Flexor Pollicis Brevis   

- Origin:
    - superficial head: distal border of the flexor retinaculum;
    - greater multangular bone tuberosity of the trapezium bone deep head;
    - trapezoid and capitate bones;
- Insertion: base of the proximal phalanx of the thumb;

- Action:
    - flexes proximal phalanx of the thumb; continued action flexes first metacarpal and rotates it medially;
- Synergists:  FPL, adductor pollicis;

- Nerve supply: superficial head: Median, C8,  T1
                        deep head:        Ulnar, C8, T1;

- Discussion:
    - FPB is on volar surface of metacarpal and under abductor brevis;
    - one head of the flexor brevis originates from volar carpla ligament and in the region of the Flexor Carpi Radialis tendon;
    - other originates from trapezium and from capitate tendon that inserts into radial sesamoid & radial tubercle of proximal phalanx;
    - this muscle also attaches to an expansion into the extensor mech. and assists in extending the distal phalanx of the thumb

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, April 10, 2012 3:49 pm