Lower body blocks (exam 2)

Question 1

Analgesia refers to?

Answer 1

pain relief

Question 2

Anesthesia refers to?

Answer 2

allows you to perform surgery (loss of consciousness with GA) but loss of consciousness is not necassary.

Question 3

The lumbar plexus supplies motor and sensory innervation to??

Answer 3

anterior portion and cutaneous sensory medial lower leg (saphenous nerve).

Question 4

Lumbar plexus arises from what roots?

Answer 4

L1-L4

Question 5

**3 major nerves make up the Lumbar plexus, what are they?

Answer 5

Lateral Femoral Cutaneous L2-L3 (M&M says L1-3)

Obturator L2-L4 (Freq. injured in pelvic surg)

Femoral L2-L4 (largest branch of LP)

Question 6

Sacral Plexus is derived from what rami?

Answer 6

anterior rami of the L4 and L5 and S1-S4 nerves.

Question 7

What three nerves are included in the Sacral plexus block?

Answer 7

Sciatic L4-S3 (largest nerve trunk in the body)

Posterior cutaneous nerve (S1-3)

Terminal branches-tibial and common peroneal

Question 8

4 major nerves that supply all of the lower extremity?

Answer 8

Lateral femoral cutaneous nerve

Femoral nerve (anterior crural nerve)

Obturator nerve

Sciatic nerve

(Posterior cutaneous nerve of thigh (S1-S3)

Question 9

Does the Lumbar Plexus Block supply complete anesthesia of the lower extremity?

Answer 9

Does not supply complete anesthesia of lower extremity because it cannot achieve blockade of the sacral roots that supply the sciatic nerve

Question 10

Posterior Lumbar Plexus block:
position?
landmark?

Answer 10

Position: Lateral
Landmarks: 4cm lateral to L4 Spinous processes

Question 11

Technique for Posterior Lumbar Plexus block?

Answer 11

A line is drawn through the lumbar spinous processes and then a line is drawn through iliac crests (at level of L4)

Palpate superior iliac spine and draw another line cephalad (parallel to spinous process line).. (Point of entry will be b/w these 2 parallel lines)

Question 12

What does the femeral nerve innervate?

Answer 12

Innervates main hip flexors, knee extensions & provides much of the sensory innervation of the hip & thigh

Question 13

What is a 3-in-1 block

Answer 13

The term 3-in-1 block refers to anesthetizing the femoral, lateral femoral cutaneous, and obturator nerves with a single injection below the inguinal ligament (not always successful- it is difficult to get all 3 nerves with one single injection)

Question 14

Femoral nerve block alone will not provide surgical analgesia for ? (what 3-4 parts of the leg)

Answer 14

hip, thigh, knee, and/or ankle

Question 15

Femoral nerve block, does it have high risk or low risk of complications?

Answer 15

relative low risk?

Question 16

Femoral nerve block Technique? What do you want to see elicited with the PNS?

Answer 16

Palpate femoral artery at level of inguinal ligament (may use US to view structures- femoral vein, artery & femoral nerve- a spindle shaped structure with a “honey comb” texture)

quadriceps twitch should be elicited with PNS

Question 17

Regarded as a femoral nerve block only?

Answer 17

Femoral 3-in-1 block

Question 18

With a femoral 3-in-1 block where does it produce anesthesia?

Answer 18

anterior portion of the upper leg and medial calf and results in inability to abduct the leg or extend the lower leg.

Question 19

Anesthesia- what would a definition be?

Answer 19

procedure can occur (they are not asleep) and post operative you have pain relief.

Question 20

lateral femoral cutaneous nerve block is typically used as a supplement to what nerve block?

Answer 20

femoral nerve block

Question 21

Indications for the use of a lateral femoral cutaneous nerve block?

Answer 21

Used in conjunction with blockade of other nerves to provide anesthesia for surgical procedures involving the leg.

Alone, it is used to provide anesthesia for superficial procedures on the lateral thigh, such as skin grafting.

It is also used in the diagnosis and treatment of meralgia paresthetica, a pain syndrome involving the lateral femoral cutaneous nerve.

Question 22

femoral cutaneous nerve block, what structure do you pass through that creates a pop??

Answer 22

The fascia lata is identified by a “release” or a “pop” as a needle passes through it.

Question 23

What nerve block in practice has no side effects or complications?

Answer 23

Lateral femoral cutaneous nerve block!

Question 24

Obturator nerve, is it sensory or motor nerve?

Answer 24

Both a motor and a sensory nerve

Sensory branches to the hip & knee joints, medial thigh

Innervates the adductors of the hip

Question 25

When is the obturator nerve usually blocked? (in conjunction with)

Answer 25

The obturator nerve is usually blocked in conjunction with the lateral femoral cutaneous, femoral, and sciatic nerves for surgical procedures on the leg.

Question 26

When is a block of the obturator nerve alone used?

Answer 26

The block used alone is useful in aiding in the diagnosis and treatment of pain syndromes involving the hip joint, as well as relieving adductor spasms of the hip.

Question 27

What nerve stimulation do you want to see if using an obturator nerve block?

Answer 27

thigh adduction

Question 28

What do you need to pay careful attention to with an obturator nerve block?

Answer 28

Careful attention to the bony landmarks and the depth of needle insertion reduces the chance of needle placement into surrounding structures such as the bladder, rectum, vagina, or spermatic cord.

Question 29

Sciatic nerve block is mostly indicated for?

Answer 29

procedures involving the hip, thigh, knee, lower leg & foot

Question 30

you can combine a sciatic nerve block with what other nerve block to provide complete anesthesia and post-op analgesia for lower extremity surgery? (2)

Answer 30

lumbar plexus block or femoral 3-in-1 block.

Question 31

What muscle twitch do you want to elicit with a Sciatic block?

Answer 31

plantar or dorsiflexion is elicited (plantar flexion- distal ankle, foot or toes… or foot inversion)

Question 32

Side effect of sciatic nerve block can be what two things?

Answer 32

Mild hypotension due to sympathetic fibers being blocked

Residual dysesthesias (abnormal sensation) usually improving 1-3 days

Question 33

Sciatic nerve divides into what two other nerves?

Answer 33

tibial and common peroneal nerve

Question 34

What do you want to avoid with an ankle block?

Answer 34

Avoid excessive LA volume and avoid epinephrine (to avoid risk of ischemic complications)

Question 35

Ankle block typically requires how many injections?

Answer 35

5 seperate injections

Posterior tibial nerve- direct continuation of tibial
Deep peroneal nerve- runs off common peroneal
Superficial peroneal nerve- runs off common peroneal
Sural nerve- branch of tibial
Saphenous nerve (terminal branch of femoral)- not a part of sciatic system