Nerve Block: Serratus Anterior


  • Injection of local anesthetic around the thoracic intercostal nerves to provide regional anesthesia to the anterolateral chest wall


  • Rib fractures [1]
  • Rib contusions


  • Overlying soft tissue infection
  • Allergy to local anesthetic

Equipment Needed

  • Ultrasound (linear transducer) w/ sterile probe cover
  • Sterile gloves
  • Chlorhexidine or betadine solution
  • 1% lidocaine with epinephrine in syringe with 27-gauge needle (for skin wheel)
  • 0.5% or 0.25% bupivacaine in 30 ml syringe.
  • 18 gauge blunt needle
  • 22-25 gauge peripheral nerve block needle with extension tubing
    • Alternatively, 22g spinal needle with IV extension tubing


  • Position patient in supine or lateral decubitus position (injured side up)[2]
  • Sterilize skin w/ antiseptic solution
  • Inject wheal of lidocaine into injection site
  • Place ultrasound probe lateral to the nipple in transverse orientation
  • Find the serratus anterior muscle overlying the ribs in the lateral chest wall
  • Using the in-plane technique, advance needle with dominant hand
  • Identify the pleural line prior to inserting the needle
  • Advance the needle toward the rib (you will feel a pop once through the fascia)
  • Connect tubing to needle and syringe.
  • Push 2-3 cc to confirm placement between the serratus anterior and latissimus dorsi. The two should separate freely.
  • Inject the remaining anesthetic


  • Nerve injury
  • Vascular injury
  • Rebound pain

See Also

External Links




  1. Southgate SJ, Herbst MK. Ultrasound Guided Serratus Anterior Blocks. [Updated 2021 Jul 31]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: