The flexor pollicis longus is one of three muscles in the deep compartment of the anterior muscles of the forearm.
The name in Latin translates as the long flexor of the thumb. The muscle is unique to humans, and is either a non-functional or not present in other primates.
Base of the distal phalanx of the thumb
Anterior Interosseus Nerve (from median nerve)
Anterior interosseus artery (ulnar artery -> common interosseus artery -> ant. interosseus artery).