The Elbow & Radioulnar Joints • Most upper extremity movements involve the elbow & radioulnar joints • Usually grouped together due to close Chapter 6 anatomical relationship The Elbow and Radioulnar Joints • Elbow joint movements may be clearly distinguished from those of the radioulnar joints Manual of Structural Kinesiology • Radioulnar joint movements may be R.T. Floyd, EdD, ATC, CSCS distinguished from those of the wrist © 2007 McGraw-Hill Higher Education. All rights reserved. 6-1 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-2 Bones Bones • Ulna is much larger • Scapula, humerus, & ulna serve as proximally than radius proximal attachments for muscles that • Radius is much larger pronate & supinate the radioulnar joints distally than ulna • Distal attachments of radioulnar joint • Scapula & humerus serve as muscles are located on radius proximal attachments for muscles that flex & extend • Bony landmarks the elbow – medial condyloid ridge • Ulna & radius serve as distal – olecranon process attachments for these same – coranoid process muscles – radial tuberosity © 2007 McGraw-Hill Higher Education. All rights reserved. 6-3 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-4 Bones Joints • Key bony landmarks • Ginglymus or hinge-type joint for wrist & hand • Allows only flexion & extension muscles • 2 interrelated joints – medial epicondyle – humeroulnar joint – lateral epicondyle – radiohumeral joints – lateral supracondylar ridge © 2007 McGraw-Hill Higher Education. All rights reserved. 6-5 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-6 1 Joints Joints • Elbow motions • As elbow flexes 20 degrees – primarily involve movement between or more, its bony stability is articular surfaces of humerus & ulna unlocked, allowing for more – specifically humeral trochlear fitting into side-to-side laxity ulna trochlear notch • Stability in flexion is more – radial head has a relatively small amount dependent on the lateral of contact with capitulum of humerus (radial collateral ligament) – As elbow reaches full extension, olecranon & the medial or (ulnar process is received by olecranon fossa collateral ligament) • increased joint stability when fully extended © 2007 McGraw-Hill Higher Education. All rights reserved. 6-7 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-8 Joints Joints • Ulnar collateral ligament • Radial collateral is critical in providing medial support to ligament provides lateral prevent elbow from stability & is rarely abducting when injured stressed in physical • Annular ligament activity provides a sling effect – Many contact sports & around radial head for throwing activities place stress on medial aspect stability of joint, resulting in injury © 2007 McGraw-Hill Higher Education. All rights reserved. 6-9 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-10 Joints Joints • Elbow moves from 0 degrees of extension • Radioulnar joint to 145 to 150 degrees of flexion – Trochoid or pivot-type joint – Radial head rotates around at proximal ulna – Distal radius rotates around distal ulna – Annular ligament maintains radial head in its joint From Seeley RR, Stephens TD, Tate P: Anatomy & physiology , ed 7, New York, 2006, McGraw-Hill; Shier D, Butler J, Lewis R: hole’s human anatomy & physiology , ed 9, New York, 2002, McGraw-Hill. © 2007 McGraw-Hill Higher Education. All rights reserved. 6-11 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-12 2 Joints Joints • Radioulnar joint • Radioulnar joint – Supinate 80 to 90 degrees from neutral – Joint between shafts of radius & ulna held – Pronate 70 to 90 degrees from neutral tightly together between proximal & distal articulations by an interosseus membrane (syndesmosis) • substantial rotary motion between the bones © 2007 McGraw-Hill Higher Education. All rights reserved. 6-13 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-14 Joints Joints • Synergy between glenohumeral, elbow, & • Synergy between glenohumeral, elbow, & radioulnar joint muscles radioulnar joint muscles – As the radioulnar joint goes through its ROM, – Conversely, when loosening a tight screw with glenohumeral & elbow muscles contract to pronation, we tend to internally rotate & extend the stabilize or assist in the effectiveness of elbow & glenohumeral joints, respectfully movement at the radioulnar joints – we depend on both the agonists and antagonists – Ex. when tightening a screw with a screwdriver in the surrounding joints to assist in an appropriate which involves radioulnar supination, we tend to amount of stabilization & assistance with the externally rotate & flex the glenohumeral & elbow required task joints, respectfully © 2007 McGraw-Hill Higher Education. All rights reserved. 6-15 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-16 Movements Movements • Flexion • Pronation – internal rotary movement – movement of forearm to of radius on ulna that shoulder by bending the results in hand moving elbow to decrease its angle from palm-up to palm- down position • Extension • Supination – movement of forearm away – external rotary movement from shoulder by of radius on ulna that straightening the elbow to results in hand moving from palm-down to palm- increase its angle up position © 2007 McGraw-Hill Higher Education. All rights reserved. 6-17 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-18 3 Muscles Muscles • Elbow flexors • Radioulnar pronators – Biceps brachii – Pronator teres – Brachialis – Pronator quadratus – Brachioradialis – Brachioradialis – Weak assistance from Pronator teres • Radioulnar supinators • Elbow extensor – Biceps brachii – Triceps brachii – Supinator muscle – Anconeus provides assistance – Brachioradialis © 2007 McGraw-Hill Higher Education. All rights reserved. 6-19 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-20 Muscles Muscles • “Tennis elbow" - common problem usually • Anterior involving extensor digitorum muscle near its origin on lateral epicondyle – Primarily flexion & pronation – known lateral epicondylitis – associated with gripping & lifting activities • Biceps brachii • Medial epicondylitis • Brachialis – somewhat less common • Brachioradialis – known as golfer's elbow • Pronator teres – associated with medial wrist flexor & pronator • Pronator quadratus group near their origin on medial epicondyle – Both conditions involve muscles which cross elbow but act primarily on wrist & hand © 2007 McGraw-Hill Higher Education. All rights reserved. 6-21 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-22 Muscles Nerves • All elbow & radioulnar joints muscles are innervated • Posterior from median, musculotaneous, & radial nerves of – Primarily brachial plexus extension & supination • Triceps brachii • Anconeus • Supinator © 2007 McGraw-Hill Higher Education. All rights reserved. 6-23 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-24 4 Nerves Nerves • Radial nerve - • Median nerve - derived from originates from C5, C6, C6 & C7 C7, & C8 – Pronator teres – Triceps brachii – Pronator quadratus (anterior – Brachioradialis interosseus nerve) – Supinator (posterior – Sensation to palmar aspect of interosseous nerve) hand & first three phalanges, – Anconeus palmar aspect of radial side of – Sensation to fourth finger, dorsal aspect of posterolateral arm, index & long fingers forearm, & hand © 2007 McGraw-Hill Higher Education. All rights reserved. 6-25 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-26 Nerves Biceps Brachii Muscle Flexion of elbow • Musculotaneous nerve - Supination of branches from C5 & C6 forearm – Biceps brachii Weak flexion of – Brachialis shoulder joint Weak abduction of shoulder joint when externally rotated © 2007 McGraw-Hill Higher Education. All rights reserved. 6-27 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-28 Brachialis Muscle Brachioradialis Muscle True Flexion of elbow flexion Pronation from supinated of elbow position to neutral Supination from pronated position to neutral © 2007 McGraw-Hill Higher Education. All rights reserved. 6-29 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-30 5 Triceps Brachii Muscle Anconeus Muscle All heads: extension of elbow Long head: extension of shoulder Extension of elbow joint; adduction of shoulder joint; horizontal abduction © 2007 McGraw-Hill Higher Education. All rights reserved. 6-31 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-32 Pronator Teres Muscle Pronator Quadratus Muscle Pronation of Pronation forearm of forearm Weak flexion of elbow © 2007 McGraw-Hill Higher Education. All rights reserved. 6-33 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-34 Supinator Muscle Elbow Flexion • Ex. Biceps curl • Agonists – Biceps brachii – Brachialis Supination of – Brachioradialis forearm © 2007 McGraw-Hill Higher Education. All rights reserved. 6-35 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-36 6 Elbow Extension Radioulnar Pronation • EX. Push-up • Agonists • Agonists – Pronator teres – Triceps brachii – Pronator • Anconeus quadratus – Brachioradialis © 2007 McGraw-Hill Higher Education. All rights reserved. 6-37 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-38 Radioulnar Supination Web Sites American Family Physician • Ex. Tightening a http://www.aafp.org/afp/20000201/691.html – Evaluation of Overuse Elbow Injuries screw Medical Multimedia Group www.healthpages.org/AHP/LIBRARY/HLTHTOP/CTD/ • Agonists – A Patient's Guide to Cumulative Trauma Disorder(CTD) – Biceps brachii