I. Indications
- Anesthesia of Median Nerve distribution
II. Contraindications (Relative)
III. Precautions
- Avoid Median Nerve
- Injection is harmful if improperly done
IV. Anatomic relationships
- Flexor carpi radialis (radial side)
- Median Nerve
- Palmaris Longus (Ulnar side)
- Forms palmar aponeurosis at midline of wrist
- Opose thumb and 5th finger to find palmaris longus
V. Preparation
- Needle: 27 gauge 1.5 inch
- Anesthetic: Lidocaine 1%: 2-5 ml
VI. Technique
-
Wrist position
- Dorsiflex wrist to 30 degrees resting on towel roll
- Injection site
- Radial side of following landmark
- Wrist midline if palmaris longus absent or
- Palmaris longus tendon
- Find by opposing thumb with pinky or
- Flex middle finger against resistance
- Proximal wrist crease
- Radial side of following landmark
- Needle insertion
- Apply antiseptic to skin (e.g. Betadine)
- Aim 45 degrees distally toward middle-ring finger
- Insert needle 1-2 cm until no resistance
- Do not inject if Paresthesias (see below)
- Warning: Distal Paresthesias with needle with injection
- Indicates needle is at Median Nerve
- Do not inject here!
- Remove needle and replace further to the ulnar side
VII. References
- Pfenninger (1994) Procedures, Mosby, p. 1036-54
- Salam (2004) Am Fam Physician 69(4):896 [PubMed]
