Leonardo da Vinci suffered from 'claw hand,' not post-stroke paralysis, study finds

Famed artist and inventor Leonardo da Vinci suffered from a crippled right hand late in life, usually attributed to a stroke.
 
In a new paper in the Journal of the Royal Society of Medicine, two Italian researchers argue that Leonardo more likely suffered from a condition colloquially known as "claw hand." They base their argument on analysis of a 16th-century portrait of an elderly Leonardo, Ars Technica reports.
 
The quintessential Renaissance man is known to have been the illegitimate son of a Florentine notary named Piero Fruosino di Antonio da Vinci. (His mother, Caterina, was a peasant). Much of what is known about Leonardo's life comes from the writing of the 16th-century painter and historian Giorgio Vasari, in Lives of the Most Excellent Painters, Sculptors, and Architects. 

Historians have also studied Leonardo's drawings and his use of "mirror writing" in his journals, concluding he was almost certainly predominantly left-handed, although he was ambidextrous to some extent.