Muscles involved: Palmar interosseous, dorsal interosseous of the thumb
Recommended for musicians playing the piano, guitar, flute, etc. With the help of the opposite hand, separate the fingers from each other, one by one. An alternative is to place an object like a cylinder or a rubber ball between the fingers and press it using the other hand towards the interdigital spaces of each finger. Some small muscles of the hand, the palmar interosseous for example, respond very well to this alternative.
Although the easiest one to separate may be the thumb (it’s called the opposing finger for a reason), the work should involve the entire hand.
Certain professions and hobbies demand excellent finger mobility, especially in the artistic fields. For example, musicians who play any one of several instruments like piano, guitar, flute, etc., will all benefit from this exercise, which they should practice conscientiously.