- Discussion:
-
adductor pollicis consists of 2 parts, one of which is transverse & other oblique;
- transverse head attaches to the volar crest of the 3rd metacarpal;
- oblique head attaches to ligaments around capitate, trapezium, and covering of the
FCR;
- heads insert separately or together into ulnar tubercle at base of proximal phalanx and partially into the
lateral band mechanism of extensor tendon;
- Anatomy:
- origin:
- transverse head: distal 2/3 of palmar surface of 3rd metacarpal bone;
- oblique head: capitate bone, base of 2nd and 3rd metacarpal bone;
- insertion:
- two heads converge to insert onto ulnar sesamoid, lateral tubercle of proximal phalanx and the volar plate;
- action:
- adduction and aids in flexion of the thumb at MP joint:
- supplies 50% of the adduction force to the first metacarpal;
- synergists:
-
FPB,
FPL &
opponens pollicis;
-
FPL supplies 25% of thumb adduction;
- nerve supply: ulnar,
C8 >
T1;
- Nerve Injury:
- Froment's Sign:
- have pt forcibly hold piece of paper between thumb & radial side of index proximal phalanx;
- when ADP is weak or nonfunctioning, the thumb IP joint flexes w/ this maneuver;
- compare the two hands at the same time;
- Tendon Transfers to Restore Adduction:
- operative procedures to be considered are:
-
adductor pollicis substitution by
FDS of long finger passed thru interosseous membrane (base of second & third
interosseous space), over and under
ECU as distal pulley;
- beneath
EDC, & into adductor insertion, anchoring tendon into bone;
- interosseous and
lumbricals
of ring finger & little fingers, substituted by the
FDS of ring finger;
Restoration of pinch in ulnar nerve palsy by transfer of split extensor digiti minimi and
Extensor Indicis.
The origin and innervation of the adductor pollicis muscle.
