Journal of Ultrasound in MedicineEarly View Practice ParameterFree Access The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination First published: 05 April 2023 https://doi.org/10.1002/jum.16228AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Introduction The American Institute of Ultrasound in Medicine (AIUM) is a multidisciplinary association dedicated to advancing the safe and effective use of ultrasound in medicine through professional and public education, research, development of clinical practice parameters, and accreditation of practices performing ultrasound examinations. The AIUM Practice Parameter for the Performance of the Musculoskeletal Ultrasound Examination was revised by the American Institute of Ultrasound in Medicine (AIUM) in collaboration with other organizations whose members use ultrasound for performing this examination(s) (see “Acknowledgments”). Recommendations for personnel requirements, the request for the examination, documentation, quality assurance, and safety may vary among the organizations and may be addressed by each separately. This Practice Parameter is intended to provide the medical ultrasound community with recommendations for the performance and recording of high-quality ultrasound examinations. The parameters reflect what the AIUM considers the appropriate criteria for this type of ultrasound examination but is not intended to establish a legal standard of care. Examinations performed in this specialty area are expected to follow the Parameter with recognition that deviations may occur depending on the clinical situation. Indications Indications for musculoskeletal ultrasound include, but are not limited to: Pain or dysfunction Soft tissue or bone injury Tendon, ligament, or fascial pathology Arthritis, synovitis, or crystal deposition disease Joint effusion and intraarticular bodies Neurovascular entrapment, injury, neuropathy, mass, or subluxation Evaluation of soft tissue masses, swelling, or fluid collections Detection of foreign bodies in the superficial soft tissues Planning and guidance for an invasive procedure Congenital or developmental anomalies Postoperative or postprocedural evaluation Joint laxity, stiffness, decreased range of motion, or misalignment The above is a comprehensive list of general indications for musculoskeletal ultrasound; however, specific and unique indications pertaining to specific joints will be listed in the corresponding sections. Musculoskeletal ultrasound should be performed when there is a valid medical reason. There are no absolute contraindications. Qualifications and Responsibilities of Personnel Physicians interpreting or performing this type of ultrasound examination should meet the specified AIUM Training Guidelines1 in accordance with AIUM accreditation policies.2 Sonographers performing the ultrasound examination should be appropriately credentialed3 in the specialty area in accordance with the AIUM accreditation policies.2 Physicians not personally performing the examination must provide supervision, as defined by the Centers for Medicare and Medicaid Services Code of Federal Regulations 42 CFR §410.32.4 Physician A physician must be available for consultation with the sonographer on a case-by-case basis. Ideally the physician should be on-site and available to participate actively in the ultrasound examination when required. It is recognized, however, that geographic realities may not permit the presence of an on-site physician in all locations. In this case, a supervising physician should be available for quality assurance and sonographer supervision via a picture archiving and communication system (PACS). Request for the Examination The written or electronic request for an ultrasound examination must originate from a physician or other appropriately licensed healthcare provider or under the provider's direction. The clinical information provided should allow for the performance and interpretation of the appropriate ultrasound examination and should be consistent with relevant legal and local healthcare facility requirements.2 Specification of the Examination The written or electronic request for a musculoskeletal ultrasound examination should provide sufficient information to demonstrate the medical necessity of the examination and allow for its proper performance and interpretation. Documentation that satisfies medical necessity includes 1) signs and symptoms and/or 2) relevant history (including known diagnoses). Additional information regarding the specific reason for the examination or a provisional diagnosis would be helpful and may at times be needed to allow for the proper performance and interpretation of the examination. General Principles Depending on the clinical request and the patient's symptoms, the ultrasound examination may involve a complete assessment of a joint or an anatomic region, or it may be limited to a specific anatomic structure. Examinations of joints, such as the elbow, hip, knee, and ankle, can be divided into four regions (anterior, medial, lateral, and posterior). A complete examination includes evaluation of the joint and synovium, cortical outline of underlying bones, muscles, tendons and tendon sheaths, ligaments and fascia, capsule, and any additional abnormalities visible in the region. Color and power Doppler may be useful in detecting hyperemia or neovascularity within the tendon and/or tendon sheath, joint, or surrounding structures. Doppler flow is considered a key imaging finding for some pathologic conditions in musculoskeletal ultrasound. The equipment must be optimized for relevant Doppler sensitivity. Images should always be obtained with the ultrasound beam perpendicular to the region of interest to minimize artifact. When applicable, relevant structures should be interrogated in more than 1 plane, at least 2 orthogonal planes. Patient positioning for specific examinations may vary depending on the structure being examined, the patient's clinical condition, and the operator's preference to obtain required short-axis and long-axis images. Dynamic evaluation is an important aspect of all musculoskeletal exam protocols to test for mobility, subluxation/dislocation, or impingement. Transducer movements and manipulation are critical to provide accurate ultrasound images in musculoskeletal ultrasound. Heel-toe and tilting maneuvers help in avoiding anisotropy artifact by changing the angle of insonation while maintaining contact with the skin surface. Sometimes compression with the transducer may be performed to evaluate for solid versus cystic/fluid-filled structures and/or to elicit symptoms (sonopalpation). Specifications of the Shoulder Examination A shoulder examination is requested to evaluate for rotator cuff pathology such as a partial- or full-thickness tear, calcific tendinitis, or tendinosis in adults, and joint-centered pathology in children. Other indications include evaluation of biceps tendon pathology, including tendon instability, subacromial-subdeltoid hypertrophy/bursitis, acromioclavicular arthritis, paralabral cyst, and nerve compression. The long head of the biceps tendon is examined in a transverse plane (short axis) within the bicipital groove and to the musculotendinous junction distally. The insertions of the pectoralis major tendon on the humerus can be evaluated at the same time, when indicated. Longitudinal views (long axis) should also be obtained. Tendon position within the bicipital groove should be commented upon. Dynamic evaluation may be performed in the short axis to evaluate for tendon subluxation or dislocation. The subscapularis is imaged from the musculotendinous junction to the insertion on the lesser tuberosity of the humerus in long-axis and short-axis planes. Dynamic evaluation in the long-axis plane is helpful to evaluate possible subcoracoid impingement. When scanning the supraspinatus and infraspinatus tendons along their long axes, it is important to orient the transducer in an oblique plane. Short-axis views of the tendons should also be obtained by rotating the transducer 90° to the long axis. Correct short-axis positioning may be confirmed by visualizing the coracohumeral ligament in long axis medially, then moving laterally along the shoulder. Additionally, a short-axis view of the long head biceps in the rotator interval can serve as a landmark for appropriate orientation to the supraspinatus and infraspinatus tendons in short axis. When necessary, the more posterior aspect of the infraspinatus and teres minor tendons can be examined by placing the transducer posteriorly at the level of the glenohumeral joint. During the examination of the rotator cuff, the cuff should be frequently compressed with the transducer to detect nonretracted tears. Dynamic evaluation of the rotator cuff during shoulder abduction is useful to evaluate the rotator cuff for subacromial or subligamentous impingement. Tear length (partial-thickness tear) or the degree of retraction of the cuff (full-thickness tear) should be measured on longitudinal views, and tear width should be measured on short-axis views. Tear depth should also be assessed. A partial-thickness tear should be described as originating from the bursal or articular side, or intrasubstance, and its thickness should be assessed. It is also useful to measure the distance between the intra-articular portion of the biceps tendon and the anterior edge of the tear on short-axis views; most degenerative tears begin ~15 mm from the intra-articular portion of the biceps tendon.5 In patients with a rotator cuff tear, the supraspinatus, infraspinatus, and teres minor muscles should be examined for fatty infiltration and atrophy, because these findings may influence the postoperative outcomes. Comparison with the contralateral rotator cuff muscles is often helpful to confirm muscle atrophy and fatty infiltration except when muscle atrophy is the result of a diffuse systemic process. Rotator cuff thickness and echogenicity should also be evaluated; a thick, hypoechoic cuff indicates tendinosis. The postoperative (rotator cuff after repair) rotator cuff may be hypoechoic and/or heterogenous in the early healing period, but that appearance may resolve over a period of time.6 The subacromial–subdeltoid bursa should be examined for the presence of synovial hypertrophy or effusion. Power or color Doppler should also be used to detect hyperemia. Bursal bunching and snapping in the setting of subcoracoid, subacromial, and subligamentous impingement can be assessed with dynamic examination. Glenohumeral joint effusion is best assessed via a posterior approach. Glenohumeral effusion typically lacks Doppler flow and can be displaceable, whereas synovial thickening can contain Doppler flow and is not or only minimally compressible. Posterior labral abnormalities should also be evaluated using this approach. If symptoms warrant, the suprascapular notch and spinoglenoid notch may also be evaluated for a paralabral cyst. The acromioclavicular joint should be evaluated for arthritis, infection, or trauma by placing the transducer at the apex of the shoulder, over the acromion and distal clavicle.7-10 Ultrasound is very useful as the first line of screening of infants and young toddlers with clinically suspected glenohumeral dysplasia. It serves as an alternative to MRI, which provides a more global assessment, providing complementary information without the need for patient sedation. These infants are typically examined in the seated position on the caregiver's lap, facing away from the sonographer. Alternatively, the children can also be scanned in a decubitus position. Each shoulder, both symptomatic and normal sides, is scanned via a posterior approach to evaluate the morphology and alignment between the humeral head and glenoid. Both static and dynamic images are obtained with the shoulder in neutral position and full internal and external rotation. Posterior subluxation is evaluated qualitatively and quantitatively, with the latter involving the use of the α angle and humeral head translation. The α angle is formed between a line drawn along the posterior margin of the scapula and a line drawn tangentially to the posterior cortex of humeral head and posterior edge of the glenoid. An α angle of 30° or less is considered normal. Humeral head translation measures the percentage of the humeral head that is displaced posterior to the axis of the scapula. The normal value for humeral head translation is 50% or less. Muscle atrophy is characterized by asymmetric decreased thickness and bulk when compared with the contralateral normal side. In infants with equivocal radiographs, the clavicle and proximal humerus can be evaluated for displaced fractures secondary to birth trauma11 or nonaccidental trauma. In the latter scenario, the proximal humerus can be assessed for Salter–Harris fractures. However, it is worth noting that nondisplaced fractures and incomplete fractures involving the cortex that are inaccessible by ultrasound can be subtle and missed, respectively. These can be assessed using follow-up radiographs. In infants with Erb's palsy and history of shoulder dystocia, ultrasound is useful for mapping out injuries to the brachial plexus, associated muscle denervation injuries, and glenohumeral subluxation.12 Ultrasound can be helpful intraoperatively to confirm glenohumeral reduction. Specification of an Elbow Examination Examination of the elbow is divided into four regions: anterior, medial, lateral, and posterior. Anterior The anterior joint space and other recesses of the elbow are assessed for joint or bursal effusion, synovial hypertrophy, and intra-articular bodies. Longitudinal and transverse scanning of the anterior humeroradial joint, the humeroulnar joint, and both the coronoid and radial fossae is performed to assess the articular cartilage and cortical bone. The annular recess of the neck of the radius is scanned dynamically with forearm pronation and supination. The same dynamic assessment can be made for the biceps brachii tendon and its attachment to the radial bicipital tuberosity. When evaluating the distal biceps tendon from an anterior approach, the arm should be maximally supinated and extended. The distal biceps tendon can also be evaluated from a medial approach with the elbow flexed and the forearm supinated13 or via a lateral approach14 using the brachioradialis as an acoustic window. The insertion can also be imaged during dynamic scan with a posterior approach. Evaluation of the brachialis muscle, the adjacent radial and brachial vessels, and the median and radial nerves can also be performed as clinically warranted. Lateral Lateral elbow evaluation allows assessment of the lateral epicondyle, the attachments of the common extensor tendon, and the proximal attachments of the extensor carpi radialis longus and brachioradialis. Scanning the posterolateral aspect of the elbow allows evaluation of the lateral collateral ligament complex. The radial nerve, including its deep branch entering the supinator muscles (posterior interosseous nerve), is also evaluated. Medial Medial elbow scanning includes evaluation of the medial epicondyle, common flexor tendon, and ulnar collateral ligament.15, 16 The ulnar nerve is visualized in the cubital tunnel region between the olecranon process and medial epicondyle. Dynamic subluxation and dislocation of the ulnar nerve and adjacent medial head of the triceps muscle are assessed by imaging with flexion and extension of the elbow. Dynamic examination with valgus stress is performed to assess integrity of the ulnar collateral ligament. During valgus stress testing, the elbow may have to be flexed at variable angles to disengage the olecranon from the olecranon fossa. Posterior To evaluate the posterior elbow, the elbow is flexed to 90°. The posterior joint space, triceps brachii tendon, olecranon process, and olecranon bursa are assessed.17-19 In infants, who have not yet developed any elbow ossification centers, radiographic distinction between elbow dislocation and transphyseal fracture-displacement is challenging. Ultrasound can be helpful in this situation, made even more useful by comparison imaging of the contralateral, normal side. Placing the transducer in the longitudinal plane anteriorly or anterolaterally on the elbow can confirm the normal radiocapitellar alignment in the absence of a dislocation. It can assess for disruption at the level of the humeral physis too. Similarly, ultrasound can identify the components of a lateral condyle fracture when the distal humeral epiphysis is not yet ossified and fracture components are radiographically occult. Specifications of the Wrist Examination A wrist examination may be indicated to evaluate a focal abnormality such as a tumor (tenosynovial giant cell tumor of the tendon sheath, peripheral nerve sheath tumor, or lipoma), ganglion, epidermal inclusion cyst, foreign body, or tendon injury. Tenosynovitis, nerve entrapment syndromes, and peripheral nerve disorders such as carpal tunnel syndrome can also be evaluated. In the patient with suspected inflammatory arthritis, the hands and wrists should be evaluated for synovial hypertrophy, joint effusion, bony erosions, tenosynovitis, crystal deposition, and tendon rupture. The examination may include a complete assessment of one or more of the four anatomic regions described below or may be limited to a specific anatomic structure, depending on the clinical presentation. Volar Transverse and longitudinal images should be obtained from the volar wrist crease to the thenar muscles. The transducer will require angulation changes to compensate for the normal contour of the wrist and to minimize anisotropy. The flexor retinaculum, flexor digitorum profundus, superficialis tendons, and the adjacent flexor pollicis longus tendon should be identified within the carpal tunnel. Dynamic imaging with flexion and extension of the fingers will demonstrate the normal motion of these tendons. The median nerve normally lies superficial to these tendons and deep to the flexor retinaculum. The distal portion of the median nerve tapers and divides into multiple branches for the hand. The palmaris longus tendon lies superficial to the retinaculum, if present. Radial On the radial side of the wrist, the flexor carpi radialis longus tendon lies within its own canal. It is important to evaluate the region of the flexor carpi radialis and the radial artery for occult ganglion cysts, which can originate from the radiocarpal joint capsule, scapho-trapezial joint, or flexor carpi radialis tendon sheath itself. All of the tendons can be followed to their sites of insertion if clinically indicated. Ulnar Placing the transducer transversely on the ulnar styloid and moving distally will allow visualization of the triangular fibrocartilage complex (TFCC) in its long axis. Dynamic imaging with radial deviation may be helpful in assessing the integrity of the TFCC. The transducer is then rotated 90° to view the short axis of the TFCC. The ulnomeniscal homologue may be seen just deep to the extensor carpi ulnaris tendon. The extensor carpi ulnaris tendon should be viewed in supination and pronation to assess for subluxation. In the setting of inflammatory arthritis, the extensor carpi ulnaris should be evaluated for tenosynovitis and rupture. On the ulnar side, branches of the ulnar nerve and artery lie within the ulnar tunnel. The flexor carpi ulnaris tendon and pisiform bone border the ulnar aspect of the tunnel. Dorsal Because the dorsal structures are very superficial, a high-frequency transducer, even using a stand-off gel, is necessary to optimize the examination and prevent compression of small vessels when using color or power Doppler. The extensor retinaculum divides the dorsal aspect of the wrist into six compartments, which accommodate nine tendons. These tendons are examined in their short axes initially and then in their long axes statically and dynamically, the latter being performed with flexion and extension of the fingers. The tendons can be followed to their sites of insertion when clinically indicated. Moving the transversely positioned transducer distal to Lister's tubercle identifies the dorsal aspect of the scapholunate ligament, a potential site of symptomatic ligament tears and ganglion cysts that may be evaluated with and without stress maneuvers. The remaining intercarpal ligaments are not routinely assessed. Specifications of Hand Ultrasound In patients with suspected inflammatory arthritis, the dorsal radiocarpal, distal radioulnar, midcarpal, metacarpophalangeal, and, if symptomatic, the interphalangeal joints are evaluated from the volar and dorsal aspects in both the longitudinal and transverse planes for effusion, synovial hypertrophy, synovial hyperemia, and bony erosions.20, 21 This component of the examination can be extended as clinically warranted to evaluate the flexor/extensor tendons and their pulleys for injuries and/or tenosynovitis. In the event of trauma, ultrasound can be used to detect avulsion fractures that may be associated with tendon injuries. Specific to the thumb, the ulnar collateral ligament may be evaluated with and without stress maneuvers. Specifications of a Hip Examination Depending on the patient's body habitus, a lower frequency transducer may be required to scan the hip. However, the operator should use the highest possible frequency that provides adequate penetration. The examination is divided into four regions: anterior, medial, lateral, and posterior. Anterior In the supine position, a sagittal oblique plane parallel to the long axis of the femoral neck is used for evaluating the femoral head and neck and for detecting joint effusion or synovitis. The lower extremity should be rotated externally. The sagittal and axial planes are used to visualize the anterior labrum, the iliopsoas tendon and bursa, the femoral vessels, and the sartorius and rectus femoris tendon origins.22 When an extra-articular cause of anterior “snapping hip” is suspected, dynamic scanning is performed over the region of interest using the same movement that the patient describes as precipitating the snap, usually precipitated by hip flexion and external rotation. This snap commonly occurs anteriorly, as the iliopsoas tendon crosses over the acetabular eminence.23 Recent literature adds that the interchange of the muscle belly and the tendon is more likely the cause of a snap rather than the tendon snapping over the underlying acetabular eminence.23 Lateral In the lateral decubitus position with the symptomatic side up, transverse and longitudinal scans of the greater trochanter, greater trochanteric bursae, gluteus medius, gluteus maximus, gluteus minimus, iliotibial band, and tensor fasciae latae should be performed. Sonopalpation of the greater trochanter can be performed when assessing for trochanteric bursitis. An iliotibial band or gluteus maximus muscle that snaps over the greater trochanter can be assessed in this position using dynamic flexion extension of the hip. Medial The hip is placed in external rotation with 45° knee flexion (frog-leg position). The distal iliopsoas tendon, because of its oblique course, may be better seen in this position. The adductor muscles and their origins from the pubic tubercle are imaged in their long axes with the probe in a sagittal oblique orientation. Short-axis images are obtained perpendicular to this plane. In addition, the pubic bone and symphysis, the distal rectus abdominis, and adductor origin should be evaluated for musculotendinous or aponeurotic injury.24 Posterior The patient is prone with the lower extremities extended. Transverse and longitudinal views of the glutei, hamstring tendons, and sciatic nerve are obtained. The glutei are imaged obliquely from their origins to the greater trochanter (gluteus medius and minimus) and linea aspera (gluteus maximus). The sciatic nerve is scanned in its short axis starting at its exit at the greater sciatic foramen, deep to the gluteus maximus. It can be followed distally, midway between the ischial tuberosity and the greater trochanter, lying superficial to the quadratus femoris muscle.25 The hamstring tendons can be assessed in transverse and long axis for the presence of tears and tendinosis. The ischial bursa is not typically seen unless an effusion or thickening is present in the setting of bursitis. For further detail on the examination of the pediatric hip for hip dysplasia, see the AIUM–ACR–SPR–SRU Practice Parameter for the Performance of an Ultrasound Examination for Detection and Assessment of Developmental Dysplasia of the Hip.26 Specifications of a Prosthetic Hip Examination The prosthetic hip is assessed for joint effusions, extra-articular fluid collections, iliopsoas bursitis, or soft tissue masses and/or necrosis (adverse local tissue reaction). Ultrasound guidance may be requested to evaluate for fluid aspiration in the clinical scenario of a possible prosthetic joint infection. The region of the greater trochanter and iliopsoas is evaluated for fluid collections or tendon abnormalities, such as tendinosis or tear of the iliopsoas, gluteus medius, or gluteus minimus tendons.27, 28 To assess for pseudotumor, the anterior, medial, lateral, and posterior hip structures should be evaluated for joint and extra-articular fluid collections and soft tissue masses.29, 30 In patients with suggestive symptoms, ultrasound can provide guidance for diagnostic injections to assess for possible psoas tendon impingement. Specifications of a Knee Examination The examination of the knee is divided into four regions. The examination may involve an assessment of one or more of the four regions of the knee described below or may be limited to a specific anatomic structure, depending on the clinical presentation. Anterior The patient is supine with the knee flexed to 30°. Longitudinal and transverse scans of the quadriceps and patellar tendons, patellar retinacula, and suprapatellar recess are obtained. A portion of the distal femoral trochlear cartilage can be assessed with the transducer placed in the suprapatellar space in the transverse plane with the knee in maximal flexion. The prepatellar, superficial, and deep infrapatellar bursae are also evaluated using adequate gel to prevent inadvertent compression of the bursae by the transducer. Suprapatellar recess may be evaluated for detection of joint effusion. Medial During the ultrasound examination, the patient remains supine with slight flexion of the knee and hip and with slight external rotation of the hip. The medial collateral ligament, the pes anserine tendons and bursa, and the medial patellar retinaculum are scanned in both planes. The anterior horn and body of the medial meniscus may be identified in this position, particularly with valgus stress. If meniscal pathology is suspected either clinically or by ultrasound, further imaging with MRI is recommended. Alternatively, if there are contraindications to MRI, CT arthrography can be performed. Lateral The patient remains supine with the ipsilateral leg internally rotated. The popliteus tendon, biceps femoris tendon, fibular collateral ligament, and iliotibial band are scanned. The lateral patellar retinaculum can also be assessed in this position. The joint line is scanned for lateral meniscal pathology, with varus stress applied as needed. The common peroneal nerve can be localized in the popliteal fossa or identified posterior to the biceps femoris tendon and followed as it courses around the fibular neck. Posterior The patient lies prone with the leg extended. The popliteal fossa, semimembranosus muscle, medial and lateral gastrocnemius muscles, tendons, and bursae are assessed. To confirm the diagnosis of a popliteal cyst, the subgastrocnemius component of the semimembranosus-gastrocnemius bursa should be visualized between the medial head of the gastrocnemius and semimembranosus tendon. In addition, the posterior horns of both menisci may be evaluated. The tibial insertion of the posterior cruciate ligament may be identifiable in a sagittal oblique plane in this position.31, 32 Specifications of an Ankle Examination Ultrasound examination of the ankle is divided into four regions (anterior, medial, lateral, and posterior). The examination may involve an assessment of one or more of the four regions described below or be limited to a specific anatomic structure, depending on the clinical presentation. Anterior The anterior extensor tendons are assessed in long-axis and short-axis planes from their musculotendinous junctions to their distal insertions. From medial to lateral, this tendon group includes the tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius tendons (the latter being congenitally absent in some patients). The anterior joint recess is scanned for effusion, intra-articular bodies, synovial hypertrophy, and synovitis. The anterior joint capsule is attached to the anterior tibial margin and the neck of the talus. The hyaline cartilage of the talus appears as a thin hypoechoic line paralleling subchondral bone. Medial The tibialis posterior, flexor digitorum longus, and flexor hallucis longus tendons (located in this order from anterior to posterior) are