Ulnar

by | Aug 22, 2021

Indications

  • Hand laceration or injury
  • Boxer’s fractures

Contraindications

  • Infection overlying injection site
  • Allergy to local anesthetic
  • Vascular injury/injection: the ulnar nerve runs with the ulnar artery, ensure a negative aspiration prior to injection

Equipment

  • 5cc of local anesthetic of choice
  • 25-27G needle
  • Saline Flush
  • Cleansing solution
  • Ultrasound with high-frequency linear transducer
  • Ultrasound transducer sterile cover

Ultrasound

Approach #1 (Elbow)

  1. Position the patient with the arm extended, or with the forearm across the patient’s abdomen, with elbow flexed to 90 degrees
  2. Place the transducer transversely 2-3cm proximal to the elbow at the medial of the upper arm
  3. The ulnar nerve is seen superficial to the triceps muscle and typically does not accompany an artery, in contrast to the median nerve
  4. Surround target with local anesthetic

Approach #2 (Wrist)

  1. Position the forearm abducted from the patient, supinated
  2. Place the probe transversely 3-4cm proximal to the wrist

  1. Immediately ulnar to the artery will be the ulnar nerve
  2. If the artery and nerve are too close, trace proximally to separate the nerve from the artery
  3. Surround target with local anesthetic

Examples

In-plane ulnar nerve block with needle seen entering from the ulnar aspect, depositing anesthetic first in soft tissues, followed by injection adjacent to the ulnar nerve (*). The ulnar artery can be seen pulsating screen left (radial to) the nerve.

 

Source

  1. The POCUS Atlas