Block, Brachial Plexus: at the Elbow

Paresthesia, nerve stimulator, or field blocks

Median N
-medial to brachial a and biceps tendon
-beneath deep fascia
-needle ~2cm prox to antecubital crease
-5-7cc local "wall"

Radial N
-btwn brachioradialis and brachialis mm
-lateral to biceps tendon
-in front of lateral condyle of humerus
-needle directed slightly cephalad and medial to contact lateral condyle of humerus. 5-7cc "wall"

Ulnar N
-in groove post to medial condyle of hum
-midway btwn olecranon and medial epicondyle
-position: flex arm ~30°
-needle parallel to nerve, below fascia, into groove; 3-5cc

Musculocutaneous N
-superficial, lateral to biceps tendon at elbow crease

Lateral Cutaneous N of Forearm
-subcut injection over course of radial n

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Block, Brachial Plexus: at the Wrist

-for procedure distal to MCP joint
-3-5cc per nerve
-paresthesia, nerve stimulator

Median N
-btwn tendons of flexor palmaris longus and flexor carpi radialis
-deep to deep fascia

Ulnar N
-lateral to flexor carpi ulnaris tendon
-medial to ulnar artery

Radial N
-anatomic snuff box
-or, inject along lateral border of radial artery just above wrist + superficial ring

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Block, Brachial Plexus: Humeral Approach

-Indications: surgery at/below elbow
-2" needle, 7-8 cc local/nerve
-Arm abducted, arm 0-90° flexed. At jnct of upper and middle thirds of upper arm.
-ID humeral artery in upper arm (more distal=nerves more separated)
-Single stick. Needle introduced perpendicularly to skin where Median N. felt --> Ulnar --> Radial --> Musculocutaneous.

-Median N
felt superficially above (anterior to) humeral a.
Finger flexion, thumb adduction, wrist pronation.
Do first ... slowest onset.
Due to anatomical variants (Martin Gruber anastomosis), in 5-8% may get ulnar n type response with electrical stimulation.

-Ulnar N
below Median N (45°?).
Mvmt of prehension by pinky and thumb, wrist supination.

-Radial N
same direction as Ulnar, but deeper in direction of humerus.
If hit bone before finding nerve, rotate hand 30° out to better expose nerve.
Finger, thumb and wrist extension.

-Musculocutaneous N
above Median N and 1" deeper into biceps.
Do last ... quickest onset.

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Block, Brachial Plexus: Infraclavicular Techniques

-Indications:
•surgery of hand, forearm, elbow.
•not for proximal humerus or shoulder
•??occasionally incomplete ulnar n anesthesia; ideally, look for ulnar n stimulation to prevent this.
•40-50ml local

3 techniques:
-Coracoid Approach
-Infraclavicular Fossa
-Raj Approach

-Coracoid Approach
•ID tip of coracoid process
•2cm medial and 2cm inferior
•Usually 3-5cm deep, deep to pectoralis major m. No more than 7cm, even in obese patients.
•Catheter: leave ~5cm in sheath, ropiv 0.2% 4-10ml/hr
-Comments:
•accept only wrist or finger movement
•if get musculocutaneous n: redirect more inferior
•if get subscapular nn (scapular mvmt or serratus mm): redirect more cephalad, superficial
•if get axillary n (deltoid): redirect more superior

-Infraclavicular Fossa
•ID fossa, which is a finger breadth below clavicle (at jnct of middle and lateral thirds) and a finger breadth medial from coracoid
•Direct needle caudally, posteriorly, and medially as if towards superior aspect of 2nd rib
•Usually 1.5-3.0cm deep. Rib is about 5cm deep!

-Raj Approach
•Position supine, head turned contralateral to operative side.
•Draw line from Chassignac's tubercle to proximal axillary a. (approximates course of plexus)
•Needle entry point ~1cm inferior to midpoint of clavicle
•4" needle: direct towards axillary pulse; looking for distal finger twitch

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Block, Brachial Plexus: Interscalene Approach

-For shoulder surgeries
-pt supine, head turned partly away
-stimulating needle: 1"  if learning, o/w 2" OK (larger gauge for easier injection)
-ID interscalene groove, just posterior to SCM
-draw line from cricoid laterally (_not_ along skin crease), towards C6 tubercle
-L fingers 3 and 4 in groove, separated and pushing in to thin tissues
-R hand rests on L.
-needle inserted at intersection of groove with line (between fingers), directed perpendicular to skin, slightly caudal.
-plexus is VERY SUPERFICIAL
-ANY twitch in arm OK, including shoulder; goal is twitch at <0.5 mA
-for shoulder surgery, may need to block medial brachial cutaneous nerve (often leaves sheath just below clavicle) and intercostobrachial nn. independently

Phrenic N - too anterior
Long Thoracic N (serratus anterior) - too posterior
Vertebral A - just anterior to cervical roots

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