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- See:
       - Intrinsic Plus Finger
       - Lumbical Plus Finger
       - Phalangeal Injury

- Discussion:
    - lumbical plus finger should be distinguished from intrinsic plus finger;

- Clinical Presentation:
    - gripping medium-sized objects such as hammer handle is done primarily through IP joint flexion because handle effectively blocks MP joint from achieving full flexion;
    - pts w/ intrinsic tightness will become symptomatic when repetitively using this grip configuration against resistance;

- Technique:
    - intrinsic tightness is demonstrated by comparing passive PIP joint flexion w/ MP joint held in extension and then flexion;
    - test for intrinsic tightness is performed by passively holding pt's MCP joints extended & either actively or passively flexing PIP joints;
    - since intrinsics are put on stretch by MCP extension, if they are tight, IP joints will have limited flexion;
    - if PIP joint flexion is restricted when MP joint is held in extension but not when MP joint is held in flexion, pt has positive intrinsic tightness test;
    - attempts at active digital extension characterized by hyperextension of MP joint w/ simultaneous flexion of the PIP joint;
    - when MP joint are held in flexion, active extension of IP joint is normal