The term median palsy is shorthand for paralysis of the median nerve. This nerve is one of the three main nerves of the arm. In median nerve palsy, flexion of the hand and fingers and thumb function are limited.
What is median nerve palsy?
Median palsy occurs when the median nerve is damaged at some point so that muscles that depend on it no longer receive nerve impulses. The nature and extent of the paralysis depends on the level of its course at which the nerve is damaged. To understand median nerve palsy, it is important to have a rough understanding of the anatomy of the nerve. The median nerve (the “middle nerve”) arises in the axilla from the brachial plexus and runs in a groove medial to the biceps brachii muscle (aka “biceps”) to the elbow. There it enters the front of the forearm between the two heads of the pronator teres muscle and innervates the majority of the flexor muscles here. Together with the tendons of these flexor muscles, the median nerve passes through the carpal tunnel to the hand. In the palm, it branches into sensory end branches and motor branches for the thumb muscles. A rough distinction is made between proximal (near the trunk) median nerve palsy with lesion at the elbow and distal (far from the trunk) median nerve palsy, in which the nerve is damaged at the wrist.
Causes
The most common cause of median nerve palsy is damage from chronic pressure in the carpal tunnel (known as carpal tunnel syndrome). The carpal tunnel is a canal formed by the carpal bones and covered by ligamentous structures. In some people, the carpal tunnel is naturally narrow. If additional pathological space is created, e.g. by tendonitis, the median nerve is chronically compressed. In addition to permanent compression, external force can cause median nerve palsy. Proximal median nerve palsies are often caused by bone fractures or dislocations of the elbow joint. Distal median palsies may be due to cuts to the wrist or fractures of the carpal bones.
Typical symptoms and signs
- Paralysis of the fingers and thumb
- Movement restrictions of the fingers
- Sensory disturbances
Diagnosis and course
Median nerve palsy can usually be diagnosed on the basis of characteristic motor and sensory deficits. In proximal median nerve palsy, an attempted fist closure results in a “swear hand”: only the ring finger and little finger can still be flexed. The “bottle sign” is positive, i.e. a bottle can no longer be grasped properly due to the failure of the thumb muscles. Pronation (inward rotation) of the hand is only incompletely successful. Numbness occurs on the skin of the inside of the hand from the thumb to half of the ring finger. In distal medianus paralysis, the long hand flexors on the forearm still function, so that no swear hand develops. The “bottle sign” is also positive in this case. The fingertips of the index and middle fingers are numb. In addition to the comprehensive neurological examination, a medical history helps with the diagnosis: clues are provided by previous injuries to the arm or a known carpal tunnel syndrome. Apparently, the diagnosis of median palsy can be supported by measuring electrical muscle activity (electromyography).
Complications
Median palsy primarily results in various disturbances of sensibility or paralysis that occur primarily in the fingers and hand. The thumb is also affected by medianus paralysis in most cases. The fingers can only be moved to a limited extent, so that the patient experiences considerable restrictions in everyday life. Certain activities or work can no longer be carried out easily due to the medianus paralysis, so that the quality of life is significantly reduced. Various sensory disturbances also occur, which continue to impair everyday life. The further course of the disease usually also depends on its cause. In most cases, however, no particular complications occur if the injury is not particularly severe. Life expectancy is also not usually limited or reduced by median palsy. Treatment for this paralysis is usually not necessary. In most cases, the symptoms disappear again on their own over time.Only in rare cases are interventions necessary to alleviate the symptoms. In this case, there are likewise no further complications.
When should one go to the doctor?
If complaints of the musculoskeletal system arise, this is a sign of an existing health irregularity. In median palsy, there are limitations in mobility in the areas of the arms and hands. If the affected person can no longer move the arms as usual, he or she needs a doctor. The impairments can occur starting from the shoulder along the arm to the fingers and require medical attention. If the existing symptoms increase in intensity or extent, a visit to the doctor should be made immediately. If there is a loss of the usual physical performance level or irritability, a check-up visit to a doctor is advisable. If the grasping functions can no longer be performed, a medical clarification of the complaints is necessary. As soon as everyday hand movements can no longer be performed, the affected person requires medical care. In a comprehensive medical examination and various tests, the cause of the present malfunctions must be determined so that a diagnosis can be made. If there is a perceptual disorder on the skin of the arm or hands, a doctor is also needed. If there is an irregularity due to touch, irritation of sensitivity, sensory disturbances, tingling on the skin, or numbness, a consultation with a physician should be made.
Treatment and therapy
Treatment of median nerve palsy depends on the cause of damage. Paralysis caused by pressure damage often resolves on its own. If the nerve is severed in a fracture or cut, surgical reconstruction may be attempted. If median nerve palsy results from compression in the carpal tunnel, either conservative therapy (e.g., medication and/ or special paramedic techniques) or surgery is performed, depending on the severity. The goal of surgery is to relieve pressure permanently, for example by opening the entire carpal tunnel or by splitting the tendon. Physical therapy is usually required for follow-up treatment.
Outlook and prognosis
In most cases, patients with median nerve palsy receive a favorable prognosis. Often, because of the self-healing powers of the organism, there is an automatic regression of symptoms until recovery ultimately occurs. Within a few weeks or months the disease is healed. Especially in the case of pressure damage, minor injuries or a strong physical stress of the organism, a regeneration of the nerve activity occurs after a short time. The paralyses are temporary in nature and regress completely. In the future, however, changes should be made in the way of life so that the functional activity of the nerve fibers does not receive irreparable damage. If complaints and health irregularities occur again in the course of life, the prognosis is also favorable for the causes mentioned. In the case of fractures, surgical intervention takes place in a large number of cases. This is associated with risks, but is usually completed in a routine procedure without further disturbances. Overall, median nerve palsy can often be cured by the administration of medications as well as self-help measures. In addition, physiotherapeutic exercises are used to support the healing process and prevent secondary diseases. The affected person can independently contribute something to his improvement of the situation by applying the learned physiotherapeutic training sessions outside the sessions.
Prevention
There is no prevention that can be done for traumatic median nerve palsy. For carpal tunnel syndrome, however, there are modifiable risk factors. People at risk include those who have lost a lot of weight but have not strengthened their muscles much and therefore have flabby connective tissue. Patients with kidney damage or diabetes mellitus also have a higher risk because of the danger of tissue swelling. Initial symptoms of carpal tunnel syndrome are paraesthesia and pain in the palm of the thumb, particularly at night or after mechanical stress on the wrist. Such signs should be taken seriously and evaluated by a physician in order to treat any nerve compression before complete median nerve paralysis develops.
Aftercare
Median nerve palsy is usually associated with a variety of symptoms, most of which can all have a very negative impact on the affected person’s quality of life. Therefore, aftercare focuses on counteracting further worsening of the symptoms. With the help of physiotherapy, the damaged fingers are strengthened muscularly. This is because those affected have to cope with restrictions in movement in their daily lives. Many sufferers are therefore dependent on the help and support of friends and their own family in order to still be able to cope with everyday life. The fingers themselves can no longer be moved properly. Sensory disturbances also occur in the fingers or even in the hand. Touch or temperature can no longer be correctly assessed, which can also lead to discomfort in the daily life of the affected person. The disease itself can be treated well in many cases. It does not have a negative effect on the life expectancy of the affected person and does not usually reduce it.
What you can do yourself
The actions that can be taken for median palsy depend on the cause and severity of the damage. Mild paralysis, for example, caused by a bruise or sprain on the arm, usually goes away on its own. In the case of severe injuries, surgery is required. Beforehand, an examination plan must be drawn up together with the doctor, in which the control examinations and other details are recorded. Shortly before the operation, the affected person should no longer put any strain on the muscle and otherwise adhere to the instructions of the doctor in charge. Recovery can then be supported by the typical aftercare measures, i.e. rest and cooling, but also by light stretching exercises. In general, daily physiotherapy should be performed with a medianus paralysis so that the paralysis completely recedes as quickly as possible. If motor replacement surgery is performed, the donor muscle must be specifically strengthened, for example, by physiotherapy or by massages and aids. Physiotherapeutic exercises are usually started after four to five weeks in the case of replacement surgery. What other measures the affected person can take to promote healing can only be answered by the specialist in charge.
