week 4- femoral and ankle Flashcards
If you get a negative aspirate, does that mean you are not within a blood vessel? AKA ball valve phenomenon
No, you could be inside the lumen and sucking the far vessel wall up against the end of the needle, creating negative aspirate but still being within the vessel.
If your patient seizes due to LAST, should you continue with surgery?
NO, monitor patient for 23 hours and create a record.
Femoral nerve block works on __ thigh, __, and the medial aspect __.
anterior thigh
patella
medial aspect below the knee
Can your patient walk after getting a femoral nerve block?
NO, non-weight bearing for the length of LA duration, due to quad weakness.
Reasons to get a femoral nerve block
repair quad tendon, quad muscle biopsy, saphenous vein stripping, femur and knee surgery, femur fractures, total knee replacement arthroplasty.
ABSOLUTE contraindications for femoral nerve block
practitioner inexperience, patient refusal, infection at the site
What is the double crush phenomenon?
when someone has pre-existing peripheral neuropathy and you dump local anesthetic on them that limits blood flow to that nerve
RELATIVE contraindications for femoral nerve block
previous femoral vascular graft, large lymph nodes or tumor, pre-existing femoral neuropathy (double crush)
the femoral nerve is the __ of the lumbar plexus
largest
what spinal nerves make up the lumbar plexus?
T12-L5. Our “Tee” time is at 12, so we’ll be done by 5 at the “Latest”
what spinal nerves does the femoraL nerve originate from?
L 2,3,4
there are 3 vowels in femoral
As the femoral nerve passes into the thigh it divides into the __ and __ branches
anterior and posterior
ABOVE the fascia __ (and below the fascia lata), the anterior branch innervates the __ and __ muscles
fascia iliaca
sartorius and pectineus muscles
BELOW the fascia __, the posterior branch innervates the __ muscle and knee joint and gives off the __ nerve
fascia iliaca
quadriceps muscle
saphenous nerve
the __ nerve supplies the skin of the medial aspect of the leg below the knee and is __ only
saphenous nerve
sensory only
you must pierce BOTH the fascia __ and the fascia __ to provide a femoral nerve block
fascia lata
fascia iliaca
if you accept the sartorius and inject, you just __ your local anesthetic
wasted
if you pierce the fascia iliaca and accept twitches from quads and patella, you just hit
pay dirt
nerve artery vein from lateral to medial
NAV
the only two dermatomes to memorize for the femoral block are the femoral and saphenous
can you point them out on your own leg?
point of injection for a femoral block is down one cm from __ crease and lateral one cm from __ artery
down one cm from inguinal crease
lateral one cm from femoral artery
why inject cephalad with a femoral block?
better opportunity to cover all of the posterior component.
when doing a femoral nerve block, if you don’t get any twitches, what is the problem and solution?
probably too far medial or lateral, relocate femoral artery and reinsert using systematic angulation
when doing a femoral nerve block, if you hit bone, what is the problem and solution?
too deep, withdraw to skin level and reinsert in different direction
when doing a femoral nerve block, if you get a local twitch, what is the problem and solution?
probably directly stimulating illiopsoas or pectineus muscle and too deep, withdraw to skin level and reinsert in different direction
when doing a femoral nerve block, if you get sartorius muscle twitches, what is the problem and solution?
too anterior and medial, redirect laterally and advance 1-3 mm deeper
when doing a femoral nerve block, if you get positive aspirate, what is the problem and solution?
femoral artery puncture, needle too medial, withdraw needle (if hematoma hold pressure 2-3 minutes), then reinsert 1 cm more lateral
when doing a femoral nerve block, if you get patella or quad twitch, what is the problem and solution?
NO PROBLEM, accept and inject, pay dirt
What are some indicators of possible intraneural injection?
severe pain, high pressure to inject
“B” bevel needes have a shorter bevel, thus a greater angle of bevel.
just fyi
what to do with a sartorius twitch
direct more lateral and deeper
in order to be successful at an ankle block, you must block __ nerves, all of which are __
five nerves
sensory, NO motor
What are some indications for ankle block?
any surgery on the foot
what are some contraindications for ankle block?
patient refusal, infection, edema, burns, soft tissue trauma, distorted anatomy, vascular compromise, severe coagulopathy
what are the five nerves involved in ankle block?
saphenous post. tibial sural superficial peroneal deep peroneal
where does the saphenous nerve come from and what spinal nerves specifically?
femoral nerve
L3-4
where do the superficial and deep peroneal nerves originate from?
common peroneal (AKA common fibular)
where do the posterior tibial and sural nerves originate?
tibial nerve
where do the tibial and common peroneal nerve originate?
sciatic nerve
the tibial nerve is __ and the common peroneal is __
tibial - medial (makes sense because the tibia or shin bone is more medial than the fibula)
peroneal - lateral
To inject the posterior tibial, go between the __ malleolus and the Achilles tendon.
Medial malleolus
To inject the sural, go between the __ malleolus and the Achilles tendon.
Lateral malleolus
To inject the deep __, go right between the two tendons (extensor hallucis longus and extensor digitorum longus)
Deep peroneal
To inject the superficial peroneal, go right between the two tendons (extensor hallucis longus and extensor digitorum longus) then aim __
Aim lateral
To inject the saphenous, go right between the two tendons (extensor hallucis longus and extensor digitorum longus) then aim __
Medial
Three complications of ankle blocks are paresthesias, LAST, and __ reaction
Vasovagal reaction
Is foot drop a potential complication of femoral block?
NO, sensory only.
