Achilles tendon reflex

The Achilles tendon reflex (ASR, also Triceps surae reflex ) is a reflex that belongs to the group of self-reflexes .

The reflex is triggered by a light tap on the Achilles tendon . The afferent leg of the reflex arch is the tibial nerve , which directs the stimulus to the spinal cord , more precisely to its cross part (sacral section, S1 and S2). Here the switch to the efferent thigh takes place , which also triggers a reflex contraction of the triceps surae muscle via the tibial nerve . This causes the ankle to be stretched (plantar flexion of the foot).

In the case of functional disorders of the thyroid gland , this reflex can be triggered particularly vigorously and can provide a diagnostic indication here. Severe damage to the spinal cord can widen the reflex triggering zone.

The absence of the reflex is an indication of damage to the anterior cruciate area of ​​the spinal cord, such as occur, for example, in trauma , poliomyelitis and neurosyphilis . Furthermore, a missing Achilles tendon reflex can occur if the corresponding nerve roots are damaged , for example as a result of a herniated disc .

Individual evidence

1. ↑ ^{a b} Willibald Pschyrembel : Clinical Dictionary , 266th, updated edition, de Gruyter, Berlin 2014, ISBN 978-3-11-033997-0, keyword reflexes
2. ↑ Entry on Achilles tendon reflex in Flexikon , a wiki from DocCheck
3. ↑ Manual for anamnesis and basic physical examination

Web links

• anvil
• Educational film at the University of Mainz

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !