Inverted Supinator Test

Original Editor - Vidya Acharya
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Purpose[edit | edit source]

The Inverted Supinator Test is used for identifying a lesion at the C5-C6 spinal cord level. The Inverted Supinator Reflex is a test that was introduced into clinical medicine by Babinski (1910). [1]There are two primary components of this abnormal reflex:

  • An absence of contraction of the brachioradialis muscle when the styloid process of the radius is tapped, and
  • A hyperactive response of the finger flexor muscles; a response that is subserved by a lower spinal cord segment (C8).

Technique[edit | edit source]

The patient is in a seated position.The therapist places the patient's slightly pronated forearm on his forearm, to assure the full relaxation of the patient's forearm. The therapist hen applies a series of quick strikes near the styloid process of the radius at the attachment of the brachioradialis tendon. [2]

  • A positive test (abnormal response) involves either finger flexion and/or elbow extension [3]
  • A normal response includes wrist pronation and/or elbow flexion.[3]

Evidence[edit | edit source]

  • The test has a demonstrated sensitivity of 61% and a specificity of 78% [3]
  • Research aimed at producing a cluster of predictive clinical test findings for a sample of a patient using a clinical diagnosis as the reference standard for cervical myelopathy found that selected combinations of clinical findings:

(1) gait deviation;

(2) +Hoffmann’s test;

(3) inverted supinator sign;

(4) +Babinski test; and

(5) age >45 years

are good predictors of cervical myelopathy and were effective in ruling out and ruling in cervical spine myelopathy.[4]

  • The presence of 3 or 4 findings out of 5 displayed high specificity for ruling in cervical myelopathy, and when only 1 of the 5 clinical findings was present, there was high sensitivity for ruling out cervical myelopathy.
  • Another study assessing the presence of the inverted radial reflex and its clinical relevance in asymptomatic patients (n=277; age range:16-78) for 6 months found incidence of the inverted supinator reflex was 27.6% (75/271) and the reflex was present bilaterally in 39% (29/75) suggesting that an isolated inverted supinator reflex, in the absence of other clinical findings, is not a reliable sign of cervical myelopathy; however, it must be interpreted with caution in the older patient.[5]
  • A study assessing the interrater reliability, diagnostic accuracy of clinical neurological tests (used singularly and in clusters), and subjective findings associated with a MRI-confirmed diagnosis (using signal intensity changes) of cervical spine myelopathy demonstrated significant diagnostic accuracy for the inverted supinator sign along with Babinski; and also demonstrated moderate inter-rater agreement for inverted supinator sign (L = 0.52; 95% CI: 0.26-0.78).[2]

[6]

References[edit | edit source]

  1. Estanol BV, Marin OS. Mechanism of the inverted supinator reflex. A clinical and neurophysiological study. Journal of Neurology, Neurosurgery & Psychiatry. 1976 Sep 1;39(9):905-8.
  2. 2.0 2.1 Cook C, Roman M, Stewart KM, Leithe LG, Isaacs R. Reliability and diagnostic accuracy of clinical special tests for myelopathy in patients seen for cervical dysfunction. journal of orthopaedic & sports physical therapy. 2009 Mar;39(3):172-8.
  3. 3.0 3.1 3.2 Neck and Arm Pain Syndromes E-Book: Evidence-informed Screening, Diagnosis. Cesar Fernandez de las Penas, Joshua Cleland, Peter A. Huijbregts
  4. Cook C, Brown C, Isaacs R, Roman M, Davis S, Richardson W. Clustered clinical findings for diagnosis of cervical spine myelopathy. Journal of Manual & Manipulative Therapy. 2010 Dec 1;18(4):175-80.
  5. Kiely P, Baker JF, O'hEireamhoin S, Butler JS, Ahmed M, Lui DF, Devitt B, Walsh A, Poynton AR, Synnott KA. The evaluation of the inverted supinator reflex in asymptomatic patients. Spine. 2010 Apr 20;35(9):955-7.
  6. Physiotutors Inverted Supinator Sign | Upper Motor Neuron Lesion. Available from https://www.youtube.com/watch?v=_H5Pv8istcI&vl=es. Accessed on 25/2/21