinal cord
- foramina of luschka/lateral apertures
- foramen of magen median aperture
central canal
continues all the way down the spinal cord
- provides metabolic support to the deep spinal cord
choroid plexus
collection of ependymal cell found on the walls of all 4 ventricles, in specific areas
what does the choroid plexus produce
cerebrospinal fluid, which flows into the ventricles
ventricular flow
lateral ventricle–>interventricular foramen–>third ventricle–> cerebral aqueduct–>fourth ventricle
what are the 3 options CSF could go from fourth ventricle
- foramina of luschka
- central canal
- foramen of magendie
CSF exiting the ventricles
- CSF exits into small subarachnoid spaces called cisterns (small cavities)
- from cisterns, CSF flows along the outer cortices of the cerebrum and cerebellum
arachnoid granulations
- CSF exits the subarachnoid space through arachnoid granulations
- these pierce through the dura to drain CSF into the dural venous sinuses
overview of cranial CSF flow
- choroid plexus
- lateral ventricle
- interventricular foramen
- third ventricle
- cerebral aqueduct
- fourth ventricle
- median/lateral apertures
- subarachnoid cisterns
- bathes superficial brain
- arachnoid granulations
- dural venous sinuses
three major branches off the aorta
- brachiocephalic trunk
- left common carotid artery
- left subclavian artery
brachiocephalic truck
ends and splits into the right common carotid artery and the right subclavian artery
four major arteries to the brain
common carotid artery–> internal carotid artery
subclavian artery–> vertebral artery
what canal does the internal carotid artery go through
- carotid canal
what canal does the vertebral artery go through
anterior portion of foramen magnum (anterior to spinal cord)
how is the basilar artery formed
formed by left and right vertebral arteries joining
where does the basilar artery sit
in basilar groove of pons
what does the basilar artery give off
pontine arteries to supply the pons
bifurcation of basilar artery
into 2 posterior cerebral arteries
(supply the posterior cerebral cortex)
circle of wills
anastomosis of arteries providing major cerebral blood supply
contents of circle of willis
- basilar artery
- posterior cerebral arteries
- posterior communicating arteries
- internal carotid arteries
- middle cerebral arteries
- anterior cerebral arteries
- anterior communicating artery
what is the point of the circle of willis
allows blood to get everywhere even if there is some damage (ex. blood clot)
basilar artery bifurcates into?
posterior cerebral arteries
internal carotid artery gives off?
anterior and middle cerebral arteries and posterior communicating arteries
posterior communicating artery
connects internal carotid artery with posterior cerebral artery
- provides connections
how are anterior cerebral arteries connected
by anterior communicating artery
venous drainage
- consists of dural venous sinuses that drain the inner structure of the cranial vault
superior sagittal sinus
- lies along mid-sagittal plane, in falx cerebri
confluence of sinuses
superior sagittal sinus–> confluence of sinuses–> transverse sinuses
- it is the meeting point of all of these sinuses
where does the transverse sinuses sit?
in the tentorium cerebelli
terminal drainage of brain
- transverse sinus becomes sigmoid sinus when exiting tentorium cerebelli
- sigmoid sinus drains into the internal jugular vein
- jugular blub is a superior enlargement of the internal jugular vein
cavernous sinus
venous plexus sitting lateral to the body of the sphenoid bone
- drains eye, parts of cerebral cortex, and pituitary gland
- only one that is pierced (by the internal carotid artery)
- internal carotid artery then curves up to exit the dura, and contribute to the circle of wills
parts of diencephalon
- epithalamus
- thalamus
- hypothalamus
(superior to the midterm)
thalamus
- smell
- automatic actions
- transmitting info
- 80% dicephalon
- interthalamic adhesion
- third ventricle
- internal capsule (bond of white matter)-relays info
hypothalamus
- small
- body activities (homeostasis)
- regulation eating
- body temp
- infundibulum
- pituitary gland
epithalamus
- habenular nuclei
- pineal gland
habenular nuclei
- smell + emotion response to smell
pineal gland
- around 3 vent
- endocrine/secrets melatonin
brainstem
consists of:
- midbrain
- pons
- medulla oblongata
medulla oblongata
- continuation of the superior part of the spinal cord
- form the inferior part of the brainstem
- contains all sensory (ascending) and motor (descending) tracts that connect the spinal cord to the brain
what does the anterior aspect of the medulla have
two prominent bulges called pyramids:
- 90% of axons cross to opposite side
- crossing is called the decussation of pyramids - allows for contralateral control
pons
- superior to medulla, anterior to cerebellum
- contains a control center for respiration
- bridge like, connects sides of the brain
midbrain
- extends upward from pons to diencephalon
- involved in the auditory and visual pathway
what features are on the midbrain
- superior colliculi (visual)
- inferior colliculi (auditory)
protective structure of spinal cord
- vertebral column
- spinal meninges
- cerebrospinal fluid (CSF)
spinal meninges
- pia mater
- arachnoid mater
- dura mater
spinal meninges: epidural space
between vertebral canal and dura
- cushion and CT
spinal meninges: subdural space
between dura and arachnoid
- interstitial fluid
spinal meninges: subarachnoid space
between arachnoid and pia
- shock absorbing bc of CSF
spinal meninges: denticulate ligament
suspend spinal cord in Dural sheath
- trigangle shape
- thickening of pia mater
- protects lateral
spinal cord enlargements
cervical enlargement
lumbosacral enlargement
cervical enlargement
fourth cervical to first thoracic vertebrae (C4-T1)
- supplies the upper extremities
lumbosacral enlargement
- (T9-T12)
- supplies the lower extremities
spinal cord external anatomy
- conus medullaris
- filum terminale
- cauda equina
conus medullaris
- termination of the spinal cord
- located between the first and second lumbar vertebrae (L1-L2)
filum terminale
- extension of the pia mater
- attaches the spinal cord to the coccyx
cauda equina
- lumbar, sacral and coccygeal spinal nerves
- “horses tail”
grey matter of spinal cord
posterior horn- motor actions
lateral horn- smooth muscle, autonomic
anterior horn- contraction of skeletal muscle, sensor
white matter of spinal cord
posterior funiculus
lateral funiculus
anterior funiculus
ascending
sensory
descending
motor
