Inverted Reflexes

An inverted tendon reflex refers to the elicitation of the movement opposite to that normally seen when the reflex is elicited.

Inverted supinator reflex
Source: Apte, A. P., Aware, S., Maniar, A., Bharadwaj, S., & Fuse, A. (2020). Functional outcome of Anterior Cervical Discectomy and Fusion with Anterior Cervical Plating Among Patients of Cervical Disc Disease at a Tertiary Health Care Centre. MVP Journal of Medical Sciences, 67–77.

Mechanism of Inverted Reflexes

A lesion which simultaneously affects:

  1. A root or roots: interrupting the local reflex arc, and
  2. The spina cord: damaging the corticospinal tract which supply segments below the arc.

This leads to 2 components:

  1. Absence of the contraction of muscle tapped
  2. Hyperactive response of the muscle subserved by a lower spinal segment

Mechanisms of hyperactive response:

  1. Central mechanism:
    • Babinski/Dejerine theory: reflex irradiation to a lower level by a central mechanism
    • Walshe theory: emergence of an alternative motor response or, as it were, a replacement of one reflex by another
    • Dietrichson/Landau/Clare theory: increase in alpha motoneuron excitability exists in upper motor neuron lesion
  2. Peripheral mechanism:
    • Teasdall/Magladery and Lance/de Gail theory: irradiation of myotatic reflexes is not secondary to intraspinal spread but is due instead to a ‘peripheral’ mechanism attributed to the stimulation of spindles of the muscles involved due to heightened sensitivity of the spindles (Lance, 1965; Lance and de Gail, 1965).

Types of Inverted Reflexes

1. Inverted supinator reflex:

  • Level of pathology: C5/6
  • Positive response: Flexion of fingers and extension of elbow rather than elbow flexion when eliciting the supinator (brachioradialis) jerk.

2. Paradoxical triceps reflex:

  • Level of pathology: C7
  • Positive response: Flexion of elbow rather than extension when eliciting the triceps jerk.

3. Inverted knee jerk:

  • Level of pathology: L2/3/4
  • Positive response: Flexion of knee (hamstring contraction) rather than knee extension when eliciting the knee or quadriceps jerk.


  1. A Dictionary of Neurological Signs By A.J. Larner
  2. Estanol BV, Marin OS. Mechanism of the inverted supinator reflex. A clinical and neurophysiological study. J Neurol Neurosurg Psychiatry. 1976 Sep;39(9):905-8. doi: 10.1136/jnnp.39.9.905. PMID: 1086890; PMCID: PMC492480.

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