Variations of the flexor digitorum superficialis of the small finger.

Normal functional variations of the flexor digitorum superficialis were clinically determined by use of the standard and modified superficialis flexion tests in 50 normal subjects. Forty hands of 20 cadavers were dissected to correlate the anatomic variations with the clinical findings. A flexor digitorum superficialis-independent pattern was found 58% of the time. A flexor digitorum superficialis-common pattern was found 21% of the time. A flexor digitorum superficialis-absent pattern was found 21% of the time. The right and left hands were asymmetric 26% of the time. All cadaver hands had a flexor digitorum superficialis tendon present in the palm and finger. The variability in flexor digitorum superficialis function may be explained by interconnections between the flexor digitorum superficialis of the small finger and either the flexor digitorum superficialis of the ring finger or the flexor digitorum profundus of the small finger.