Extensor plantar response elicited by neck extension
Dr. Bruno Estañol1, Dr. José Luis Mendizábal‑Méndez2, Dr. Guillermo Delgado‑García3,4..
1 Laboratorio de Neurofisiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición, México City, México.
2 Departamento de Neurología, Instituto Mexicano del Seguro Social, Torreon, México.
3 Centro de Investigación y Desarrollo en Ciencias de la Salud, Universidad Autónoma de Nuevo León, Monterrey, México.
4 Department of Clinical Neurosciences, University of Calgary, Foothills Medical Centre, 1403 29 St NW, Calgary, AB T2N 2T9, Canada.
Originally Published / september 16, 2021 / https://doi.org/10.1007/s13760-021-01803-1
Introduction
Dear Prof Patrick Cras,
A while ago, it was reported in the Journal that cervical flexion consistently elicits a unilateral extensor plantar response [1]. In that report, a 74-year-old lady with multiple brain infarcts and uremic encephalopathy was described. The author astutely recognized that the Babinski’s reflex could be elicited with stimulation far beyond the S1 dermatome and into the thighs, abdomen, and chest. However, according to the classical theory, a nociceptive cutaneous stimulation is needed to elicit this pathological reflex [2]. Strictly speaking, cervical flexion and extension are not nociceptive stimuli, and they are more akin to the way we usually use to evoke the Lhermitte’s sign and its variants, which are subjective in nature and not accompanied by motor phenomena. Our patient was a 32-year-old previously healthy Hispanic lady who was diagnosed with a right cervical anterolateral intramedullary lesion (21 × 10 mm) (Fig. 1). When the patient was examined in the sitting position with her head in the natural position, she did not have Babinski’s reflex nor asymmetric myotatic reflexes. When the patient extended her neck, she experienced a hot sensation over the left posterior side of her trunk and, approximately 20 s later, she had right hallux extension (Fig. 2) followed by abduction..
