Body processes

Wartenberg Reflex – Function, Task & Diseases

Wartenberg reflex

The Wartenberg reflex is a reflex from the group of pathological reflexes. It belongs to the pyramidal tract signs and thus provides indications of a disease of the nervous system .

What is the Wartenberg reflex?

The Wartenberg reflex is also known as the Wartenberg sign . It was named after the American neurologist Robert Wartenberg. Similar to the Gordon finger spread sign and the Trömner reflex , the Wartenberg reflex belongs to the pyramidal tract signs of the upper extremity.

It is positive when flexing fingers two, three, and four strikes against resistance from the thumbs , and occurs almost exclusively with a lesion of the pyramidal tract .

function & task

The pyramidal tract is part of the pyramidal system (PS). In its entirety, the pyramidal system is responsible for voluntary motor skills and fine motor skills. Central motor neurons are located in the primary motor cortex in the brain . Motor neurons are nerve cells that supply nerves to the body’s muscles They are the basis of muscle contractions in active skeletal muscles . The nerve fibers of these central motor neurons run from the cortex through the brainstem and spinal cord to the lower motor neuron. 

The entirety of these motoneurons and their nerve fibers is called the pyramidal tract. In the area of ​​the pyramidal crossing, at the transition from the brain to the spinal cord, more than 80% of the nerve fibers cross to the other side. The functionality of the pyramidal path can therefore be tested with the help of the pyramidal path symbols.

Pyramidal signs are reflexes or involuntary, rhythmic muscle contractions (clonus) that, when they occur in adults, are pathological. In infants, these phenomena are physiological, since the pyramidal tracts are not yet fully developed.

In the Wartenberg sign, the index, middle, and ring fingers are actively flexed against resistance. With a negative Wartenberg sign, nothing else happens next to it. With a positive Wartenberg sign, on the other hand, the thumb bends into the palm of the hand. One speaks here of a pathological joint movement of the thumb.

The Wartenberg sign is performed in side comparison with the other hand. A positive Wartenberg sign indicates a lesion of the pyramidal tract.

Diseases & Ailments

Pyramidal signs often occur when there is unilateral damage to the pyramidal system. The most common cause of such a unilateral lesion is a stroke . A stroke is a brain and central nervous system disorder caused by reduced blood supply to the brain. Stroke is the third most common cause of death in Germany and the most common cause of moderate and severe physical disabilities. In the event of a stroke, the nerve cells suddenly receive too little oxygen . This is usually caused either by a vascular occlusion (ischemic stroke) or an acute cerebral hemorrhage(hemorrhagic insult). As a result of the pyramidal crossing, there is usually paralysis on the opposite side of the body. For example, if the infarction took place in the right hemisphere, a positive Wartenberg sign on the left side can indicate a lesion in the right hemisphere. 

Other symptoms that indicate a stroke are visual disturbances in one or even both eyes, double vision , visual field loss , dizziness , nausea , vomiting , gait disturbances , weakness , severe headache , difficulty swallowing (dysphagia) or disorientation . Complete paralysis occurs only in rare cases . The so-called extrapyramidal control usually persists and can take over some functions.

A positive Wartenberg reflex can also occur in multiple sclerosis . Multiple sclerosis is a chronic disease of the nervous system. The myelin sheaths of the nerve fibers are particularly affected . Many nerve fibers are covered with an insulating layer for faster stimulus transmission. This layer is also known as the myelin sheath or myelin sheath. In multiple sclerosis, numerous foci of inflammation develop in these myelin sheaths , which lead to degeneration of the insulating layer. This is also referred to as multiple demyelination foci. The white matter of the brain and spinal cord is primarily affected, and thus also the pyramidal tract.

However, since nerve inflammation can occur anywhere in the nervous system, multiple sclerosis can cause almost any neurological symptom. At the beginning of the disease, visual and sensory disturbances usually occur. A typical symptom is seeing double vision. Sensitivity disorders such as paresthesia , pain or numbness occur in the legs and hands . If the motor system is affected, there are also signs of paralysis in the extremities. However, the symptoms are not always obvious. Therefore, a positive Wartenberg sign should always suggest multiple sclerosis.

A disease in which a positive Wartenberg reflex can also occur is multiple system atrophy . It is a neurodegenerative disease that progresses rapidly and affects different systems at the same time. The disease usually occurs between the ages of 40 and 60. In addition to the positive pyramidal tract signs, there are mainly extrapyramidal motor symptoms such as tremors or muscle rigidity ( rigor ). Cerebellar symptoms such as nystagmus or unsteadiness in walking and standing can also occur. Swallowing disorders, speech disorders, urinary incontinence and erectile dysfunction are also treatedobserved in affected patients. Those affected also often suffer from depression .

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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.