Nerve Injury of Upper Limb

Courtesy: Nabile Ebraheim, Chairman, Dept of Orthopaedic Surgery, University of Toledo, USA

The upper limb contains several major peripheral nerves responsible for muscle contraction, reflex activity, and sensation. A systematic motor and sensory examination helps in rapid localization of nerve injuries.

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Major Nerves of the Upper Limb

 

1. Radial Nerve

Motor Function

• Wrist extension

• Thumb extension

Motor Test

• Ask the patient to extend the wrist and thumb against resistance

Sensory Innervation

• Posterior cutaneous nerve of arm

• Posterior cutaneous nerve of forearm

• Lower lateral cutaneous nerve of arm

• Superficial radial nerve (sensory only)

The superficial radial nerve supplies sensation to most of the dorsum of the hand.

Sensory Test

• Dorsal web space between the thumb and index finger

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2. Ulnar Nerve

Motor Function

• Intrinsic hand muscles (interossei)

Motor Test

• Little finger abduction against resistance

Sensory Innervation

• Palmar and dorsal aspects of:

  • Little finger

  • Ulnar half of ring finger

Sensory Test

• Distal ulnar aspect of the little finger

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3. Median Nerve

Motor Function

• Thumb opposition

• Thumb abduction

• Precision pinch

Motor Tests

• Thumb–index finger pinch

• Opposition of thumb

• Abduction of thumb (APB function)

Sensory Innervation

• Palmar surface of:

  • Thumb

  • Index finger

  • Middle finger

  • Radial half of ring finger

• Via:

  • Palmar cutaneous branch

  • Common and proper digital nerves

Sensory Test

• Distal radial aspect of the index finger

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4. Axillary Nerve

Motor Function

• Shoulder abduction via deltoid muscle

Motor Test

• Abduction of shoulder against resistance

Sensory Innervation

• Skin over the lateral shoulder region

Sensory Test

• Lateral upper arm (deltoid patch)

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5. Musculocutaneous Nerve

Motor Function

• Supplies:

  • Biceps brachii

  • Brachialis

  • Coracobrachialis

• Continues distally as the lateral cutaneous nerve of forearm

Motor Test

• Elbow flexion against resistance (biceps)

Sensory Innervation

• Lateral aspect of the forearm (ventral surface)

Sensory Test

• Lateral forearm

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Quick Clinical Summary Table