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Opponens Pollicis

 



- 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