Spinal Cord, Brain, Meninges Flashcards
Where is CSF located?
Subarachnoid space (superficial to pia mater and deep to arachnoid mater)
Where is a caudal epidural performed?
sacral hiatus
What is numbed by an epidural block in lumbar region?
dorsal and ventral roots in lumbar region
Where does the dural sac (dura mater) terminate?
S2 vertebral level
What is arachnoid mater deep to?
dura mater
What is the name for the enlargement of subarachnoid space in the lower lumbar region of the vertebral column?
lumbar cistern
Denticulate ligaments are lateral extentions of which spinal meningeal layer?
pia mater
In adults how much of the vertebral canal does the spinal cord occupy?
2/3 since growth of the vertebral column exceeds that of the spinal cord during development
Where are the two spinal cord enlargements?
- Cervical enlargement
- ventral rami give rise to the brachial plexus - Lumbosacral enlargement
- ventral rami give rise to the lumbosacral plexus
Where does the conus medularis terminate?
L1 or L2
-in children the conus medullaris may terminate as low as L3
To performa lumbar puncture (spinal tap) where is the needle inserted?
L3-L4 interlaminar space
or
L4-L5 interlaminar space
What makes up the cauda equina?
elongated lumbosacral (and coccygeal if present) dorsal and ventral roots
Where does the filum terminale start and end?
Start: tip of the conus medullaris
End: passes through the sacral hiatus to attach to the coccyx
Where are ventral and dorsal roots located in relation to the vertebral canal?
within the vertebral canal
Where are dorsal root ganglia located?
dorsal root ganglia are located in intervertebral foramina
What is the name for the roof of the skull?
calvaria
What is the name for the floor of the skull?
basicranium
Name the three principle sutures of the skull?
- Sagittal (between parietal bones)
- Coronal (between frontal and parietal bones)
- Lambdoid (between occipital, temporal, and parietal bones)
Pterion is the junction between which bones?
- parietal
- temporal
- frontal
- sphenoid
Fractures at pterion can injure which vessel?
anterior branch of the middle meningeal artery
-causes an epidural hematoma
Middle meningeal artery supplies what?
cranial dura mater
How many layers does the spinal dura mater have? the cranial?
Spinal:
1 layer
Cranial dura mater: 2 layers (external periosteal layer, internal meningeal layer)
Which cranial nerves innervate the cranial dura mater?
- Trigeminal (CN V)
- Vagus (CN X)
*clinically relevant or headache or migraine
What type of hematoma can occur at the dura-arachnoid junction?
dural border (subdural) hematoma
Arachnoid granulations function
transfer of CSF to the venous system
Name the 4 dural reflections
- Falx cerebri
- Tentorium cerebelli
- Falx cerebelli
- Diaphragm sellae
Where is the anterior attachement of the Falx cerebri
frontal crest and crista galli
Where is the posterior attachment of the Falx cerebri?
occipital bone
Which dural reflection is between the occipital lobes of the cerebrum and cerebellum (transverse)?
Tentorium cerebelli
Where does the diaphragm sellae attach?
clinoid processes
-forms a roof over pituitary gland but allows infundibulum (pituitary stalk) and veins to pass through
Where do dural venous sinuses drain?
internal jugular veins
What two structures combine to form the straight sinus?
- Great cerebral vein
- Inferior sagittal sinus
*at the junction between falx cerebri and tentorium cerebelli
What combine to form the confluence of sinuses?
- superior sagittal sinus
- straight sinus
3 occipital sinus
What path does blood take from the confluence of sinuses to the internal jugular vein?
Confluence of sinuses > transverse sinuses > Sigmoid sinuses > internal jugular
Which two sinuses drain directly into the internal jugular veins?
- Inferior petrosal sinus
2. Sigmoid sinus
What are the three structures that the cavernous sinuses drain into?
- Superior petrosal sinus (joins the transverse)
- Inferior petrosal sinus (joints the internal jugular)
- Pterygoid plexus
Which two structures pass through the cavernous sinus?
- Internal carotid artery
* only structure in the body where an artery passes through vein - Abducent nerve (CN VI)
Which 4 structures are in the lateral walls of the cavernous sinuses?
- Oculomotor (CN III)
- Trochlear (IV)
- Opthalmic (V1)
- Maxillary (V2)
What are the folds in the surface of the brain called?
gyri
What are the grooves in the brain surface?
sulci
What are the 3 components of the brainstem?
- Midbrain
- Pons
- Medulla oblongata
*gives rise to most cranial nerves
Vertebral arteries supply which part of the brain?
posterior circulation
travel within transverse foramina (C6-C1
Where do the vertebral arteries enter the brain?
foramen magnum
Vertebral arteries give rise to what artery?
basilar artery
What are the three branches of the internal carotid?
- Anterior cerebral
- Middle cerebral
- Opthlamic artery (doesn’t supply brain)
*connects via the posterior communicating artery to the posterior cerebral
Where does the internal carotid artery enter the cranium?
carotid canal in temporal bone
then courses medially and horizontally- superior to cartilage covering foramen lacerum
