Muscle Name: opponens pollicis

AKA:  

Abbreviation:  

Spinal Nerve Roots:
    C8
    T1

Brachial Plexus Trunks:
    lower trunk

Brachial Plexus Cords:
    medial cord

Named Nerves:
    median nerve

Proximal Attachment: Trapezium and transverse carpal ligament.

Distal Attachment:  Metacarpal bone of the thumb on its radial side

Action: Flexion of the thumb's metacarpal at the first carpometacarpal joint, which aids in opposition of the thumb.

Needle Insertion: In the supinated hand the needle is iserted in the lateral aspect of the thenar eminence, approximately on finger-breadth distal to the first metacarpal bone.

Activation for EMG:  Have the patient oppose the thumb to the little finger.

Pitfalls:  If the needle is inserted too medially it will be in the abductor pollicis brevis.

Notes: