Examination of the radial nerve

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Anatomy[edit | edit source]

The radial nerve (C5–C7) spreads along the lateral side of the arm, the sulcus nervi radialis on the humerus runs further to the dorsum of the arm. It has both a sensory and a motor component, so it is a mixed nerve.

Motor innervation area[edit | edit source]

Sensitive innervation area[edit | edit source]

The radial nerve mainly innervates the dorsal side of the forearm, rather its radial half. Next, part of the back of the hand, II. and III. finger.

Examination in paresis[edit | edit source]

Clenched fingers test[edit | edit source]

We ask the patient to join the hands with the palms together with the fingers extended. Thanks to the weakening of the extensors, the fingers on the paresis side fall into flexion.

Clenched fist test[edit | edit source]

In classic clenching of non-paretic muscles, a compensatory extension occurs in the wrist when clenching into a fist. We invite the patient to clench his hand into a fist, due to the weakened extensors, a normal compensatory extension reaction will not occur, but instead a flexion of the wrist and subsequent clenching into a fist.

Extensor test[edit | edit source]

The patient is asked to place his hand on the table so that the wrist and fingers are off the table and hang down freely. Next, we want him to do wrist extension, MP, PIP and DIP. Due to the weakening of the PIP and DIP extensors, they assume a flexion posture or cannot manage extension at all.

Clinical picture of the lesion[edit | edit source]

A typical symptom of a radial nerve lesion is the so-called teardrop hand, when the forearm is in slight pronation, the hand falls into palmar flexion at the wrist, and the fingers and thumb hang weakly down.

Causes of the lesion[edit | edit source]

The radialis nerve is most commonly affected by trauma. Damage is often found in the sulcus nervi radialis, when the extensors of the hand and wrist are affected by the mechanism of a fracture or long-term pressure, e.g. while sleeping. In the event of a violation in the axilla region, the function of the triceps brachii muscle is damaged, this often happens due to the oppression of the axillaris nerve, along with damage to other nerves of the upper limb.

Links[edit | edit source]

Related articles[edit | edit source]

Použitá literatura[edit | edit source]

  • AMBLER, Zdeněk. Základy neurologie :  [učebnice pro lékařské fakulty]. 7. edition. Galén, c2011. ISBN 9788072627073.
  • OPAVSKÝ, Jaroslav. Neurologické vyšetření v rehabilitaci pro fyzioterapeuty. 1. edition. Univerzita Palackého, 2003. ISBN 80-244-0625-X.
  • MUMENTHALER, Marco – BASSETTI,. Neurologická diferenciální diagnostika. 1. edition. Grada, 2008. ISBN 978-80-247-2298-6.
  • FULLER, Geraint. Neurologické vyšetření snadno a rychle. 1. edition. Grada, 2008. ISBN 978-80-247-1914-6.