Blocks at the Wrist Blocks at the Elbow Blocks at the Humeral Level Infraclavicular Techniques Interscalene Approach
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
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