[15], Deep muscles of posterior surface of the forearm. Learning anatomy is a massive undertaking, and we're here to help you pass with flying colours. Grounded on academic literature and research, validated by experts, and trusted by more than 1 million users. Standring, S. (2016). Abductor pollicis longus muscle (Musculus abductor pollicis longus) - Yousun Koh. In one study, the accessory tendon was inserted into the trapezium (41%); proximally on the abductor pollicis brevis (22%) and opponens pollicis brevis (5%); had a double insertion on the trapezium and thenar muscles (15%); or the base of the first metacarpal (1%). Its tendon forms the anterior border of the anatomical snuffbox. Abductor pollicis longus also helps to abduct the hand (radial deviation) at the radiocarpal joint. vittodp. Travelling obliquely down and lateralward, abductor pollicis longus terminates within a tendon, which goes through an indentation on the lateral part of the lower end of the radius, along with the tendon of the extensor pollicis brevis. This action is seen in activities such as bowling and shoveling. This is a triangular space found at the base of the thumb, distal and posterior to the styloid process of radius. The abductor pollicis longus (APL) is a muscle found in the deep layer of the posterior compartment of the forearm.As it descends, it becomes superficial and passes under the extensor retinaculum and through the 1 st extensor compartment of the wrist before attaching distally. The site of origin is located just inferior to the insertion of the anconeus muscle. The tendon of abductor pollicis longus forms the lateral border of the anatomical snuffbox. Abductor pollicis longus tendon then passes beneath the extensor retinaculum. [14] The APL sesamoid is present in all non-human primates, but only in about half of gorillas, and normally absent in humans. Anatomy and human movement: structure and function (6th ed.). [4] The posterior interosseous nerve is derived from spinal segments C7 & C8. These nerves provide the muscle with electrical messages from the brain that tells the muscle to contract (this process is called innervation). Kenhub. precision and power grip. Compared to the wrists of chimpanzees, the human wrist is derived (compared to the Pan-Homo LCA) in having considerably longer muscle moment arms for a range of hand muscles. Abductor pollicis longus originates from the posterior surface of the proximal half of the radius, ulna and intervening interosseous membrane. Kim Bengochea, Regis University, Denver, Author: Some fibers may also insert into surrounding structures; opponens pollicis, abductor pollicis brevis and the fascia of thenar eminence. Abductor pollicis longus - Insertion. [12], In chimpanzees, the APL flexes the thumb rather than extends it like in modern humans. All rights reserved. Ease your learning about the hand muscles using Kenhub's muscle anatomy and reference charts! This article will discuss the anatomy and function of abductor pollicis longus muscle. Netter, F. (2019). [7] Up to seven tendons have been reported in rare cases. Philadelphia, PA: Wolters Kluwer Health/Lippincott, Williams & Wilkins. The abductor pollicis longus lies immediately below the supinator and is sometimes united with it. Just proximal to the wrist, the muscle gives off a narrow tendon. The posterior interosseous nerve and artery course between the abductor pollicis longus and extensor digitorum, passing over abductor pollicis longus’ superficial surface. 2020 More specifically, it produces (mid-) extension and abduction of the thumb at the first metacarpophalangeal joint. Atlas of Human Anatomy (7th ed.). The hand contains a lot of muscles and is filled with complicated anatomy. The dorsal interosseous nerveis a branch of the larger radial nerve, and it consists of nerve fibers from the seventh and eighth cervical nerves (C7 and C8). The abductor pollicis longus descends obliquely and ends in a slim tendon that passes vertically downwards to reach the dorsal surface of the hand. The adductor pollicis is a flat, triangular muscle, lying deep in the thenar compartment. and grab your free ultimate anatomy study guide! Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). In doing so, it traverses the first dorsal (extensor) compartment of the retinacular space. Apart from supinator, all the deep extensor muscles span from the forearm to the hand, crossing the wrist joints and thus being able to act upon them. Derek Moore 0 % Topic. It also assists in extending and rotating the thumb. [6], An accessory abductor pollicis longus (AAPL) tendon is present in more than 80% of people and a separate muscle belly is present in 20% of people. The site of origin is located just inferior to the insertion of the anconeus muscle.From here, the muscle courses inferolaterally towards the radial side of the hand, becoming more superficial as it enters the distal third of the forearm. Blood supply to the abductor pollicis longus muscle comes from the interosseous branches of the ulnar artery; Acting alone or with abductor pollicis brevis, abductor pollicis longus pulls the thumb away from the palm. 2000): Manipulatory Behavior and Tool Use", "Anatomic Study of the Abductor Pollicis Longus: A Source for Grafting Material of the Hand", "Anatomic Landmarks for the First Dorsal Compartment", "A Rare Quadruplicate Arrangement of Abductor Pollicis Longus Tendons — Anatomical and Clinical Relevance", "Functional anatomy of the gibbon forelimb: adaptations to a brachiating lifestyle", "Structure and function of the abductor pollicis longus muscle", "Functional relationship between the abductor pollicis longus and abductor pollicis brevis muscles: an EMG analysis", "Evidence of a false thumb in a fossil carnivore clarifies the evolution of pandas", "The evolutionary history of the hominin hand since the last common ancestor of Pan and Homo", https://en.wikipedia.org/w/index.php?title=Abductor_pollicis_longus_muscle&oldid=984825538, Creative Commons Attribution-ShareAlike License, This page was last edited on 22 October 2020, at 09:55. Register now mel_downton. • Gray's Anatomy (41tst ed.). [8], Multiple APL tendons can be regarded as a functional advantage since injured tendons can be compensated by the healthy ones. Read more. Copyright © The adductor pollicis arises with two heads: the oblique and the transverse head.. This tendon passes through a groove carved on the lateral surface of the distal end of the radius, where it is joined by the tendon of extensor pollicis brevis muscle. Philadelphia, PA: Lippincott Williams & Wilkins. Ventricles, meninges and blood vessels of the brain, Posterior surface of proximal half of radius, ulna and interosseus membrane, Base of metacarpal bone 1, (trapezium bone), Anterior interosseous artery, posterior interosseous artery, The proximal part of the muscle is supplied by the lateral branch of the, The distal part is vascularised by a perforating branch of the. It arises from the lateral part of the dorsal surface of the body of the ulna,[1] below the insertion of the anconeus, from the interosseous membrane, and from the middle third of the dorsal surface of the body of the radius.