Brachioradialis: Difference between revisions

| Origin = [[Lateral supracondylar ridge]] of the [[humerus]] and the orbicular ligament of the radius

| Nerve = [[Radial nerve]] ([[C5-C8]] & [[Thoracic spinal nerve 1|T1]])

| Action = [[Flexion]] of [[elbow]], supination and supinationpronation of the radioulnar joint to 90°

The '''brachioradialis''' is a [[muscle]] of the [[forearm]] that flexes the forearm at the [[elbow]].<ref name=":0">{{Citation|last=Johnson|first=G. R.|title=1 - Developments in joint replacement technology*Note: This chapter is an updated version of Chapter 1 from the first edition of Joint replacement technology edited by P. A. Revell and published by Woodhead Publishing, 2008.*|date=2014-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780857098412500011|work=Joint Replacement Technology|pages=3–30|editor-last=Revell|editor-first=P. A.|publisher=Woodhead Publishing|language=en|doi=10.1533/9780857098474.1.3|isbn=978-0-85709-841-2|access-date=2020-12-12}}</ref><ref name=":1">{{Citation|last=Day|first=Judd S.|title=12 - The Clinical Performance of UHMWPE in Elbow Replacements|date=2016-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780323354011000120|work=UHMWPE Biomaterials Handbook (Third Edition)|pages=179–196|editor-last=Kurtz|editor-first=Steven M.|place=Oxford|publisher=William Andrew Publishing|language=en|doi=10.1016/b978-0-323-35401-1.00012-0|isbn=978-0-323-35401-1|access-date=2020-12-12}}</ref> It is also capable of both [[pronation]] and [[supination]], depending on the position of the forearm.<ref name=":1" /> It is attached to the distal [[radial styloid process|styloid process]] of the [[radius (bone)|radius]] by way of the brachioradialis tendon, and to the [[lateral supracondylar ridge]] of the [[humerus]].

The brachioradialis is a superficial, [[Anatomical terms of muscle#Form|fusiform]] muscle on the [[Anatomical terms of location#Medial and lateral|lateral]] side of the forearm. thatIt attachesoriginates [[Anatomical terms of location#Proximal and distal|proximally]] on the [[lateral supracondylar ridge]] of the [[humerus]]. andIt inserts distally on the [[radius (bone)|radius]], closeat tothe base of its [[Radial styloid process|its styloid process]].<ref>{{Cite journal|last1=Freehafer|first1=Alvin A.|last2=Hunter Peckham|first2=P.|last3=Keith|first3=Michael W.|last4=Mendelson|first4=Laurel S.|date=1988-01-01|title=The brachioradialis: Anatomy, properties, and value for tendon transfer in the tetraplegic|url=https://dx.doi.org/10.1016%2F0363-5023%2888%2990210-9|journal=The Journal of Hand Surgery|language=en|volume=13|issue=1|pages=99–104|doi=10.1016/0363-5023(88)90210-9|pmid=3351238|issn=0363-5023}}</ref> Near the elbow, it forms the lateral limit of the [[cubital fossa]], or elbow pit.<ref>{{cite book|last1=Moore|first1=KL.|last2=Dalley|first2=AF.|last3=Agur|first3=AM.|date=2013|title=Clinically Oriented Anatomy, 7th ed.|publisher=Lippincott Williams & Wilkins |pages=751–752|isbn=978-1-4511-8447-1}}</ref>

===InnervationNerve supply===

Despite the bulk of the muscle body being visible from the anterior aspect of the forearm, the brachioradialis is a posterior compartment muscle and consequently is innervated by the [[radial nerve]].<ref>{{Cite journal |last=Catala |first=Martin |last2=Kubis |first2=Nathalie |date=2013 |title=Gross anatomy and development of the peripheral nervous system |url=https://pubmed.ncbi.nlm.nih.gov/23931773/ |journal=Handbook of Clinical Neurology |volume=115 |pages=29–41 |doi=10.1016/B978-0-444-52902-2.00003-5 |issn=0072-9752 |pmid=23931773}}</ref> Of the muscles that receive innervation from the radial nerve, it is one of only four that receive input directly from the radial nerve. The other three are the [[triceps brachii muscle|triceps]], [[anconeus muscle|anconeus]], and [[extensor carpi radialis longus]]. (All other posterior compartment muscles that receive radial innervation are supplied by the [[deep branch of the radial nerve]].)<ref>{{citationCitation |last=Palastanga |first=Nigel |title=Preface needed|date=March1994 2014|work=Anatomy and Human Movement |pages=viii |url=http://dx.doi.org/10.1016/b978-0-7506-0970-8.50004-6 |access-date=2024-08-22 |publisher=Elsevier |isbn=978-0-7506-0970-8 |last2=Field |first2=Derek |last3=Soames |first3=Roger}}</ref>

The brachioradialis flexes the forearm at the elbow.<ref name=":0" /><ref name=":1" /> When the forearm is pronated, the brachioradialis tends to supinate as it flexes.<ref name=":1" /> In a supinated position, it tends to pronate as it flexes.<ref name=":1" /> This also assists the [[biceps brachii]].<ref name=":1" />

The brachioradialis is a stronger elbow flexor when the forearm is in a midposition between [[supination]] and [[Anatomical terms of motion|pronation]] at the [[Proximal radioulnar articulation|radioulnar joint]]. When pronated, the brachioradialis is more active during elbow flexion since the biceps brachii is in a mechanical disadvantage.

With the insertion of the muscle so far from the fulcrum of the elbow, the brachioradialis does not generate as much joint [[torque]] as the [[brachialis]] or the biceps. It is effective mainly when those muscles have already partially flexed at the elbow. The brachioradialis flexes the forearm at the elbow, especially when quick movement is required and when a weight is lifted during slow flexion of the forearm.

{{Gallery|width=150|height=150|lines=2File:Gray207.png|Left humerus. Anterior view.

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