Troemner Reflex: Function, Tasks, Role & Diseases

The Trömner reflex is a muscle reflex (increased finger flexor reflex) that can also occur in almost any healthy person. It is considered a sign of autonomic hyperexcitability and, in strong or unilateral expression, also a pyramidal tract sign. Unilateral absence indicates, for example, a radicular lesion (sensorimotor pain and deficits in the region of a spinal nerve root).

What is the Trömner reflex?

The Trömner reflex is visible when you strike the palmar side of the phalanx of the middle finger. The Trömner reflex is what is known as a pathologic reflex. A pathological reflex is an involuntary reaction of the body that does not normally occur. The Trömner reflex is visible when you strike the palmar side of the middle finger phalanx. The palmar side is the flexor side of the hand. The blow then causes a reflex flexion of the fingers, under pathological conditions. This movement is also called flexion.

Function and task

The Trömner reflex is a muscle intrinsic reflex. In muscle intrinsic reflexes, the receiving and the succeeding organs are located in the same muscle. Normally, attenuation or absence of the intrinsic reflexes is an indication of disease. A different intensity on both sides can also indicate damage. However, the Trömner reflex is a pathological reflex. It does not occur in healthy people. If it is observed, this suggests a disease. A reflex hammer is used to perform the Trömner reflex. This can be used to test muscle, tendon and skin reflexes. Most reflex hammers have two different sized rubber inserts on their heads. For reflex testing on the hand, the smaller rubber insert is used. This is used to strike the flexor side of the middle finger phalanx. In a healthy person, nothing happens as a result. In the case of nervous system disorders, however, the fingers flex reflexively. This is called a positive Trömner reflex. The reflexes are always tested in a side-by-side comparison. This is the only way to assess the reflex response. This reflex response is usually documented in the categories normal, diminished, attenuated, increased or absent. There are also clinical scale systems that allow a more precise classification. The best known scales are the nine-level Mayo Clinic Scale (MCS) and the National Institute of Neurological Disorders and Stroke scale (NINDS scale). However, they are rarely used in everyday practice because the assignment to the individual values varies too much between different examiners. Thus, the scales have only limited reliability. The Trömner reflex is connected via the vertebral segments C7 and C8. The effector nerves are the median arm nerve and the ulnar nerve. Effector muscles are the finger flexors, called the Mm. flexores digitorum.

Diseases and complaints

A mild positive Trömner reflex may occur with autonomic hyperexcitability. This hyperexcitability is also called vegetative dystonia. In this case, there is impaired conduction of excitation in the autonomic nervous system. The autonomic nervous system regulates blood pressure, pulse, respiratory rate, digestion and to some extent also muscle tension. Vegetative dystonia is often the result of stress, mental strain and hectic activity. In addition to increased reflexes or pathological reflexes, nervousness, restlessness, irritability, insomnia, dizziness, cramps, constipation, liverbile complaints or a loss of libido may also occur. When severe and unilateral, the Trömner reflex is considered an unsafe pyramidal tract sign. Pyramidal tract signs are neurological symptoms, reflexes, or involuntary rhythmic contractions of muscle groups or muscles that are pathologic in adults and occur especially when there is damage to what is called the pyramidal tract. The pyramidal tract is a nerve pathway in the spinal cord and brain that plays an important role in controlling voluntary motor function. The Trömner reflex is one of the pyramidal tract signs of the upper extremity. Other pyramidal tract signs of the upper extremity include the Gordon finger spread sign or the Wartenberg reflex. The pyramidal tract can be damaged within the brain by stroke. In a stroke, there is a lack of oxygen to the brain. As a result, the tissue in the brain is severely damaged. The most common cause of stroke is vascular occlusion.This is also referred to as an ischemic infarction. Cerebral hemorrhage can also cause an infarction. This is also called a hemorrhagic infarction. Typical symptoms are hemiplegia, speech disorders, visual disturbances, impaired consciousness or even unconsciousness, confusion, disorientation, nausea or sudden headaches. Positive pyramidal tract signs are also frequently found in multiple sclerosis. Multiple sclerosis is a chronic disease associated with inflammation of the myelin sheaths in the nervous system. The myelin sheaths serve to electrically insulate nerve fibers in the central nervous system (CNS). The cause of the disease is unclear. Demyelination occurs as a result of autoimmune processes. In particular, the white matter of the brain and spinal cord is affected. Multiple sclerosis is the chameleon of neurological diseases. Due to the wide distribution of demyelination foci, it can cause almost any neurological symptom. Typical symptoms include visual disturbances, numbness, pain, muscle spasms, slurred speech, nystagmus (eye tremors), dysphagia, vertigo, incoordination, and an intention tremor. Disorders of autonomic centers or pathways may also result in bladder and bowel dysfunction. Often, affected individuals also suffer from increased fatigue and depressive moods. The Trömner reflex can also be positive in the case of incipient amyotrophic lateral sclerosis (ALS). ALS is a non-curable disease of the nervous system. There is progressive damage to the nerve cells responsible for muscle movement (motoneurons). The motor nerve cells of the cerebral cortex and the anterior horn cells of the spinal cord may be affected. The cause of the disease is unclear. The clinical picture of amyotrophic lateral sclerosis is highly variable. There are functional limitations of the muscles, spastic paralysis, a slowed gait, speech and swallowing disorders, lockjaw, muscle spasms, and twitching of the tongue muscles.