 He is credited with coining the word "camptodactyly" to describe a flexion deformity of the finger(s) at the proximal interphalangeal joint (1906).With neurologist Joseph Grasset (1849–1918), his name is associated with the "Landouzy-Grasset Law".This law states that in lesions concerning one hemisphere of the brain, a patient will turn his head to the side of affected muscles if there is spasticity, and to the side of the cerebral lesion if there is paralysis.