Paralysis of opponens muscle leads to loss of following function of thumb:
Opponens pollicis muscle attaches to the trapezium, flexor retinaculum, and first metacarpal. It pulls the thumb medially and forward across the palm so that the palmar surface of the tip of the thumb may come into contact with the palmar surface of the tips of the other fingers. It is an impoant muscle and enables the thumb to form a claw in the pincerlike action used for picking up objects. Paralysis of opponens muscle leads to loss of pincer action of thumb. Ref: Snell's anatomy, 7th edition, Page 542-543.
Flexion
Extension
Pinching
Abduction