Final answer:
The extensor pollicis longus is a muscle in the deep posterior compartment of the forearm, responsible for extending the thumb and contributing to thumb abduction. It is innervated by the posterior interosseous nerve and receives its blood supply from the posterior interosseous artery.
Step-by-step explanation:
Extensor Pollicis Longus Muscle Anatomy
The extensor pollicis longus is one of the muscles located in the deep posterior compartment of the forearm. This muscle plays a significant role in hand function. It originates from the ulna and the interosseous membrane and inserts on the base of the distal phalanx of the thumb.
The main actions of the extensor pollicis longus are to extend the thumb at the carpometacarpal and interphalangeal joints and to help in thumb abduction when the wrist is in a neutral position.
The innervation of the muscle is provided by the posterior interosseous nerve, a branch of the radial nerve. Its blood supply comes from the posterior interosseous artery, which accompanies the nerve of the same name. Together, they facilitate the muscle's various movements including the fine motor skills required for precise actions such as writing and typing.