What reflexes are there on the arm?
You can trigger different reflexes on your arm. The starting position is the patient in the supine position, who places his arms loosely on the groin. As a rule, the following four are tested:
- Biceps tendon reflex: in the biceps tendon reflex, one of the examiner’s fingers is placed on the biceps tendon in the crook of the elbow and then it is struck.
This causes the forearm to bend.
- Brachioradialis-/Radiuspersiostreflex: The Brachioradialis reflex is triggered by tapping the inner forearm near the wrists. This results in a slight flexion of the forearm.
- Triceps tendon reflex: for the triceps tendon reflex, the examiner strikes the said tendon on the outer elbow, stretching the forearm.
- Trömner reflex: the Trömmer reflex is triggered when the hand is hanging relaxed. The examiner flicks from the front against the fingertips. This causes the hand to close slightly.
What reflexes do the hairs have?
The hair is also subject to reflexes. Everyone knows the phenomenon of the so-called “goose bumps”. This is ultimately a reflex which leads to the hair straightening.
The whole thing is evolutionary: Our ancestors were much hairier than we are. When it was cold or in danger, the hair cells straightened up reflexively, so that the coat was puffed up. On the one hand, this resulted in the inclusion of air and thus a layer of insulation against the cold, and on the other hand, the coat looked much more threatening. This reflex has remained with us until today, even though its function is probably negligible by now.
How can reflexes be tested?
The examination or testing of the reflexes is part of the physical examination and the neurological examination. This examination tests whether the reflexes can be triggered to the same side to the physiological extent and depending on the reflex, or whether pathological reflexes are present. Depending on the reflex to be examined, the so-called reflex status is examined with a reflex hammer or other neurological aids, such as a brush, a pointed object or even the examiner’s hand.
When testing autonomic reflexes, a light blow with the reflex hammer is applied to the tendon of a muscle (e.g. patellar tendon reflex), causing the muscle to contract. Whenever possible, a reflex is always examined in a side-by-side comparison in order to better assess the reflex response. The reflex response is assessed as “normal”, “diminished”, “increased” or “absent”.
If a doctor wants to test the reflexes of his patient, the means of choice is the so-called reflex hammer. This is a device which, with a practiced technique, makes it possible to tap very precisely and with the same force on a specific area (usually a tendon). The hammer is usually made of metal, but can also be made of plastic and has rubber ends. There are many different models, the most common being the “Trömner” hammer, which has two different sized ends: one for adults and one for children. It is characterized by its medium-length handle and characteristically shaped grip.
