Regional Anesthesia: Bony Landmarks

Basic, Basic Sciences

All regional nerve blocks use anatomic landmarks and many of them rely on bony landmarks. Below is a list of regional nerve blocks with the insertion points as described using bony landmarks. For the purposes of this keyword, landmarks are only listed for those blocks that have bony landmarks; this is not a complete list of landmarks for all regional nerve blocks.

Head/Upper Extremity Blocks:

Deep Cervical Plexus Block: Line between C6 transverse process (Chassaignac’s tubercle) and mastoid process

Interscalene – Level of Chassaignac’s tubercle between anterior and middle scalene muscles

Supraclavicular – Midpoint of clavicle in interscalene groove

Infraclavicular –2 cm medial and 2 cm caudad from coracoid process 

Forearm – 

At wrist: Radial nerve - radial artery lateral border 2 cm proximal to wrist, medial nerve 2 cm proximal to wrist flexor crease, ulnar nerve just proximal to ulnar styloid process 

Lower Extremity Blocks:

Femoral – Line from anterior superior iliac spine and pubic symphysis, midpoint is target

Sciatic – Labat’s classic approach: line from greater trochanter to PSIS, line from greater trochanter to sacral hiatus, line perpendicular from midpoint of first line to intersection of second for insertion

Ankle – Posterior tibial nerve: posterior to medial malleolus; saphenous nerve: circumferential injection at level of medial malleolus from Achilles tendon to tibial ridge; superficial peroneal nerve: tibial ridge laterally toward lateral malleolus; sural nerve: level of lateral malleolus toward Achilles tendon

Truncal Blocks:

Lumbar Plexus – Intersection of horizontal line from midline at level of superior border of posterior iliac crest and vertical line from posterior superior iliac spine extending superiorly (usually 5 cm lateral of midline)

Obturator – 2 cm lateral and inferior from pubic tubercle, insert until contact with pubic ramus OR midpoint of line between medial edge of femoral pulse just below inguinal ligament to long adductor muscle, insert at midpoint

Fascia Iliaca – Lateral third of the line between ASIS to pubic tubercle

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2017

Year asked

Author
Eric Ness, MD