Myotomes and Differentiating Nerve Lesions
UPPER LIMB
- Shoulder Abduction – C5 (axillary)
- Shoulder Adduction – C678
- Elbow Flexion – C5 (musculocutaneous)
- Elbow Extension – C7 (radial)
- Wrist Flexion & Extension – C67 (radial)
- Finger Flexion – C8 (median)
- Finger Extension – C7 (radial – posterior interosseous)
- Finger Abduction – T1 (ulnar)
- Abductor pollicis brevis – T1 (median)
Sorting out Muscles
- biceps vs brachioradialis (both test C56: tests musculocutaneous nerve vs radial, note biceps jerk)
- abductor pollicis brevis vs first dorsal interosseous (both T1: test median vs ulnar)
- abductor pollicis brevis vs flexor pollicis longus (both median but abductor polis brevis supplied after the carpal tunnel)
LOWER LIMB
- Hip Flexion – L2 (femoral)
- Hip Extension – L5 (inferior gluteal)
- Knee Extension – L34 (femoral)
- Knee Flexion – S1 (sciatic)
- Ankle dorsiflexion – L4 (deep peroneal)
- Ankle plantarflexion – S1 (tibial)
- Great toe flexor – L5 (deep peroneal)
Sorting out Muscles
- ankle dorsiflexors vs ankle inversion (both L4: tests deep peroneal vs tibial)
- ankle dorsiflexors vs ankle evertors (both common peroneal nerve tests: tests superficial vs deep)
- ankle dorsiflexors vs great toe flexor (both deep peroneal nerve tests L4 vs L5)
Critical Care
Compendium
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC
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Hi. The comment “ankle dorsiflexors vs ankle inversion (both L4: tests deep peroneal vs tibial)” is incorrect. Inversion is testing L5 via the tibial nerve, not L4.