Download MSK US of the Elbow Normal by Jon Finnoff DO

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
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Anterior
•
•
•
3 anterior joint recesses
• Coronoid
• Radial
• Annular
Have intra-articular, extra-synovial
hyperechoic fat pads
Minimal fluid normally
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Anterior
•
•
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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
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• 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
•
•
•
•
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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