Jendrassik Maneuver

The Jendrassik maneuver is a simple yet effective technique used by clinicians to enhance muscle reflexes that may be difficult to elicit during a physical examination. Named after the Hungarian neurologist Ernő Jendrassik, this maneuver is widely used in both upper and lower extremity reflex testing.

What is the Jendrassik Maneuver?

The Jendrassik maneuver involves asking the patient to perform a voluntary isometric contraction away from the muscle being tested, which can amplify the reflex response. This is particularly useful when reflexes are subtle, inhibited, or when patient relaxation is challenging.

How to Perform the Jendrassik Maneuver

1. Upper Extremity Reflexes

To enhance upper limb reflexes (e.g., biceps or triceps reflexes):

• Ask the patient to cross their ankles while sitting or lying down.
• Instruct them to isometrically attempt to abduct the legs, creating voluntary tension in the lower body.
• The upper extremity reflex is then tested as usual.

2. Lower Extremity Reflexes

To enhance lower limb reflexes (e.g., patellar or Achilles reflexes):

• Ask the patient to interlock their fingers.
• Instruct them to isometrically attempt to pull the elbows apart, generating voluntary contraction in the upper body.
• The lower extremity reflex is then tested in the standard manner.

See Also: Deep Tendon Reflex Testing

Why Use the Jendrassik Maneuver?

• Amplifies subtle reflexes: Helpful when reflexes are difficult to detect.
• Reduces patient inhibition: Voluntary contraction distracts the nervous system, making reflexes easier to elicit.
• Simple and non-invasive: Can be performed quickly at bedside without special equipment.

Clinical Applications

The Jendrassik maneuver is commonly used in:

• Neurological examinations
• Orthopedic assessments
• Physical therapy evaluations

It is especially useful for patients with anxiety, fatigue, or reduced muscle tone, where reflexes may appear diminished.

Key Takeaways

The Jendrassik maneuver is a reliable, non-invasive, and easy-to-perform technique that enhances the accuracy of reflex testing in both upper and lower extremities. Incorporating this maneuver into routine neurological exams can improve diagnostic precision and patient care.

References & More

1. Jendrassik maneuver – Wikipedia
2. Dowman R, Wolpaw JR. Jendrassik maneuver facilitates soleus H-reflex without change in average soleus motoneuron pool membrane potential. Exp Neurol. 1988 Aug;101(2):288-302. doi: 10.1016/0014-4886(88)90012-x. PMID: 3396646. Pubmed
3. Ertuglu LA, Karacan I, Yilmaz G, Türker KS. Standardization of the Jendrassik maneuver in Achilles tendon tap reflex. Clin Neurophysiol Pract. 2017 Nov 16;3:1-5.