Blocks 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

Blocks 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

Blocks at the Humeral Level:

• 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.

Infraclavicular Techniques:

Overview

• 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

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