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Download MSK US of the Elbow Normal by Jon Finnoff DO
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Musculoskeletal Ultrasound of the Elbow Jonathan Finnoff, DO Medical Director, Mayo Clinic Sports Medicine Center, Minneapolis, MN Team Physician: US Ski Team, Timberwolves, Lynx ©2014 MFMER | 3375858-1 Disclosures • I receive royalties from Demo’s Publishing for a sports medicine book I co-edited. ©2014 MFMER | 3375858-2 Anterior • Biceps and brachialis muscle • Hypoechoic muscle with normal “starry night” appearance in cross-section • Scanning distally, biceps becomes tendinous • Can see musculocutaneous nerve between the two muscles • If long-head of biceps muscle is ruptured, lateral aspect of the biceps muscle (long head of the biceps portion) will be hyperechoic (due to fibrofatty infiltration) and atrophic ©2014 MFMER | 3375858-3 Anterior • Antecubital “triangle” • Brachialis pyramid in center of screen bisected by hyperechoic brachialis tendon • Biceps tendon sitting at apex of triangle • Brachial artery followed by median nerve are medial to biceps tendon • Trochlear and capitellar cartilage deep • Brachioradialis lateral • Radial nerve between brachioradialis and brachialis • Pronator teres medial ©2014 MFMER | 3375858-4 Anterior • • • 3 anterior joint recesses • Coronoid • Radial • Annular Have intra-articular, extra-synovial hyperechoic fat pads Minimal fluid normally ©2014 MFMER | 3375858-5 Anterior • • ©2014 MFMER | 3375858-6 Radial nerve travels distally between brachioradialis and brachialis Divides into superficial and deep branch • Superficial branch travels distally toward the wrist deep to the brachioradialis • Deep branch • Crosses over or under radial recurrent artery • Passes through Arcade of Froshe into supinator muscle and traverses muscle between 2 bellies • Becomes PIN and exits into dorsal forearm Anterior • 3 similar sized structures in anteromedial elbow – from medial to lateral • Median nerve, brachial artery, biceps tendon • As median nerve travels distally, it passes between the humeral and ulnar heads of the pronator teres (site of entrapment) • Ulnar head of pronator teres passes between median nerve and ulnar artery ©2014 MFMER | 3375858-7 Anterior Smith J Ultrasound Med 2010 ©2014 MFMER | 3375858-8 • The distal biceps tendon can be difficult to image due to its steep dive to the radial tuberosity • Instead, can image from medial (pronator window) or lateral view • Allows sound wave to hit biceps tendon perpendicular to its fibers, eliminates anisotropy • With pronator window, can see biceps insertion on radial tuberosity • Perform dynamic evaluation to determine if intact Medial • Tendon on more anterior aspect of medial epicondyle • Flexor-pronator tendon is shorter than common extensor tendon • Pronator teres is first and most medial muscle to arise off flexor-pronator tendon ©2014 MFMER | 3375858-9 Medial • Ulnar collateral ligament has 3 bands • Anterior (thickest) • Posterior • Transverse • Anterior band most important stabilizer to valgus stress with elbow flexed 90 degrees • Located on posterior aspect of medial epicondyle • Inserts on sublime tubercle of ulna • Small joint recess deep to ligament ©2014 MFMER | 3375858-10 Medial • • • • ©2014 MFMER | 3375858-11 Ulnar nerve is easily identified posterior to medial epicondyle Surrounded by peri-neural fat in retro-condylar region, and held in place by Osborne’s fascia Cubital tunnel: where ulnar nerve passes under arcuate ligament, between two heads of flexor carpi ulnaris Evaluate for subluxation/dislocation by flexing elbow • Dislocates in 20% of asymptomatic individuals, so correlate with symptoms and sonographic findings of nerve injury Posterior • • • ©2014 MFMER | 3375858-12 Triceps has 3 heads • Long • Medial • Lateral Radial nerve traverses arm in radial groove between medial and lateral heads Distal tendon composition • Lateral and long head fuse to form more superficial aspect of tendon • Medial head forms deep portion of tendon Posterior • Olecranon recess in olecranon fossa • Most common elbow joint recess for fluid to accumulate • Can also have loose bodies ©2014 MFMER | 3375858-13 Lateral • Brachioradialis and extensor carpi radialis longis originate proximal to the lateral epicondyle • Extensor carpi radialis brevis, extensor digitorum communis, and extensor carpi ulnaris originate from lateral epicondyle • Most common tendon involved in lateral epicondylosis = ECRB • Lateral synovial fringe = plical/synovial remnant in lateral joint between radial head and capitellum • Can cause pain +/- snapping ©2014 MFMER | 3375858-14 Lateral • Radial collateral ligament complex • Radial collateral ligament • Annular ligament • Lateral ulnar collateral ligament • Radial collateral ligament difficult to differentiate from extensor tendons ©2014 MFMER | 3375858-15 Live Scanning Demonstration ©2014 MFMER | 3375858-16 Thank You ©2014 MFMER | 3375858-17
