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Jenelle Beadle, RDMS Inland Imaging November 4 th , 2014 Muskuloskeletal Sonography • Muscles, tendons, ligaments & bursae • Histologic anatomy and ultrasound appearance correlation • Common abnormalities visualized using ultrasound In the human body, there are… …650 skeletal muscles. …4000 tendons. …900 ligaments. … 160 bursae. Muscles • Isoechoic/hypoechoic (compared to fat) • Linear hypoechoic bundles (fascicles) surrounded by echogenic perimysium • Epimysium & Fascia: single, hyperechoic line at the muscle boundary (arrows) • Perimysium: innumerable hyperechoic lines (arrowheads) • Fascicles: hypoechoic bundles of muscle fibers in between • Muscles are typically evaluated with ultrasound for pain and/or a palpable abnormality. • Often times with a history of traumatic injury • Most common abnormal findings include strains/tears and tumors. Intramuscular Sarcoma Adductor Magnus Muscle Intramuscular Myxoma Gastrocnemius Rupture Normal • Muscle strains/tears most commonly occur in the lower extremity • • typically near the musculotendinous junction severity of muscle strain injuries are graded I, II or III • Strain (Grade I): pain; resolves in about 2 weeks • • normal thickened and hyperechoic • Muscle strains/tears most commonly occur in the lower extremity • • typically near the musculotendinous junction severity of muscle strain injuries are graded I, II or III • Strain (Grade I): pain; resolves in about 2 weeks • • normal thickened and hyperechoic With a contusion, echogenicity may cross fascial boundaries. • Tear (Grade II): pain with loss of function; resolves in about 4 weeks • intrasubstance tears; detachment from fascia or aponeurosis • disruption of striated pattern • intramuscular fluid collection with hyperechoic halo (hypervascular) “Tennis Leg” Trans Long • Avulsion (Grade III): pain with loss of function, usually caused by strong contraction against firm resistance • myotendinous (muscle to tendon) or tendoosseous (tendon to bone) • complete discontinuity of muscle fibers; hematoma Musculotendinous junction tear Tendons (muscle-to-bone) • Echogenic (compared to muscle) • Linear fibril bundles of collagen in a supporting matrix • Short axis: “finely punctate pattern” • multiple echogenic dots • Long axis: “fibrillar architecture” • multiple, closely spaced parallel lines Trans Long Long Patellar Tendon Anisotropy artifact Anisotropy Trans Achilles Tendon Tendinopathy • Sonographic evaluation: size/thickness, contour and echotexture • Dynamic scanning can also be helpful • Tendinosis • • • • • thickened, hypoechoic, hypervascular; may have some loss of fibrillar pattern occurs with or without tendon tears Acute: strained by traumatic injury Chronic: general wear-and-tear (age-related changes, inflammatory disorders) • may have calcifications present (calcific tendinosis); round or linear in shape Chronic tendinosis predisposes a tendon to further injury • As a result, tendons that typically affected by overuse or degeneration are also the tendons most commonly strained or torn. • Supraspinatus, achilles, patellar, quadriceps and common extensor (elbow) tendons • Achilles Tendinosis • Common Extensor Tendinosis (lateral epicondylitis) • “Tennis Elbow” (although 95% are not in tennis players) • usually results from repetitive motion injuries (chronic) Normal Common Extensor Tendon Supraspinatus Tendonisis Quadriceps/Patellar Tendinosis Tendon Tears/Ruptures • Acute or Chronic • most tendon tears are a result of chronic overuse rather than acute trauma • Associated with adjacent tendinosis • makes identifying small partial tears difficult • Ultrasound Findings (often more easily appreciated with dynamic scanning) • partial/complete nonvisualization • distinct focal hypoechoic/anechoic defect • apparent disruption of linear fibrillar architecture • contour abnormality • Most commonly torn tendons are supraspinatus and achilles • Tears are categorized • partial • full thickness (complete rupture) • Partial Tear • a portion of the tendon remains intact • includes “intratendinous” tears Long Achilles Tendon Long Common Extensor Tendon Long Distal Biceps Tendon Trans Peroneal Longus/Brevis Tendons • Partial Tear • with a large partial tear, some retraction of the torn tendon may be identified Long Quadriceps Tendon Trans Achilles Tendon • Full Thickness Tear • rupture that extends across the entire width and depth of the tendon • proximal muscular retraction of the entire tendon • non-functional tendon distal at insertion Long Patellar Tendon Long Achilles Tendon Prox Dist Complete achilles rupture with intact plantaris tendon • absent 7-20% Long Achilles Rupture Trans Achilles Rupture Ligaments (bone-to-bone) • Isoechoic/hypoechoic (compared to tendons) • Similar composition as tendons, but fibers are less organized structure; more of an interlaced, woven pattern. • Fibrillar pattern, but slightly changing the orientation of the tranducer will bring other fibers into view. • This less regular structure is what makes ligaments slightly less echogenic than tendons. • Injury is often associated with joint derangement (acute). • Sprain: stretching or tearing of a ligament (“strain”- tendon) • Range from invisible “micro-tears” to complete rupture • Most commonly injured ligaments are in the knee and ankle • Ankle Ligaments • Anterior Talofibular Ligament (most commonly injured) • anterior lateral malleolus to anterior talus • best seen in w/ tendon stressed (plantar flexion) • injured with supination (lateral rotation of the ankle) • iIsolated, or associated with Calcaneofibular Ligament (up to 70%) peroneal tendons • Ligament Sprain/Rupture • Thickened & hypoechoic with surrounding fluid • Evidence of tear may be seen (hypoechoic area that interrupts fibers) Ruptured Anterior Talofibular Ligament Normal “a”: anterior talofibular ligament “b”: calcaneofibular ligament Curved lines: peroneal tendons • Knee • ACL: Anterior Cruciate Ligament (can’t be seen well enough with ultrasound) • PCL: Posterior Cruciate Ligament (not commonly injured) • Lateral Collateral Ligament (not commonly injured) • Medial Collateral Ligament Medial Meniscus (purple) & Medial Collateral Ligament (green) Bursae • Thin layer of anechoic fluid (synovial) surrounded by hyperechoic walls. • Not typically visualized unless abnormal. • Synovial-lined sac overlying bony surfaces at areas of tendon friction. • Some communicate with the joint space (ex: semimembranosus bursa) • Baker’s Cyst (Popliteal Cyst) typically communicates with the joint capsule via the semimembranosus bursa. • Bursitis: • Repetitive motion and overuse • Inflammatory disorders (rheumatoid arthritis, gout, etc.) • Shoulder, elbow , hip & knee • Most common site: Subacromial Bursa (shoulder) • Does not normal communicate with the joint space, but can if there is a full thickness tear. Subacromial Bursitis • Other common sites of bursitis… • Prepatellar Bursa (“housemaid’s knee”) • Infrapatellar Bursa (“clergyman’s knee”) Prepatellar Bursitis Infrapetellar Bursitis Deep Infrapatellar Bursitis • Other common sites of bursitis… • Trochanteric (lateral hip) Trochanteric Bursitis Trochanteric Bursitis (Deep) • Between the greater trochanter and the gluteus medius muscle insertion. Gluteus Medius Insertion • Other common sites of bursitis… • Iliopsoas Bursa Long Iliopsoas Bursitis Trans Iliopsoas Bursitis • Other common sites of bursitis… • Olecranon Bursa (“student’s elbow”) Triceps Tendon Long Olecranon Bursitis Trans Olecranon Bursitis References • “Skeletal Muscle Ultrasound” European Journal Translational Myology 2010; 1 (4): 145155 • “Ultrasonographic Findings of Musculoskeletal Tissues” J Korean Orthop Assoc. 2013 Oct;48(5):334-341 • “Sonography of Common Tendon Injuries” American Journal of Roentgenology. 2009;193: 607-618 • “Tendon and Ligament Imaging” Br J Radiol. Aug 2012; 85(1016): 1157–1172 • “Imaging of the Bursae” J Clin Imaging Sci 2011; 1:22 • “Ultrasonography of tendon abnormalities” OA Musculoskeletal Medicine 2013 Jun 01;1(2):12 • “Sonography of Lower Limb Muscle Injury” American Journal of Roentgenology. 2004;182: 341-351 • “Full Thickness and Partial Thickness Supraspinatus Tendon Tears” Radiology 2004; 230:234–242 • “Long Head of Biceps Brachii Tendon Evaluation...” AJR 2011; 197:942–948 • “Ultrasound of the Shoulder” JBR–BTR, 2007, 90: 325-337 • Gaitini D. “Shoulder Ultrasonography: Performance and Common Findings” J Clin Imaging Sci 2012; 2: 38-38 • Read J, Perko M. “Ultrasound Diagnosis of Subacromial Impingement for Lesions of the Rotator Cuff” AJUM May 2010; 13 (2): 11-15 References (continued…) • http://www.sonoguide.com/soft_tissue.html • http://www.dynamicultrasound.org/dugphysics.html • http://www.ultrasoundcases.info/Slide-View.aspx?cat=405&case=1858 • http://www.shoulderdoc.co.uk/article.asp?section=904 • http://www.radiologyassistant.nl/en/p50cf8392cbd97/us-guidedinjection-of-joints.html • http://radiopaedia.org/articles/posterosuperior-impingement-of-thshoulder