The deep forearm extensors consist of the extensor pollicis brevis, supinator, abductor pollicis longus, extensor pollicis longus and extensor indicis muscles. It sits directly medial to abductor pollicis longus and posterolateral to extensor pollicis longus muscle. Derek Moore 0 % Topic. Description: Origin: Posterior surface of the radius distal to the abductor pollicis and the adjacent interosseous membrane Insertion: Dorsolateral surface on the base of the proximal phalanx of the thumb Actions: … The extensor pollicis brevis muscle is located on the dorsal side of the forearm. From here, the muscle runs downwards towards the wrist, ending in a cord-like tendon proximally to the wrist. After passing under the retinaculum, the tendon runs laterally to insert onto the dorsal surface of the base of the proximal phalanx of thumb. In this study we studied variations in the tendons of the EPB in the first extensor compartment and its site of insertion. Netter, F. (2014). Grounded on academic literature and research, validated by experts, and trusted by more than 1 million users. Extensor pollicis longus (EPL) is a long muscle located at the deep layer with extensor pollicis brevis, abductor pollicis longus, extensor indicis, and supinator muscle in the posterior compartment of the forearm. O: Posterior surface of the radius and ... EXT of proximal phalanx of thumb @ MP, EXT first MC of thumb at CMC joint, AB thumb (weakly), and Helps with RD. Edinburgh: Churchill Livingstone. Kenhub. This movement is important in the anatomy of the grip, as it enables letting go of an object. Extensor pollicis brevis muscle: want to learn more about it? Insertion :- 0. Insertion Edinburgh: Elsevier Churchill Livingstone. Base of 3rd metacarpal (dorsal surface). Origin: Originates from the posterior surface of the radius and interosseous membrane. It also extends the thumb in the carpometacarpal joint of the thumb. 1st Carpometacarpal and metacarpophalangeal joint: Thumb extension. Extensor Pollicis Brevis. Extensor pollicis brevis lies radial to extensor pollicis longus. The extensor pollicis brevis originates from the lower third of the posterior surface of the radius and the interosseous membrane. Article by Custom Pilates and Yoga | Pain Relief from Simple Exercises. Arteries of the back of the forearm and hand. Actions – Extension of the wrist. Nerve supply :-Deep branch of radial nerve . Extensor pollicis brevis lies radial to extensor pollicis longus. Origin: Posterior surface of middle 1/3 of ulna and interosseous membrane Insertion: Base of distal phalanx of thumb Action: Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints Innervation: Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve Arterial Supply: Posterior interosseous artery Origin: Posterior surfaces of radius and interosseous membrane: Insertion: Base of proximal phalanx of thumb: Action: Extends proximal phalanx of thumb at metacarpophalangeal joint: Innervation: Insertion :- Derek Moore 0 % Topic. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Posterior aspect of base of proximal phalanx of thumb. Abduction of the wrist. Abductor Pollicis Longus (APL) Insertion: base of the 1st metacarpal; Action: extension of the 1st metacarpal and helps with abduction; Innervation: posterior interosseous branch of the radial nerve; Extensor Pollicis Brevis (EPB) Reviewer: Artery supply : Posterior interosseous artery. Palastanga, N., & Soames, R. (2012). Insertion (distal attachment) a. It originates from the flexor retinaculum and the tubercles of the scaphoid and trapezium bones. The main action of this muscle is to extend the thumb on the carpometacarpal and metacarpophalangeal joints, together with its long counterpart, extensor pollicis longus muscle. Extensor pollicis brevis - Insertion. This is an important clinical point since it is the most common spot for the palpation of the radial pulse. The extensor pollicis brevis muscle has its origin on the dorsal surface of the radius below the abductor pollicis longus muscle. Cael, C. (2010). Its tendon runs just lateral to the extensor pollicis longus tendon to insert at the base of the first phalanx of the thumb on the dorsal aspect. Origin of Extensor Pollicis Brevis Posterior surfaces of radius and interosseous membrane Insertion of Extensor Pollicis Brevis Base of proximal phalanx of thumb The extensor pollicis longus constitutes the posterior border of the region of the hand known as the anatomical snuff box, which is the triangular indentation in the radial-dorsal aspect. Philadelphia, PA: Saunders. Clinically Oriented Anatomy (7th ed.). Extensor pollicis brevis is innervated by posterior interosseous nerve which is a continuation of a deep branch of radial nerve (root value C7 and C8). Attachments of the Extensor Carpi Radialis Brevis Muscle: Origin and Insertion. The tendon of extensor pollicis longus and the styloid process of radius make the medial and proximal borders of this space, respectively. The mucous sheaths of the tendons on the back of the wrist. Ventricles, meninges and blood vessels of the brain, Posterior surface of distal third of radius and interosseus membrane, Posterior aspect of base of proximal phalanx of thumb, Carpometacarpal and metacarpophalangeal joint 1: Thumb extension, Posterior interosseous artery, anterior interosseous artery. Extensor Pollicis Longus. (Extensor pollicis brevis labeled at upper left. Deep muscles. [1]. Review Topic. ), Posterior surface of the forearm. Function . Origin: Distal and dorsal aspect of radius, distal to the origin of abductor pollicis longus; interosseous membrane. Extensor pollicis brevis (EPB) is one of the muscles of the deep layer of the posterior compartment of the forearm, insertion into the base of the proximal phalynx of the thumb. The extensor pollicis brevis arises from the ulna distal to the abductor pollicis longus, from the interosseous membrane, and from the dorsal surface of the radius.. Its direction is similar to that of the abductor pollicis longus, its tendon passing the same groove on the lateral side of the lower end of the radius, to be inserted into the base of the first phalanx of the thumb. Start studying Muscle of arm origin and insertion. Your extensor pollicis longus and extensor pollicis brevis muscles help move your thumbs. The extensor pollicis brevis muscle has its origin on the dorsal surface of the radius below the abductor pollicis longus muscle. aspect. It is connected with the extensor pollicis … Kim Bengochea, Regis University, Denver, Author: Learn about these important muscles and how to keep them healthy. Learning the muscles of the forearm is tough! ... Extensor Pollicis Brevis. This article incorporates text in the public domain from page 455 of the 20th edition of Gray's Anatomy (1918), Front of right upper extremity.