Regional/Nerve distributions Flashcards
What is the innervation to the lower extremity?
L2-S3
What nerves form the lumbar plexus?
L2-L4
What nerve does the saphenous nerve come from?
Femoral nerve (L2-L4)
What nerve is responsible fro the medial portion of the leg, ankle and the posterior medial portion of the foot?
Saphenous nerve
What gives sensation to the posterior thigh?
Posterior cutaneous nerve of the thigh (S1-S3)
What nerves provide sensation to the lateral portion of the leg?
Lateral sural cutaneous and superficial peroneal from peroneal division
What supplies the posterior portion of the leg and lateral portion of the heel and foot?
Lateral calcaneal and lateral dorsal cutaneous via the sural nerve
What nerve supplies sensation over the medial heel?
Medial calcaneal nerve from the tibial
Where is a popliteal block done?
6-7 cm above the popliteal crease either laterally between the vastus lateralis and biceps femoris or posteriorly between semitendinosus and biceps femoris
Where is the saphenous nerve block done?
At the level of the medial malleolus
What are the 5 nerves that need to be blocked for an ankle block?
Posterior tibial nerve Sural nerve Deep peroneal Superficial peroneal Saphenous
Where do you block the posterior tibial nerve?
Posterior to tibial artery at level of medial malleolus
Where do you block the sural nerve?
Posterior to the lateral malleolus and lateral to calcaneus
Where do you block the deep peroneal nerve?
lateral to anterial tibial artery on the anterior portion of the ankle deep to the fascial planes.
Where do you block the superficial peroneal nerve?
Lateral malleolus to anterior tibia
Which antiplatelet/anticoag can be continued before neuraxial anesthesia?
Aspirin
What is an indication for IV regional anesthesia?
Extremity surgery of brief duration
What are the contraindications to IV regional anesthesia?
Sickle Cell disease Allergy to local Presence of infection at the site Inability to place catheter Patient refusal
What are the relative contraindications to IV regional anesthesia?
Seizure disorder
High grade heart block
Bleeding disorders
Hepatic failure
What are the most commonly used locals in IV regional anesthesia?
Procaine and lidocaine
After how many minutes is the local less likely to disseminate systemically if tourniquet pressure is lost?
20 minutes
What are the signs of local toxicity?
Ringing in the ears, feeling bad, numbness around the mouth, headache, metallic taste in the mouth
How high should the tourniquet pressure be?
100 mmHg above systemic
What are the symptoms of local toxicity?
muscle twitching, LOC, grand mal seizure, vascular collapse
What is the treatment for local toxicity?
ABCs
BZD or thiopental for anticonvulsant
Bretylium or cardioversion for ventricular arrythmias
Intralipid for bupivacaine toxicity
What is the most common cause for regional anesthesia failure?
Prolonged tourniquet time
What medication can be used to raise the seizure threshold?
BZD
