Illustrated Guide: Peripheral Nerve Examination for Medical Students

Preparation for Peripheral Nerve Examination

• Before starting the examination, the examiner should ensure the patient is comfortable and relaxed.
• The examiner should confirm the patient's identity and the purpose of the examination.

Drift Test

• The examiner should ask the patient to hold their arms straight out in front of them, with their palms facing downwards.
• The examiner should then observe for any drift or movement of the patient's hands, which may indicate a cerebellar or pyramidal lesion.
• A positive drift test indicates a lesion in the cerebellar or pyramidal tract.

Tone Assessment

• The examiner should assess tone by feeling the resistance of the patient's muscles to passive movement.

Nerve Innervation

• Thumb abduction is innervated by the Median nerve.
• Finger Flexion is innervated by the Median and Ulnar nerves.

Reflex Tests

• Ankle Clonus is examined by bending the leg at the knee and quickly dorsiflexing the foot.
• Biceps reflex is a test for C5-C6 nerve function.
• Hoffmann's reflex is used to test for Ulnar nerve function.
• In hyperreflexia, clonus may be elicited.
• Ankle plantar flexion is innervated by the S1-S2 nerve.
• Knee extension is innervated by the L2-L4 nerve.

Reflex Tests (continued)

• The Finger Reflex test involves tapping the palmar surface of the middle 3 fingers while they are slightly flexed, and if positive, a contraction of the fingers will occur.
• The Triceps reflex is a test for C7-C8 nerve function.

Vibration Testing

• Examine vibration with a 128 Hz tuning fork, distally, moving proximally only if there is a loss of vibration sense at a certain point.

Adductor Reflex

• The Adductor Reflex is a L2-L4 reflex.