Chapter 6 the Elbow and Radioulnar Joints

Home , Anconeus muscle, Biceps, Brachialis muscle, Brachioradialis, Elbow, Forearm

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

Brachialis Muscle Brachioradialis Muscle

True Flexion of elbow flexion Pronation from supinated of elbow position to neutral

Supination from pronated position to neutral

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

Pronator Teres Muscle Pronator Quadratus Muscle

Pronation of Pronation forearm of forearm

Weak flexion of elbow

Supinator Muscle Elbow Flexion • Ex. Biceps curl • Agonists – Biceps brachii – Brachialis Supination of – Brachioradialis forearm

6 Elbow Extension Radioulnar Pronation

• EX. Push-up • Agonists • Agonists – Pronator teres – Triceps brachii – Pronator • Anconeus quadratus – Brachioradialis

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 Lecture Topics in Kinesiology http://moon.ouhsc.edu/dthompso/namics/elbow.htm – Supinator muscle – Describes motions caused by the muscles. Huei Ming Chai – Brachioradialis www.pt.ntu.edu.tw/hmchai/Kines04/KINupper/Elbow.htm – Functions, stability and joint structure of elbow complex; kinematics, muscle action and common injuries of the elbow. Southern California Orthopedic Institute www.scoi.com/teniselb.htm – Tennis elbow information

Web Sites Web Sites

National Aeronautics and Space Administration American Physical Therapy Association http://rehabworks.ksc.nasa.gov/education/protocols/basicwristel http://www.apta.org/AM/Template.cfm?Section=Home&CONTE bow.php NTID=20403&TEMPLATE=/CM/HTMLDisplay.cfm – Basic Wrist and Elbow Rehabilitation – Taking Care of Your Hand, Wrist, and Elbow UpToDate The Physician and Sportsmedicine http://patients.uptodate.com/topic.asp?file=bone_joi/7086 http://www.physsportsmed.com/issues/1996/05_96/nirschl.htm – Physical Therapy for Elbow Tendinitis – Assessment and Treatment Guidelines for Elbow Injuries American Sports Medicine Institute The Physician and Sportsmedicine www.asmi.org/asmiweb/mpresentations/mmp.htm http://www.physsportsmed.com/issues/1999/06_99/whiteside.ht – Biomechanics of the Elbow during Throwing m American Academy of Orthopaedic Surgeons – Elbow Injuries in Young Baseball Players http://orthoinfo.aaos.org/category.cfm?topcategory=Hand Radiologic Anatomy Browser – Patient Education Library on the Elbow http://radlinux1.usuf1.usuhs.mil/rad/iong/index.html – This site has numerous radiological views of the musculoskeletal system.

7 Web Sites Web Sites

University of Arkansas Medical School Gross Anatomy for Premiere Medical Search Engine Medical Students http://www.medsite.com/Default.asp?bhcp=1 http://anatomy.uams.edu/anatomyhtml/grossresources.html – This site allows the reader to enter any medical condition and – Dissections, anatomy tables, atlas images, links, etc. it will search the net to find relevant articles. Loyola University Medical Center: Structure of the Human Body Virtual Hospital www.meddean.luc.edu/lumen/MedEd/GrossAnatomy/GA.html www.vh.org – An excellent site with many slides, dissections, tutorials, etc., – Numerous slides, patient information, etc. for the study of human anatomy Wheeless’ Textbook of Orthopaedics www.wheelessonline.com/ – This site has an extensive index of links to the fractures, joints, muscles, nerves, trauma, medications, medical topics, lab tests, and links to orthopedic journals and other orthopedic and medical news. Arthroscopy.Com www.arthroscopy.com/sports.htm – Patient information on various musculoskeletal problems of the upper and lower extremity © 2007 McGraw-Hill Higher Education. All rights reserved. 6-43 © 2007 McGraw-Hill Higher Education. All rights reserved. 6-44