The human hand is an extraordinary organ of precision, power, and expression. It allows us to write, hold, gesture, and perform delicate movements that define our individuality. However, the proper functioning of the hand depends on a complex network of nerves — primarily the ulnar, median, and radial nerves. When any of these nerves are damaged, compressed, or injured, the result is known as a hand nerve lesion. These lesions can drastically impair hand function, leading to characteristic deformities such as Claw Hand, Wrist Drop, and Hand of Benediction.
In this article, we will explore these three major types of nerve injuries in detail — their anatomy, causes, symptoms, clinical presentations, and treatment approaches — to understand how the loss of nerve function “speaks louder than words.”
1. Understanding the Nerves of the Hand
The hand’s sensory and motor control mainly depends on three peripheral nerves:
- Ulnar Nerve – supplies the little finger, part of the ring finger, and many intrinsic hand muscles.
- Median Nerve – controls most forearm flexors and the thumb’s fine motor movements.
- Radial Nerve – provides motor function to the extensors of the wrist, fingers, and thumb.
Each of these nerves runs a unique course through the arm and forearm and is vulnerable to injury at specific points. Damage to any of them leads to characteristic hand deformities that reflect the specific muscles that have lost their nerve supply.
2. Ulnar Nerve Injury – The “Claw Hand”
Anatomy and Function
The ulnar nerve originates from the brachial plexus (C8–T1 roots) and travels down the arm behind the medial epicondyle of the humerus, commonly known as the “funny bone.” It continues into the forearm and hand, supplying several intrinsic muscles responsible for fine finger movements.
Causes of Injury
Common causes of ulnar nerve injury include:
- Fracture or dislocation near the medial epicondyle of the humerus.
- Compression at the cubital tunnel (elbow region).
- Entrapment at the Guyon’s canal in the wrist (common in cyclists).
- Direct trauma or prolonged pressure on the elbow or wrist.
Clinical Features: Claw Hand
The hallmark sign of ulnar nerve injury is Claw Hand Deformity.
In this condition, there is hyperextension of the metacarpophalangeal joints (MCP) and flexion of the interphalangeal joints (IP) of the fourth and fifth digits (ring and little fingers).
This happens because:
- The lumbrical and interosseous muscles (supplied by the ulnar nerve) are paralyzed.
- The extensor digitorum (supplied by the radial nerve) acts unopposed at the MCP joint, causing hyperextension.
- The flexor digitorum profundus continues to flex the IP joints.
The result is a hand that appears clawed — particularly at rest.
Other Symptoms
- Weak grip and loss of dexterity.
- Sensory loss over the little finger and half of the ring finger.
- Difficulty performing fine movements such as writing, buttoning, or pinching.
Location of Lesion
The image notes “Distal ulnar nerve”, meaning the injury occurs below the elbow, often at the wrist.
Treatment
Treatment depends on the cause and severity:
- Splinting to prevent contractures.
- Physiotherapy to maintain joint mobility and strengthen muscles.
- Surgical decompression or nerve repair in severe cases.
3. Radial Nerve Injury – The “Wrist Drop”
Anatomy and Function
The radial nerve arises from the posterior cord of the brachial plexus (C5–T1 roots) and supplies all the extensor muscles of the arm and forearm. It travels along the spiral groove of the humerus, making it vulnerable to injury, especially in mid-shaft humeral fractures.
Causes of Injury
- Fracture of the mid-shaft humerus (most common cause).
- Improper use of crutches (Crutch palsy).
- Prolonged compression during sleep (“Saturday night palsy”).
- Lacerations or penetrating trauma to the arm.
Clinical Features: Wrist Drop
When the radial nerve is injured, the extensor muscles of the wrist and fingers become paralyzed.
As a result, the person cannot extend the wrist or fingers, leading to a characteristic posture called “Wrist Drop.”
In this position:
- The wrist hangs flaccidly.
- The hand cannot lift upward.
- Grip strength decreases because a stable wrist position is essential for effective grasping.
Other Symptoms
- Weakness in elbow extension (if injury is high up).
- Loss of sensation over the posterior arm, forearm, and dorsal hand (especially the area between the thumb and index finger).
- Decreased grip strength and difficulty in lifting objects.
Location of Lesion
According to the image, the “superficial branch of the radial nerve” is affected — usually a distal lesion, leading primarily to motor deficits.
Treatment
- Wrist splints to maintain extension and prevent contracture.
- Physiotherapy and electrical stimulation to promote recovery.
- Nerve grafting or tendon transfer may be considered in chronic cases.
4. Median Nerve Injury – The “Hand of Benediction”
Anatomy and Function
The median nerve originates from both the lateral and medial cords of the brachial plexus (C5–T1 roots).
It supplies most of the forearm flexor muscles and some intrinsic hand muscles, including the thenar muscles responsible for thumb movements.
Causes of Injury
- Supracondylar fracture of the humerus (common in children).
- Compression at the carpal tunnel (Carpal Tunnel Syndrome).
- Penetrating injuries to the forearm or wrist.
- Lacerations from trauma or surgery.
Clinical Features: Hand of Benediction
When a person with proximal median nerve injury is asked to make a fist:
- The index and middle fingers remain extended,
- While the ring and little fingers flex normally (due to intact ulnar nerve).
This produces a characteristic posture resembling a “Hand of Benediction” or “Preacher’s Hand.”
Why It Happens
The median nerve supplies the flexor digitorum superficialis and the lateral half of the flexor digitorum profundus, which flex the index and middle fingers. When these are paralyzed, the person cannot flex these digits during fist formation.
Other Symptoms
- Weakness in thumb opposition and abduction (difficulty holding objects).
- Sensory loss over the lateral palm and first three fingers.
- Muscle wasting of the thenar eminence, leading to a flattened thumb base.
Location of Lesion
The image indicates a proximal median nerve lesion, meaning injury occurs near or above the elbow.
Treatment
- Splinting and occupational therapy to restore hand function.
- Surgical decompression for carpal tunnel or nerve repair after trauma.
- Physiotherapy for muscle re-education and sensory retraining.
5. Comparison of the Three Hand Lesions
| Type of Lesion | Nerve Involved | Characteristic Deformity | Main Functional Loss | Sensory Loss Area |
|---|---|---|---|---|
| Claw Hand | Ulnar Nerve | Hyperextension of 4th & 5th MCP joints, flexion of IP joints | Weak grip, loss of fine movements | Little finger & half of ring finger |
| Wrist Drop | Radial Nerve | Inability to extend wrist and fingers | Weak wrist and finger extension | Dorsal hand between thumb & index finger |
| Hand of Benediction | Median Nerve | 2nd & 3rd digits extended while making fist | Loss of thumb opposition & index/middle finger flexion | Lateral palm & first 3 fingers |
6. Diagnosis and Investigations
Diagnosis of nerve lesions involves:
- Clinical examination: Muscle strength, reflexes, and sensory tests.
- Tinel’s and Phalen’s tests for nerve compression.
- Nerve conduction studies (NCS) and electromyography (EMG) to localize and assess severity.
- MRI or Ultrasound for structural visualization of nerve entrapment.
7. Treatment Principles
Treatment depends on the type, location, and severity of the nerve lesion. Key approaches include:
-
Conservative Management
- Rest, splinting, and anti-inflammatory therapy.
- Physical and occupational therapy to maintain function.
- Avoiding further compression or trauma.
-
Surgical Management
- Nerve decompression (e.g., for carpal tunnel).
- Nerve repair or grafting after laceration.
- Tendon transfer to restore lost movement.
-
Rehabilitation
- Physiotherapy to regain range of motion and prevent contractures.
- Sensory re-education for touch and position awareness.
- Functional training to regain activities of daily living.
8. Prevention and Prognosis
Prevention
- Proper ergonomics while typing, cycling, or lifting.
- Avoid prolonged elbow flexion or wrist compression.
- Regular stretching and strengthening of forearm muscles.
Prognosis
Early diagnosis and treatment often lead to good recovery. However, severe or long-standing nerve damage can cause permanent muscle weakness and deformity. Rehabilitation and consistent therapy play a vital role in maximizing recovery potential.
Conclusion
Hand nerve lesions are more than just anatomical problems — they profoundly affect a person’s independence, confidence, and daily life.
Whether it is the claw-like posture of an ulnar injury, the drooping wrist from radial nerve palsy, or the preacher’s hand seen in median nerve damage, each condition tells a silent story of lost function and disrupted communication between the brain and the body.
Early recognition, accurate diagnosis, and proper treatment can restore not only movement but also the ability to work, create, and express — reminding us that in medicine, as in life, function truly speaks louder than words...