Answer:
The flexor pollicis longus muscle inserts into the distal phalanx of thumb and it originates from anterior radius and interosseous membrane.
Step-by-step explanation:
The flexor pollicis longus muscle is present in the forearm and the hand. This muscle is present only in the humans and therefore, is either absent or is rudimentary in the other primates. This muscle is responsible for flexing the thumb.
This muscle originates at the anterior surface of radius and also from the interosseous membrane of the forearm.
The flexor pollicis longus inserts into the base of distal phalanx of the thumb.