Neuroanatomy, Brain, and Spinal Cord Flashcards
What are the cranial meninges?
Dura mater
Arachnoid mater
Pia mater
Dura mater (tough mother)
tough, thick external fibrous layer
Arachnoid mater (spider mother)
thin intermediate layers
Pia mater (gentle mother)
delicate internal vascular layer
What type of hematoma can occur in the dura mater?
epidural hematoma; on top of the dura
Blood supply to the dura mater
middle meningeal artery
What are the dural reflections?
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Falx cerebri
separates L and R cerebral hemispheres
Sagittal vein - drainage of the brain
Falx cerebelli
separates cerebellar hemispheres
Tentorium cerebelli
separates occipital lobes from cerebellum
Above - posterior
Below - anterior
What are the dural venous sinuses?
Superior sagittal sinus Inferior sagittal sinus Straight sinus Transverse sinuses Sigmoid sinuses Occipital sinus Cavernous sinus
Drains into IJV to Vena Cava
Cavernous sinus
Bilaterally on each side of sella turcica on sphenoid bone
Plexus of veins from orbit to temporal bone (petrous part)
What structures run among the veins?
Internal carotid a.
CNs III-VI
What is outside of the cavernous sinus?
CNV1 and V2
False localizing sign
compression in the cavernous sinus (not the brain stem)
Clinical correlate: Subdural hematoma
hemorrhage beneath the dura
associated with trauma
rotation
slow bleed
Parts of the brain
cerebrum
cerebellum
brainstem
Cerebum components
Frontal, Parietal, Temporal, Occipital
Frontal lobe
voluntary motor functions, planning, mood, smell and social judgment
Parietal lobe
receives and integrates sensory information
Occipital lobe
visual center of brain
Temporal lobe
areas for hearing, smell, learning, memory, emotional behavior
limbic system
Anterior cranial fossa
Frontal lobes
Olfactory bulbs and tract
Middle cranial fossa
Temporal lobes (and pituitary gland)
Brainstem components
Midbrain, pons, and medulla oblongata (respiration and heart rate)
Function of brainstem
Produce rigidly programmed, automatic behaviors necessary for survival (like breathing)
Cerebellum component
Arbor vitae (tree of life)
Cerebellum function
balance, smooth/coordinated motion
takes information from outside world
inhibited by alcohol intake
Posterior cranial fossa
Brainstem
Cerebellum
Grey and white matter
Grey - cell bodies
White - axons
Grey matter
nuclei deep within brain
White matter
forms tracts that connects parts of the brain
Ventricular system
CSF secreted 400-500 mL/day by cells in choroid plexus
Flows into cisterns, then superiorly through sulci and fissures of cerebrum
Ventricular system function
buoyancy of brain
protective cushioning
CSF absorption
Absorbed into venous system via arachnoid granulations
Clinical correlate: hydrocephalus
Overproduction of CSF, flow obstruction, or malabsorption
Excess CSF: dilates ventricles, thins brain
Blood supply to the brain
internal carotid aa.
vertebral aa.
Vertebral aa.
Branch of subclavian a.
Course through transverse foramina of vertebrae
Vertebral aa. forms what?
Vertebral aa. come together to form basilar a. (over the pons)
Circle of Willis
Anterior cerebral a. Middle cerebral a. Posterior cerebral a. Basilar a. Vertebral a.
All blood supply tp the brain
Corpus callossum
Connects both sides of the brain
Functions of the CSF
nutrients
buoyancy
shock absorption
Venous drainage of the brain
Cerebral veins
Great cerebral veins
Cerebral veins
neartest dural venous sinus
Great cerebral vein
midline
merges with inferior sagittal sinus to form the straight sinus
Spinal cord and meginges
Vertebral canal and spinal cord
vertebral canal
spinal cord, meninges, spinal nerve roots
spinal cord
continuation of the medulla oblongata
Ends ~T12-L3
Two enlargements
cervical (gives rise to brachial plexus) and lumbosacral (gives rise to lumbar and sacral plexuses)
What are the spinal meninges?
Dura mater Arachnoid mater Pia mater Epidural space Subarachnoid space
Dura mater
forms dural sac, ends at S2
What is deep to arachnoid mater?
subarachnoid space! cerebrospinal fluid (CSF)
Clinical correlate: lumbar puncture
“spinal tap”
Needle inserted into subarachnoid space to obtain sample of CSF from lumbar cistern
Between L3 and L4
Denticulate ligaments
sheet of pia mater, suspends spinal cord in the dural sac
Conus medullaris and cauda equina
L1-L2
terminal end
cauda equina
Spinal nerves
31 pairs: 8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
Where do rootlets converge?
dorsal and ventral roots
Dorsal roots
afferent (sensory)
Ventral roots
efferent (motor) to skeletal muscle and presynaptic autonomics
What is a spinal nerve?
Dorsal root + Ventral root