- Origin:
flexor retinaculum and tubercle of trapezium bone;
- Insertion:
radial side of entire length of first metacarpal bone;
- Action:
flexes & abducts first metacarpal w/ medial rotation at hand;
- Synergists: abductor pollicis,
adductor pollicis;
- Nerve:
Median,
C8 >
T1;
- Discussion:
- opponens pollicis winds around a part of the 1st metacarpal;
- this muscle lies under the abductor brevis and acts primarily as
internal rotator and stabilizer of the 1st metacarpal;
- Exam:
- abductor pollicis & opponens pollicis pronate or oppose thumb & can
be evaluated by asking pt to touch thumb & small fingertips
together so that the nails are parallel;
- can also be tested by asking pt to place dorsum of hand flat on
table & raise thumb up straight to form 90 deg angle with the palm;
- one must palpate the thenar muscle and ensure that it is contracting;
