In this study we aimed to systematically investigate and map localization of the individual finger fascicles within the flexor digitorum superficialis (FDS) and the flexor digitorum profundus (FDP) muscles.Using B-mode ultrasonographic assessments, the right forearms of ten healthy participants (five males and five females) were examined during active and passive finger movements.A topographical map indicating clear core areas of fascicle activation within the FDS and FDP muscles was created. Borders that could, to some degree, define individual differences were also indicated.Our findings offer a detailed image of fascicle distributions within the FDS and FDP muscles. Various challenges, such as managing individual muscular profiles or the existence of the palmaris longus muscle, are discussed and should always be taken into consideration. The current map can serve as a general orientation for future measurements or injection therapies.