Where and why is the nerve compressed?
The radial nerve comes from the brachial plexus, bends around the humerus along a spiral groove and descends to the forearm, giving branches to the extensor muscles. In the groove, it is pressed against the bone and is almost not protected by soft tissues, so prolonged pressure from the outside easily disrupts its function. The nerve sheath suffers earlier than the axial cylinder itself: if the pressure was short-lived, conductivity is completely restored. In case of a fracture or injury, a more severe option is possible - damage to the fibers, and then recovery is slow.
- Compression in the spiral groove of the humerus
- Sleeping with your arm under your head or on the back of a chair
- Humerus fracture and callus
- Compression by tourniquet, cuff, crutch
- Injection into the nerve area
- Compression of the posterior interosseous branch in the elbow area
Symptoms
The main symptom is the inability to straighten the hand and fingers at the main joints: the hand hangs down, the fingers are bent. Because of this, the grip sharply weakens, although the flexors themselves work. The back surface of the forearm, hand and first three fingers goes numb, especially the skin between the thumb and index finger. There is usually no or moderate pain. If the nerve is damaged higher up, the extension of the forearm at the elbow also suffers. The doctor determines the level of damage by the set of missing functions.
- Drooping hand, inability to straighten it
- Weakness in finger extension and thumb abduction
- Decreased grip strength
- Numbness of the back of the hand and forearm
- Tingling and burning during recovery
- With a high lesion - weakness of extension at the elbow
Causes and risk factors
The classic situation is deep sleep in an uncomfortable position, when the hand is pinched for a long time. This often happens after drinking alcohol or taking sleeping pills, when the person does not change position and does not feel numb. The second large group of causes are injuries: fractures of the middle third of the shoulder, dislocations, incised wounds. Less commonly, the nerve is compressed by a tumor, hematoma, scars, and also suffers from systemic diseases. Increased vulnerability of nerves occurs with diabetes, vitamin B12 deficiency, and alcohol addiction.
- Sleeping with a pinched hand
- Fracture or dislocation in the shoulder area
- Prolonged use of crutches
- Tight tourniquet or plaster
- Diabetes mellitus and vitamin B12 deficiency
- Chronic alcohol intoxication
Diagnostics
The diagnosis is mainly clinical: the doctor checks the strength of extension of the hand and fingers, sensitivity in the innervation zones and determines the level of damage. Electroneuromyography shows exactly where conduction is disrupted and how much the fibers are damaged, and also helps predict recovery time. A study 2–3 weeks after the onset of symptoms is informative. Ultrasound of the nerve reveals compression, thickening, scarring, and rupture. An X-ray of the humerus is needed in case of injury. In case of bilateral lesions, a common cause is additionally sought.
- Neurological examination with assessment of strength and sensitivity
- Electroneuromyography
- Ultrasound of the radial nerve along
- X-ray of the humerus in case of injury
- Blood glucose, vitamin B12 as indicated
- MRI for suspected mass formation
Treatment and recovery
If the nerve is only compressed, treatment is conservative. A key role is played by an orthosis that holds the hand in an extended position: it prevents muscle overstretching and the formation of contracture. Perform passive and active exercises daily to maintain joint mobility. Treatment is complemented by physiotherapy, electrical muscle stimulation and massage. Your doctor may prescribe B vitamins and medications that improve nerve recovery. If there is no improvement after 3-4 months or there is initially a nerve rupture, surgery is discussed. The entire program is selected by the doctor.
- Orthosis that holds the hand in extension
- Daily therapeutic exercises
- Electrical stimulation of extensor muscles
- Massage and physiotherapy
- B vitamins as prescribed
- Surgical treatment for rupture or lack of dynamics