Greater occipital nerve block (ultrasound-guided)

Last revised by Rohit Sharma on 22 Feb 2024

A greater occipital nerve block is a diagnostic and/or therapeutic procedure in which the medial, sensory branch from the second cervical spinal nerve is targeted with local anesthesia.  

  • cellulitis or abscess in the site of injection

  • known allergy to local anesthetics

Approaches at the level of the superior nuchal line and at the level of C2 have been described 5; the following discussion will describe the performance of the latter technique.

The ultrasound machine should be optimally positioned for ergonomic visualization during the procedure. The patient is positioned prone or seated with the neck flexed forward. 

The relevant anatomy is first defined with a high frequency linear probe placed in a transverse orientation inferior to the external occipital protuberance and then slowly sliding the transducer caudad until the spinous process of the second cervical vertebra (C2) is identified by virtue of its characteristic dorsal bifurcation into two distinct tubercles 2.

The transducer should then be moved laterally, rotating the lateral end of the transducer slightly cephalad to assume an oblique position parallel to the obliquus capitis inferior muscle 4. The more superficial semispinalis capitis muscle should then be identified; the greater occipital nerve is located in the fascial plane between, and should appear ovoid and uniformly hypoechoic 3. Color or power Doppler should be used to ensure the identified structure does not represent a blood vessel. Care should be taken to identify the vertebral artery which is typically found coursing laterally and deep to the obliquus capitis inferior muscle, as well as the more medial dorsal root ganglion of C2.  

After appropriate skin cleansing and equipment preparation, a 5 cm needle is inserted at the medial or lateral margin of the transducer and the tip advanced in-plane into the intramuscular fascial plane 6. After a negative aspiration test 3–5 mL of local anesthetic is slowly injected, ensuring characteristic and appropriate distention of the fascial plane and circumferential spread around the nerve.

Complications of the greater occipital nerve block may include:

  • local infection

  • neural injury

  • vascular injury

  • subarachnoid injection 7

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