Finger agnosia

Finger agnosia, first defined in 1924 by Josef Gerstmann, is the loss in the ability “to distinguish, name, or recognize the fingers”, not only with the patient’s own fingers, but also the fingers of others, and drawing and other representations of fingers. It is one of a tetrad of symptoms in Gerstmann syndrome, although it is also possible for finger agnosia to exist on its own without any other disorders. Usually, lesions to the left angular gyrus and posterior parietal areas can lead to finger agnosia.