II. Anatomy: Landmarks (from Anterolateral to Posteromedial)

  1. Anterior Superior Iliac Spine
  2. Sartorius Muscle
  3. Inguinal Ligament
  4. Lateral Femoral Cutaneous Nerve (crosses under Inguinal Ligament)
  5. Iliacus Muscle

III. Indications

  1. Diagnostic to differentiate Meralgia Paresthetica from other causes of anterolateral thigh pain

IV. Precautions

  1. See Regional Anesthesia (Nerve Block)
  2. Avoid injecting directly into nerves

V. 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)

VI. Technique: Ultrasound-Guided (preferred)

  1. Patient position
    1. Supine position
  2. Ultrasound Probe
    1. Linear probe positioned transverse over the inguinal ligament
      1. Lateral probe border parallel with the anterior superior iliac spine (ASIS)
  3. Injection
    1. Needle inserted just lateral to the anterior superior iliac spine (ASIS)
    2. Needle directed in-plane (beneath the Ultrasound probe) at a 30 degree angle
    3. Inject at the perineural space

VII. Technique: Landmarks

  1. Patient position
    1. Supine position
  2. Identify landmarks
    1. Identify anterior superior iliac spine (ASIS)
  3. Injection
    1. Insert needle 2 cm medial and 2 cm distal to ASIS
    2. Angle the needle 30-45 degrees, directed toward the midline
    3. Advance the needle 1 cm and inject
  4. Warning: Distal Paresthesias with needle with injection
    1. Indicates needle is in nerve
    2. Do not inject here!
    3. Remove needle and reposition

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