Pain & Regional

Question 1

an overview of the nerve fibers

Answer 1

Question 2

the myelinated/fast fibers
vs
unmyelinated/slow

Answer 2

fast: A-B & A-d

slow: C

Question 3

epicritic sensations such as touch, pressure and proprioception

Answer 3

A-B

Question 4

Sharp pain/first pain/acute pain

Answer 4

A-d

Question 5

protopathic (noxious) stimuli fibers

Answer 5

A-d

Question 6

major neurotransmitter released from A-δ fibers

Answer 6

glutamate

binds to AMPA receptors on the postsynaptic membrane

Question 7

dull, poorly localized sensations

Answer 7

C fibers

Question 8

Second Pain or “Chronic”

Answer 8

C fibers

Question 9

Transmits protopathic sensations of pain, temperature, and touch

Answer 9

C fibers

Question 10

major NT released from C Fibers

Answer 10

Substance P

binds to NK-1r on postsynaptic membrane (resulting in the lingering sensation after a burn)

Question 11

Non-painful vs painful
stimulation

Answer 11

Non-painful: large diameter nerve fibers, A-β (beta)

Painful: smaller diameter nerve fibers, A-δ (delta) & C fibers

“small D.A.C. open”

Question 12

Nociceptor types

Answer 12

1. Mechanonociceptors: mechanical stimulation (pressure, vibration, movement) (i.e., pinch and pin prick)
2. Silent: inflammation
3. Polymodal mechanoheat & “thermoreceptors:” excessive pressure and/or temperature.

Question 13

“Thermoreceptors” respond to …

Answer 13

1. extremes of temperature (> 42°C and < 18°C)
2. alogens (pain-producing substances or chemical mediators of pain)

Question 14

Most prevalent, most sensitive nociceptors

Answer 14

polymodal mechanoheat

Question 15

Lumbar plexus

Answer 15

femoral & obturator (L2-L4)

lateral femoral cutaneous (L2-L3)

Question 16

Femoral nerve provides:

Answer 16

• Motor & sensory innervation to anterior thigh
• Sensory to medial leg
• Sole motor innervation to quads

Question 17

“3 in 1 block”

Answer 17

femoral, obturator, accessory obturator

Question 18

blocked in the PENG block (hip)

Answer 18

Articular branches of femoral nerve

Question 19

LIA block (knee) targets

Answer 19

• posterior division of femoral nerve
• Branches innervate the anterior knee capsule
• Vastus lateralis, intermedius, medialis

Question 20

the sensory branch of the femoral nerve

Answer 20

saphenous

Question 21

Interscalene block
coverage

Answer 21

• superior trunk (C5, C6, maybe C7)
• Not great coverage for C8-T1
• ulnar nerve not covered
• Weakens bicep; decreased sensation in forearm

Indications: upper arm/shoulder (not good for hand/wrist)

Question 22

Interscalene block
Landmarks

Answer 22

sternocleidomastoid, clavicle, cricoid cartilage, EJ

Question 23

Interscalene block
SEs

Answer 23

• pneumo
• recurrent laryngeal block
• central nerve block
• vertebral artery injection
• Horner’s syndrome (ptosis, miosis, anhidrosis)
• phrenic nerve block

Question 24

Avoid these blocks with severe pulmonary disease

Answer 24

IS & supraclav

Question 25

block carries risk of chylothorax

Answer 25

infraclav

Question 26

BP coverage for each UE block

Answer 26

* IS: superior trunk * SC: all divisions * IC: level of the cords * AX: cords where they regroup in terminal branches

Question 27

Which block spares the ulnar nerve? Which spares the musculocutaneous?

Answer 27

IS: no ulnar Ax: no musc.

Question 28

Supraclavicular block landmarks

Answer 28

clavicle; subclavian pulse; “corner pocket” between artery, plexus, and first rib

Question 29

Intercostobrachial nerve block is not part of the BP bc it blocks at....

Answer 29

T2

Question 30

Considered a "field block"

Answer 30

Radial n.

Question 31

Landmark for median v. ulnar block

Answer 31

median: flexor carpi **radialis** tendon ulnar: flexor carpi ulnaris tendon

Question 32

How to do a Bier block

Answer 32

1. 2 IVs (each arm), 2 tourniquets (proximal/distal), 20 min min, 2 hr max 1. Tourniquets as proximal as possible; IVs as distal as possible 1. Extremity elevated and esmarch bandage applied 1. Check pulse 1. Inject SLOWLY over 90 seconds; do not want venous pressure > tourniquet pressure 1. Arm: 40-50 ml of 0.5% lido

Question 33

Do not use this for a bier block

Answer 33

No epinephrine (ischemia risk)

Question 34

Adductor canal blocks coverage ## Footnote sensory only

Answer 34

* knee and medial leg * Quads less affected than femoral block * saphenous nerve & posterior obturator nerve ✅ knee scope & supplement foot/ankle surgery

Question 35

Adductor canal blocks landmark

Answer 35

* femoral artery & vein * sartorius muscle (medial) * adductor magnus (posterior) * vastus medialis (anterior)

Question 36

Nerve injuries for positions in lithotomy

Answer 36

* Sciatic (stretch) * Common peroneal (compress lateral fibula head) * Femoral (compression) * Saphenous * Obturator

Question 37

# Lithotomy Hip flexion & nerve injury

Answer 37

* > 90 deg of trunk = stretch inguinal ligaments * Branches of lateral femoral cutaneous nerves pass through these ligaments * become pinched/ischemic within the stretched ligament

Question 38

Being in lithotomy this long increases risk of: -common peroneal injury -compartment syndrome

Answer 38

CP: > 4 H Compartment Syndrome: >5 H