Flexor Digitorium Superficialis (FDS) testing: The FDS functions independently. To test the FDS, the adjacent fingers are held in an extended position while the patient is asked to flex the tested finger. This method allows for evaluation of the FDS as the affected finger is observed for PIP flexion. Point of interest 20% of patients have an absent FDS in the small finger so patients may have limited or no PIPJ flexion during testing of the small finger. Exert taken from EHT’s fantastic NEW course: FLEXOR TENDONS; GET A GRIP