Compared with flexor digitorum profundus (FDP) tendon injury, the isolated rupture of flexor digitorum superficialis (FDS) tendon in a finger is a rare report in the literature. The pathogenesis is still unclear if we consider only tendon rupture without congenital anomalies or other diseases. The diagnosis is clinical, but it can be confirmed by ecography or magnetic resonance imaging (MRI). We report the case of a flexor superficialis (FS) tendon closed rupture of the ring finger of right hand in a 57-year-old patient. The diagnosis was confirmed by MRI. No surgical repair was used, given the limited clinical repercussions.