Thoracic flexion, a rapid forward flexion at the waist, can elicit a circumferential electrical sensation in some patients with multiple sclerosis. The clinical and radiographic features of this phenomenon are described here. This symptom is typically a sensory band around the T6-T7 dermatomes and is usually associated with recent thoracic cord lesions. It is clinically independent of cervical pathology and Lhermitte's sign. Similar to the vertical radiation of symptoms upon neck flexion due to cervical cord lesions, this sign may help localize MS plaques to the thoracic cord, even when thoracic MRI is negative.
Keywords: Hug; Lhermitte; multiple sclerosis; spinal cord; thoracic.