Neuraxial Blocks Flashcards
What vertebral level corresponds with this landmark: Spine of Scapula
T3
What vertebral level corresponds with this landmark: Posterior Superior Iliac Spine
S2
What vertebral level corresponds with this landmark: Superior Aspect of Iliac Crest
L4
What vertebral level corresponds with this landmark: Vertebra Prominens
C7
What vertebral level corresponds with this landmark: Inferior Angle of Scapula
T7
What vertebral level corresponds with this landmark: Rib margin 10cm from the midline
L1
How many vertebrae are there?
33
How many cervical vertebrae?
7
How many thoracic vertebrae?
12
How many lumbar vertebrae?
5
How many sacral vertebrae?
5 -fused
How many coccygeal vertebrae?
4-fused
Another name for facet joint?
Zygapophyseal Joint
What is the intercristal line?
AKA Tuffers Line
A horizontal line drawn across the superior aspects of the iliac crests correlates with the L4 vertebra.
The interspace above the intercristal line correlates with?
L3-L4
The interspace below the intercristal line correlates with?
L4-L5
In infants, up to 1 year, the intercristal line correlates with the?
L5-S1 interspace
What is the Sacral Hiatus
- Coincides with S5
- Covered by sacrococcygeal ligament
- Provides entry point to epidural space, useful in pediatrics
What is the sacral cornua
bony nodules that flank the sacral hiatus
Where is the conus medullaris located in adults and infants?
Adult: L1-L2
Infant: L3
What and Where is the cauda equina?
Bundle of spinal nerves extending from the conus medullaris to the dural sac.
Nerve and Nerve Roots from L2-S5 nerve pairs and coccygeal nerve
Where does the subarachnoid space terminate? What vertebrae?
dural sac
Adult: S2
Infant S3
What anchors the spinal cord to the coccyx?
Filum Terminale
What two points is the Filum Terminale fixed at?
- conus medullaris
- coccyx
Describe the location of the supraspinous ligament
Runs most of the length of the spine and joins the tips of the spinous processes
Describe the location of the Interspinous Ligament
Travels adjacent to and joins the spinous processes
Describe the location of the Ligamentum Flavum
2 Flava run the length of the spinal canal
Form the dorsolateral margins of the epidural space
Where is the ligamentum flavum thickest?
Lumbar region
Piercing the ligamentum flavum contributes to losing resistance when the needle enters the ____?
Epidural Space
Describe the location of the posterior longitudinal ligament?
Travels along the posterior surface of the vertebral bodies
Describe the location of the anterior longitudinal ligament
It attaches to the anterior surface (tummy side) of the vertebral bodies and extends the entire length of the spine.
It also attaches the annulus fibrosus of the intervertebral discs
During the midline approach, the needle [asses through how many and which ligaments?
passes through 3
Supraspinous Ligament
Interspinous Ligament
Ligamentum Flavum
During the paramedian or Taylor approach, how many ligaments does the needle pass, and which ligaments?
1 ligament: Ligamentum Flavum
With either approach, midline or paramedian, the needle should NEVER pass through which ligaments?
Anterior or Posterior Longitudinal Ligaments
When is the paramedian approach useful?
When the interspinous ligament is calcified or when the patient cannot flex their spine
What position can the paramedian approach be performed in?
Sitting, lateral, or prone
The paramedian approach involves inserting the needle:
15 degrees off the midline or
1cm lateral and 1 cm inferior to the interspace
Name the borders of the epidural space: cranial, caudal, anterior, posterior, lateral
Cranial: Foramen Magnum
Caudaul: Sacrococcygeal Ligament
Anterior: Posterior Longitudinal Ligament
Posterior: Ligamentum Flavum, Vertebral Lamina
Lateral: Vertebral Pedicles
Epidural fat acts as a sink for lipophilic drugs, reducing their bioavailability. List these drugs in order of bioavailability in the epidural space: fentanyl, morphine, bupivacaine, lidocaine
Bupivacaine > Lidocaine and Fentanyl > Morphine
The group of epidural veins that drain venous blood from the spinal cord is called?
Batson’s Plexus
What regions do the epidural veins pass through within the epidural space
anterior and lateral regions
Conditions such as obesity and pregnancy increase or decrease the epidural space?
Decrease. Increases in intraabdominal pressure cause engorgement of Batson’s plexus. Associated with an increased risk of needle injury or cannulation during neuraxial techniques.
Inadvertent local anesthetic injection into the subdural space with cause?
If using epidural dosing: A high spinal
If using spinal dosing: A failed spinal
The subarachnoid space lies deep the arachnoid mater. Name a few things it contains:
CSF, Nerve Roots, Rootlets, and the spinal cord
What is the target area when performing a spinal anesthetic?
Subarachnoid Space
