The musculus abductor pollicis longus, commonly referred to as the abductor pollicis longus (APL), is a muscle located in the forearm region of the human body. It is situated on the back or posterior side of the forearm, extending from the posterior surface of the ulna (one of the two long bones in the forearm) and reaching towards the base of the thumb.
The APL primarily functions as an abductor, meaning it plays a key role in moving the thumb away from the palm of the hand and towards the side, allowing for the hand to perform actions such as thumb extension and opposition. This muscle is activated during various daily activities that involve the use of the thumb, such as writing, holding objects, or gripping tools. Additionally, it is particularly important in upper limb movements that require precision and strength, such as manipulating small objects or performing fine motor skills.
The musculus abductor pollicis longus is innervated by the posterior interosseous nerve, a branch of the radial nerve. It receives its blood supply from multiple sources, including branches of the radial artery. Its name, abductor pollicis longus, is derived from Latin terms: "abductor" meaning to move away from the body, "pollicis" referring to the thumb, and "longus" indicating its relatively long length compared to other forearm muscles.
Understanding the anatomy and function of the musculus abductor pollicis longus is essential in diagnosing and treating conditions related to the forearm and thumb, as it plays a significant role in the overall movement and dexterity of the human hand.
