Ulnar Nerve Block

1. See Also
   1. Ulnar Nerve
   2. Ulnar Nerve Block at Elbow
   3. Median Nerve Block
   4. Radial Nerve Block
   5. Regional Anesthesia (Nerve Block)
   6. Local Skin Anesthesia
   7. Field Block
   8. Hematoma Block
   9. Digital Block
   10. Point of Care Ultrasound (POCUS)
2. Indications
   1. Anesthesia of Ulnar Nerve distribution distal to wrist
3. Anatomy: Landmarks at medial or ulnar wrist
   1. Ulnar styloid (proximal) or Pisiform Bone (distal)
   2. Flexor Carpi Ulnaris tendon (medial or ulnar aspect)
   3. Ulnar Vein
   4. Ulnar Nerve
   5. Ulnar Artery (lateral or radial aspect)
4. Precautions
   1. Avoid injecting directly into Ulnar Nerve
   2. Avoid injection into ulnar artery
5. Preparation
   1. Needle: 27 gauge 1.5 inch
   2. Skin preparation (e.g. Hibiclens or Betadine)
      1. See Regional Anesthesia
   3. Anesthetic
      1. See Regional Anesthesia for Anesthetic options
      2. Local Anesthetic 2-5 ml (Ultrasound) or 5-10 ml (landmark)
6. Technique: Ultrasound Guided (preferred)
   1. Position
      1. Patient seated
      2. Forearm supinated (palm up)
   2. Ultrasound Probe Position
      1. Transverse to Forearm, over the wrist crease
      2. See Landmarks above
   3. Injection
      1. Insert needle at wrist crease
      2. Direct needle from distal to proximal at 30 degree angle, perpendicular to probe (out-of-plane)
7. Technique: Landmark
   1. Position
      1. Patient seated
      2. Forearm supinated (palm up)
   2. Injection site 1: Palmar branch of the Ulnar Nerve (typical insertion site)
      1. Direct needle from ulnar aspect of wrist towards radial wrist at 45 degree angle
      2. Insert at 1-2 cm proximal to wrist crease, between flexor carpi ulnaris tendon and ulnar artery
   3. Injection site 2: Dorsal branch of the Ulnar Nerve
      1. Distal aspect of ulnar styloid process (dorsum)
      2. Infiltrate 3-4 ml subcutaneously
   4. Warning: Distal Paresthesias with needle with injection
      1. Indicates needle is at Ulnar Nerve
      2. Do not inject here!
      3. Remove needle and reposition
8. References
   1. Pfenninger (1994) Procedures, Mosby, p. 1036-54
   2. Salam (2004) Am Fam Physician 69(4):896 [PubMed]
   3. Yurgil (2020) Am Fam Physician 101(11):654-64 [PubMed]