Neuraxial Flashcards
of vertebrae and nerves
- 33 vertebrae
- 7 cervical (neck)
- 12 thoracic
- 5 lumbar
- 5 sacral (fused)
- 4 coccygeal (fused)
- 31 spinal nerves
- 8 cervical
- 12 thoracic
- 5 lumbar
- 5 sacral
- 1 coccygeal
supraspinous ligament
- runs from C5 to sacrum
- resids on top of each spinous process, continuous, runs all the way down
- joins the tip of the spinous processes
Interspinous Ligament
- in between each spinous process
ligamentum flavum
- yellow, tough, thick ligament
- thickest in the midline at a L3
- wedge shaped, composed of elastin
- extends from FORAMEN MAGUM to SACRAL HIATUS
- as your pt gets older, the flavum can get weaker and feel less like a landmark
posterior longitudinal ligament
- posterior surface of vertebral bodies, C2-SACRUM
anterior longitudinal ligament
- anterior surface of vertebral bodies C1-SACRUM
vertebral curves
- HIGH (when supine)
- L3, C5
- LOW (when supine)
- S2, T5
dermatomes:
- C6 - tumb
- C7 - index and middle finger
- C8 - 4th and 5th finger
- T1 - elbow
- T4 - nipple line
- T6 - xiphoid
- T8 - last rib
- T10 - umbilicus
- T12 - pubic symphysis
- L4 - anterior knee
CSF volumes
CSF volume
- 150 mL in the subarachnoid space
- CSF replaced 3-4x per day
- made by choroid plexus, rate of 21 mL/hr
CSF SG:
- nicole: 1.004 - 1.008
- Apex:
Anterior Spinal Artery
- arises from joining of vertebral arties
- perfuses the anterior 2/3 of the superior (Short) segment of spinal cord
- runs entire length of spinal cord
Posterior Spinal Arteries
- two!
- run the entire length of the spine
- arise from a branch of either the vertebral arteries or hte psoterior inferior cerebral artery
- supply posterior 1/3 of spinal cord,
- only supplies the short, superior segment
Posterior spinal cord has better continuity of blood supply!
Remained of spinal cord relies on blood supply from
- anterior spinal artery - anterior 2/3 spinal cord, superior, short segment
- 2 posterior spinal arteries, posterior 1/3 of spinal cord, short, superior segment
Remained of spinal cord relies on BRANCHES from cervical, deep cervical, vertebral, posetrior intercostal and lumbar arteries, enter the vertebral column through intervertebral foramina. +Artery of Adamkiewics
Artery of Adamkiewics
- also known as great anterior segmantal medullary artery
- provids circulation to the inferior two thirds of the anterior spinal cord
- generally arises from T9 - T12 on the left side of the aorta
differential blockade in spinals
IN SPINALS
- autonomic blockade is 2-6 dermatomes higher than sensory blockade
- sensory blockade is 2 dermatomes higher than motor block
differential blockade in epidurals
IN EPIDURALS
- No autonomic differential bloackde with epidural anesthesia
- sensory blockade is 2-4 dermatomes HIGHER than motor blockade
CV changes with neuraxial
- decrease in SVR of 15-20%
- decrease in preload of 10-15%
- venous dilation > arterial dilation
- sympathectomy
fluid bolus rec: 15 mL/kg
+ vasopressors
+ anti-cholinergics if necessary
GI/Renal effects with neuraxial
- 20% N/V
- Hyper-peristalsis from sympathectomy and unopposed parasympathetics
- maintenance of MAP guards against untoward effects to liver
- Renal blood flow is autoregulated therefore minimal effects
- urinary retention!
low CBF with neuraxial is manifested by
- N/V
- if sufficently dereased -> apnea and hypoxia
pencil point needle names
- sprotte
- whitacre
- pencan
cutting needle names
- quincke
- pitkin
hyperbaric solution SG
- >1.11
- CSF SG: 1.004 - 1.008
Isobaric SG
~ 1.006
CSF SG: 1.004 - 1.008
Hypobaric SG
<1.005
CSF SG: 1.004 - 1.008
epidural space is widest at
L2
(5 mm)
- ligamentum flavum widest at L3
caudal anesthesia carries high risk of
injection into venous plexus
+ rxn to test dose for epidural
- increase of HR/BP by 15-20% within 1 minute - + for intravascular
- numbness of legs/motor blockade within 1 minute -> intrathecal
Sacral hiatus
- corresponds with S5
- covered by the sacrococcygeal ligament
- provdes entry point to epidural space (in children)
apnea is usually the result of
cerebral hypoperfusion and ischemia to respiratory drive center