The flexor mechanism of the hand refers to the complex system of tendons, muscles, ligaments, and other structures responsible for flexing or bending the fingers, thumb, and wrist.

The flexor mechanism of the hand refers to the complex system of tendons, muscles, ligaments, and other structures responsible for flexing or bending the fingers, thumb, and wrist.

1. Flexor mechanism of hand By: Yashaaswini.n

2. Introduction Muscles of finger and thumb have proximal attachment above wrist (complete this or correct this) . 2 main muscle contribute finger flexion: a. Flexor digitorum superficialis b. Flexor digitorum profundus 7/28/2021 2

3. Flexor digitorum superficialis & Flexor digitorum profundus Flexes PIP & MCP More torque than FDP Crosses few joint and superficial to FDP @ MCP Greater Moment Arm for MCP joint Flexes MCP, PIP and DIP joint (actively) Finger flexion of FDS &FDP works together 7/28/2021 3 (S pecify about what muscle you are saying)

4. ORIGIN & INSERTION OF FDS & FDP 7/28/2021 4

5. Relation btw FDS & FDP FDS travel superficial to FDP and at the level of PIP, FDS (splits or slips?) slips (CAMPER’S CHIASMA) and FDS attach base of middle phalanx FDS & FDP dependent on wrist position for optimal LENGTH-TENSION relationship Counter balancing external torque at the wrist by extensor carpi radialis brevis and sometimes by extensor digitorum communics (check the spelling) . 7/28/2021 5

6. STRUCTURE OF FLEXOR MECHANISM Flexor Retinaculum Ulnar & Radial bursa Deep Tendon Sheath Transverse metacarpal ligament Annular & Cruciate ligament FDS & FDP 7/28/2021 6

7. Optimal function of FDS & FDP depends on: Stabilization by wrist musculature Intact flexor gliding mechanism. About the infection. 7/28/2021 7 Flexor Retinacula Bursae Digital tendon sheath

8. Gliding mechanism Fibrous Retinacular structure tether long flexor tendon to hand. Bursae & tendon sheath facilitate friction free excursion. FDS & FDP crosses wrist pass beneath proximal to flexor Retinaculam through carpal tunnel then bursa. FPL passes through carpal tunnel with FDS & FDP then radial bursa. 7/28/2021 8

9. ANNULAR & CRUCIATE PULLEY A1 : head of MC A2 : volar midshaft of proximal phalanx A3: distal most part of proximal phalanx A4: centrally on middle phalanx A5: base of distal phalanx. C1: btw A2 & A3 C2: btw A3 & A4 C3: btw A4 & A5 7/28/2021 9

10. PULLEY 7/28/2021 10

11. FUNCTION OF ANNULAR PULLEY To keep flexor tendon close to bone. Allow minimum amount of bowstring & migration Volarly from joint axes. Enhances tendon excursion efficiency & work efficiency of long tendon. 7/28/2021 11

12. ZONES OF HAND Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 7/28/2021 12

13. 7/28/2021 13

14. PALMAR APONEUROSIS PULLEY Proximal to A1 pulley one more pulley resembles like A1 pulley. 7/28/2021 14