Vincenzo Neri (1880-1960) and his sign to detect leg weakness due to corticospinal tract injury

The Italian neurologist Vincenzo Neri (1880-1960), a pupil of Joseph Babinski (1857-1932), greatly contributed to refining the semiotics of neurological examination and was a pioneer in medical cinematography. In 1909, Neri proposed a sign to diagnose leg paresis due to a pyramidal tract lesion. According to Neri, if a patient standing with the legs apart and the arms crossed on the chest bends the trunk of the pelvis, when the trunk has almost reached the horizontal line, the leg on the paralyzed side flexes, whereas the unaffected leg remains extended. This sign reflects a spinal hyperfunctioning emerging after a pyramidal lesion, and should be interpreted as a part of a triple flexion reflex. Beyond the acute stage, it could reflect an unusual pattern of flexor spasticity involving the lower limb due to corticospinal tract injury. The sign described by Neri retains its validity in identifying this organic leg weakness due to pyramidal lesions, particularly when it is mild or in its early stages.