UPPER EXTREMITY BLOCKS (SYNOPSIS)

JOHN BRAMHALL PhD MD
UNIVERSITY OF WASHINGTON

The upper extremity is innervated via the brachial plexus, formed by anastomosis and ramification of the ventral nerve roots C5-T1. The roots combine to form 3 trunks, these course over the first rib then divide into 3 cords which closely surround the subclavian artery laterally, medially and posteriorly. These then branch into terminal (peripheral) nerves.

lateral - musculocutaneous & median n.
medial - ulnar & median n.
posterior - radial n.

[click here for picture of brachial plexus, and here for more detailed descriptions of blocks]

Blocks of the brachial plexus are worth perfecting, they are commonly used. They provide anesthesia and profound muscle relaxation for surgery, and post-surgical analgesia.

INTERSCALENE (root)
SHOULDER
Supine, arms by sides, head turned slightly away.
Identify SCM lateral border, then groove between anterior and middle scalenes.
May palpate Chassaignac’s tubercle, may palpate subclavian artery.
Probe interscalene groove at level of cricoid cartilage.

SUPRACLAVICULAR (trunk)
UPPER ARM, ELBOW & DISTAL ARM
Supine, arms by sides, head turned slightly away.
Identify SCM lateral border, then groove between anterior and middle scalenes.
May palpate Chassaignac’s tubercle, may palpate subclavian artery.
Mark the skin just posterior to mid-point of clavicle (or over subclavian pulse).
Probe down to the rib (aiming for the feet).

INFRACLAVICULAR (cord)
UPPER ARM, ELBOW & DISTAL ARM
Supine, arm abducted.
Mark the skin 2 cm below mid-point of clavicle.
Probe towards axilla at 45 degree angle.

AXILLARY (branch)
DISTAL ARM & HAND
Supine, arm abducted, elbow flexed and rotated upwards, head turned slightly away.
Palpate axillary artery high under pectoralis m.
Probe adjacent to artery.

IV/BIER BLOCK (branch)
HAND
Small IV in hand vein.
Raise arm, exsanguinate (elastic bandage), double cuff.
Inflate distal cuff, inflate proximal cuff, deflate distal cuff.
Inject agent, remove IV
For Bier block, 1 hour duration, use lidocaine 0.5%, 50 cc.

WRIST BLOCK (branch)
HAND
Ulnar nerve: between flexor carpi ulnaris and palmaris longus tendons.
Median nerve: between flexor carpi radialis and palmaris longus tendons.
Radian nerve: skin wheal at base of thumb.

DRUGS
Use 20-30 cc solution, include 1/200,000 epinephrine.
4 hour block: lidocaine 1.5%, mepivacaine 1.25%
8 hour block: bupivacaine 0.375%

PEARLS
Anatomic (often bombs).
Paresthesia (no paresthesia, no anesthesia).
Nerve stimulation (negative electrode to needle, be gentle - <1 mA)
Continuous catheter technique (interscalene, infraclavicular and axillary blocks).
Avoid, at all costs, injecting bupivacaine IV!

TESTING
push-pull-pinch-pinch!

[click here for picture of upper extremity sensory dermatomes]

TOUCH-UPS
Ulnar n.: Sulcus of medial epicondyle of humerus.
Median n.: Just medial to brachial artery.
Radial n.: In cleft between biceps tendon and brachioradialis m.
Musculocutaneous n.: In body of coracobrachialis m.