Wrist Drop Causes, Symptoms & Diagnosis

Wrist drop, also known as radial nerve palsy, is a medical condition that results in the inability to extend or lift the hand at the wrist joint. This condition is often caused by nerve damage, most commonly affecting the radial nerve that controls the muscles responsible for wrist and finger extension. Common causes of wrist drop include trauma or injury to the arm, nerve compression, or certain medical conditions such as diabetes.

1.      Relevant anatomy:

The relevant anatomy involved in wrist drop includes:

• Radial Nerve: The radial nerve originates from the brachial plexus in the neck and travels down the arm to innervate the muscles that control wrist and finger extension. It can be injured or compressed at various points along its course, leading to wrist drop.
• Muscles: The muscles affected in wrist drop are primarily those responsible for wrist extension. These muscles include the extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, and extensor digitorum.
• Nerve Pathway: The radial nerve sends signals from the brain to the muscles in the forearm, allowing for wrist and finger extension. Any disruption along this nerve pathway can result in weakness or paralysis of these muscles, causing the wrist to drop.

Common causes of wrist drop include trauma or injury to the arm, compression of the nerve (e.g., due to prolonged pressure on the nerve), or certain medical conditions like radial nerve entrapment, brachial plexus injury, or nerve-related disorders.

2.      Wrist Drop Causes

• Wrist drop, also known as radial nerve palsy, can be caused by various factors, such as:
• Trauma or injury to the wrist, forearm, or upper arm, leading to nerve compression or damage.
• Nerve entrapment, where the radial nerve gets compressed by surrounding structures.
• Prolonged pressure on the nerve, which can occur during prolonged use of crutches or improperly using a tight cast.
• Certain medical conditions, such as nerve disorders, diabetes, or autoimmune diseases.
• Infection or inflammation affecting the radial nerve.
• Repetitive motions or overuse of the wrist and forearm muscles.

3.      Wrist Drop Symptoms

Wrist drop is a condition where there is weakness or paralysis of the muscles that control wrist extension. Common signs and symptoms include:

• Inability to extend or lift the wrist.
• Weakness in the hand and fingers, making it difficult to grip objects.
• Loss of sensation or tingling in the hand and fingers.
• Difficulty in performing activities that require wrist movement, such as writing or using utensils.
• The hand may appear to hang limply when attempting to lift it.

4.      Wrist Drop Diagnosis

Diagnosing radial nerve palsy typically involves a medical evaluation by a healthcare professional. They may conduct physical examinations, review medical history, and perform nerve conduction studies or electromyography to confirm the diagnosis. Imaging tests like X-rays or MRI scans may be used to rule out other possible causes.

5.      Special tests of Wrist Drop

For wrist drop, special tests may include:

• Elbow Flexion Test: The patient is asked to fully flex their elbow, and if the wrist does not automatically extend, it suggests weakness in the wrist extensor muscles.
• Wrist Extensor Test: The patient is asked to extend their wrist against resistance to check for weakness or limited range of motion.
• Grip Strength Test: Assessing the strength of the patient’s grip can help identify any weakness in the wrist extensor muscles.
• Tinel’s Sign: A tapping test over the median nerve in the wrist can help identify if there’s any nerve compression contributing to wrist drop.
• Phalen’s Test: The patient flexes both wrists to 90 degrees and holds them together for about one minute. If symptoms worsen, it could indicate carpal tunnel syndrome or other nerve-related issues.
• Electromyography (EMG) and Nerve Conduction Studies (NCS): These tests can help evaluate the function of the nerves and muscles in the affected wrist.

6.      Wrist Drop Differential diagnosis:

• Radial nerve compression or injury: The radial nerve runs down the arm and controls wrist extension. Compression or damage to this nerve can result in wrist drop.
• Radial tunnel syndrome: Similar to carpal tunnel syndrome, but affecting the radial nerve, causing wrist drop and pain in the forearm.
• Cervical radiculopathy: Nerve compression in the neck region can lead to wrist drop due to impaired nerve signals.
• Muscular dystrophy: Certain forms of muscular dystrophy can weaken the muscles controlling wrist movement, leading to wrist drop.
• Stroke: A stroke affecting the brain or brainstem may cause weakness or paralysis, including wrist drop.
• Peripheral neuropathy: Damage to peripheral nerves, often due to conditions like diabetes, can cause wrist drops.
• Trauma: Direct injury to the wrist or arm can result in nerve damage and wrist drop.

7.      Wrist Drop Treatment:

Wrist drops can have various underlying causes, so treatment depends on the specific reason for the condition. Common causes include nerve compression, nerve injury, or certain medical conditions like radiculopathy or peripheral neuropathy.

• Immobilization: In some cases, wearing a splint or brace can help stabilize the wrist and prevent further damage while allowing it to heal.
• Physical therapy: Exercises and stretches prescribed by a physical therapist can improve the strength, flexibility, and function of the wrist and hand.
• Medication: If inflammation or pain is present, nonsteroidal anti-inflammatory drugs (NSAIDs) may be recommended to alleviate symptoms.
• Nerve gliding exercises: These exercises can help to promote nerve mobility and reduce compression.
• Nerve decompression surgery: If compression of the nerve is the cause of the wrist drop, surgery may be necessary to release the pressure on the affected nerve.
• Treatment of underlying medical conditions: If wrist drop is a result of an underlying medical condition like diabetes or multiple sclerosis, managing the condition is essential to improve symptoms.

8.      Physiotherapy for Wrist Drop:

Physiotherapy plays a crucial role in the rehabilitation of individuals with wrist drops. A well-structured physiotherapy program can help regain wrist functionality, strengthen the affected muscles, and improve overall hand dexterity. Here, we outline some effective physiotherapy techniques to aid in your recovery journey:

1. Passive Range of Motion (PROM) Exercises

Passive range of motion exercises involves gently moving the wrist joint through its full range of motion. These exercises are especially beneficial in the early stages of wrist drop when active movements might not be possible. PROM exercises help maintain joint flexibility and prevent stiffness.

• Active Range of Motion (AROM) Exercises

As the wrist starts to regain some strength, active range of motion exercises are introduced. These exercises involve the individual moving the wrist without any external assistance. Gradually increasing the range of motion will help improve muscle function and promote better hand movement.

• Strengthening Exercises

Strengthening exercises are a crucial component of wrist drop physiotherapy. These exercises focus on targeting the specific muscles that control wrist and finger extension. By gradually increasing resistance and intensity, the affected muscles can regain their strength and support functional movements.

• Neuromuscular Re-education

Neuromuscular re-education techniques help reestablish the connection between the brain and the affected muscles. Therapists use various sensory cues and exercises to enhance muscle activation and improve overall coordination.

• Constraint-Induced Movement Therapy (CIMT)

CIMT is a specialized technique that involves restricting the movement of the unaffected hand, forcing the affected hand to perform tasks and exercises. This approach encourages the brain to rewire and focus on the recovery of the affected hand.

• Electrical Stimulation

Electrical stimulation is often used in conjunction with other physiotherapy techniques. This treatment involves the use of electrical currents to stimulate the affected muscles, promoting muscle contraction and strengthening.

9.      Exercises for wrist drop

Here are ten exercises that can help with wrist drop:

• Wrist Curls: Sit or stand with your forearm supported and palm facing upward. Hold a light weight (dumbbell or household object) and curl your wrist upward, then lower it slowly.
• Wrist Extensions: Similar to wrist curls, but with the palm facing downward. Lift the weight by extending your wrist upward, then lower it slowly.
• Ball Squeeze: Hold a soft ball in your hand and squeeze it as tightly as you can for a few seconds. Repeat several times.
• Finger Flexor Stretch: Gently pull back on your fingers with your opposite hand to stretch the muscles on the palm side of your wrist.
• Finger Extensor Stretch: Extend your fingers and thumb, then gently pull them backward to stretch the muscles on the back of your wrist.
• Wrist Rotations: Hold your arm out straight with your palm facing downward. Rotate your wrist in circles, both clockwise and counterclockwise.
• Wrist Flexor Stretch: Hold your arm straight out with your palm facing upward. Use your opposite hand to bend your wrist downward gently.
• Wrist Extension Stretch: Hold your arm straight out with your palm facing downward. Use your opposite hand to bend your wrist upward gently.
• Hand Gripper Exercises: Use a hand gripper to improve grip strength and wrist stability.
• Towel Twist: Place a small towel flat on a table and grip one end with your affected hand. Twist the towel to wring it out.

10. Preventive Measures and Lifestyle modification:

While physiotherapy plays a vital role in radial nerve rehabilitation, adopting certain preventive measures and lifestyle modifications can aid in maintaining nerve health and preventing injuries. Here are some practical tips:

1. Maintain Good Posture

Maintaining proper posture during daily activities and work tasks can minimize strain on the nerves and muscles of the upper limb.

• Ergonomic Workspace

Ensure that your workspace is ergonomically designed to reduce strain on the arms and wrists while typing or using a computer.

• Avoid Repetitive Movements

Limit repetitive movements that can lead to overuse injuries, and take regular breaks during activities that involve continuous arm use.

• Warm-up and Stretching

Prior to engaging in any physical activity or sports, perform warm-up exercises and gentle stretching to prepare the muscles and nerves.

• Nutrition and Hydration

Maintain a balanced diet and stay hydrated to support nerve health and overall well-being.