Neuraxial Blocks Flashcards
3 names for spinal?
spinal, subarachnoid block, SAB
4 names for epidural?
epidural, extradural, caudal, central neuroaxial blockade
How many cervical, thoracic, lumbar, sacral, and coccygeal vertebrae are there and are they anterior or posterior?
cervical: 7 and anterior; thoracic: 12 and posterior; lumbar: 5 and anterior; sacral: 5 and posterior; coccygeal: 4
Which parts of the spine are fused in adults?
sacral and coccygeal
Landmark for T7?
line drawn on the lower borders of the scapula
Landmark for L4 is also known as?
Tuffier’s line
Landmark for S2?
line between posterior superior iliac spines (distal extend of dural sac)
Spinal cord stops at the level of? And what emerges from there?
L1; cauda equina
6 characteristics all vertebrae have?
vertebra body, 2 pedicles (notched for nerve roots), 2 transverse processes (notched for muscle attachment), 2 laminae (one left and one right), 1 spinous process (allows us to tell what level we’re at), 4 articular processes (2 project upward and 2 downward)
What part of the vertebra serves as synovial joints and allow us to bend, twist, and move spinal column?
articular processes
What part of vertebra do we palpate from the outside?
spinous process
These 2 kinds of vertebrae in the spine are more horizontal?
lumbar and cervical
From cephalad to caudad what happens to the vertebral laminae?
they become more vertical
Lumbar spinous processes have what shape characteristic?
they’re shorter and broader
The spinous process angle of cervical, thoracic, and lumbar?
cervical: more horizontal but small; thoracic: angular; lumbar: almost horizontal and bone is very thick
A way to get the sacral region anesthetized?
Have pt lie on side and flat, place small pillow under knees and flatten out lumbar curve which promotes more even distribution of hyperbaric LA in spine
Hyperbaric solution has a viscosity that compares how to the CSF?
hyperbaric solution has > varicity than CSF
What holds together the anterior vertebral bodies?
anterior longitudinal ligament
This ligament is on the far side of the dura and holds together the posterior part of the vertebral bodies?
posterior longitudinal ligament
This ligament joins the vertebral spines?
supraspinous
Where does the supraspinous ligament extend from?
occipital protuberance to coccyx
This ligament runs between the spinous processes?
interspinous
Where does this ligament extend to?
foramen magnum to sacral hiatus
Where does the epidural space extend to?
base of skull to sacrococcygeal membrane
5 things in epidural space?
epidural veins, fat, lymphatics, arteries, nerve roots
Skin to epidural space is how many cm?
2.5-8
In adults the spinal cord extends to what vertebra? In children it extends to where?
L1; L3
What is the tapered end of the spinal cord called?
conus medullaris
What anchors the spinal cord to the coccyx?
filum terminale
What is significant about the cauda equina and an epidural?
the nerve roots in the cauda equina are pushed away from the needle
3 layers of meninges?
dura, arachnoid, pia
Which space contains the CSF?
subarachnoid space
At what level does the anterior spinal artery arise? And from what artery does it arise?
level of foramen magnum; vertebral artery
At what level does the posterior spinal artery arise? And what artery does it arise from?
foramen magnum; posterior inferior cerebellar artery
How many pairs of segmental radicular arteries supply the nerve roots and spinal arteries?
21
This artery supplies the lower thoracic and upper lumbar parts of the cord?
anterior radicular artery of Adamkiewicz/radicularis magna
In the cervical region, spinal arteries receive from from what 2 arteries?
vertebral arteries from posterior inferior cerebellar arteries and segmental branches from cervical radicular artery
In the thorax and lumbar region, spinal arteries receive blood from what arteries?
radicular
The artery of Adamkiewica is also known as?
radicularis magna
The principal arteries for the spinal cord are?
thoracic radicular artery and arterioradiculus magna/major anterior radicular artery
The blood supply of the lower 2/3 of the spinal cord is typically found between what levels?
T11 and L3
CSF is between what 2 layers of spinal cord?
pia mater and arachnoid mater
Where is CSF produced?
ependymal cells in choroid plexus
Where is CSF absorbed?
arachnoid villi
How many mL of CSF is produced per day?
500
Total volume of CSF in body and in spinal cord?
120-150 mL; 25-35 mL in spinal cord
Specific gravity of CSF?
1.004-1.009
Pressure in CSF?
6-8
4 functions of CSF?
immunity, shock absorber, chemical stability prevention of brain ischemia
This supplies the posterior 1/3 of cord?
paired posterior spinal arteries
The single anterior spinal artery arises from?
vertebral artery
The paired posterior spinal arteries arise from?
cerebellar arteries
This artery arises from the aorta?
artery of adamkiewicza
What does artery of adamkiewicz supply?
anterior lower 2/3 of cord
6 blood supply arteries/veins to cord?
single anterior/spinal artery; paired posterior spinal arteries, intercostal and lumbar arteries, artery of adamkiewicz, epidural veins
In the upright position what is the fullness of the epidural veins?
they’re enlarged d/t venous pressure
3 areas on spinal cord that are most vulnerable to deprivation of blood supply?
T1-T3; T5; L1
3 signs from ischemia of anterior central part of cord?
flaccid paralysis, loss of pain and temp sensation
Thrombosis of great radicular artery of Adamkiewicz may cause?
paraplegia
The spinal nerve that comes across the L4 area after you’ve punctured the skin, SQ fat, supraspinous, intraspinous, ligamentum flavum, epidural space, intrathecal space, filum terminale, cauda equina?
ventral and dorsal ramus
Motor fibers are?
A-a
These fibers are responsible for touch and pressure?
A-B
These fibers are responsible for proprioception?
A-y
These fibers are responsible for pain and temp and are lightly myelinated?
A-g
These fibers are preganglionic and autonomic?
B
These fibers are responsible for pain and temp and are not myelinated?
C
Biggest fibers?
A-a