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Musculoskeletal sonography has been useful in point-of-care patient management for many years. Recent technologic advances have brought these applications into mainstream patient care for providers in many fields.
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The superficial location of many musculoskeletal structures lends itself to detailed and accurate depiction of anatomic and pathologic conditions affecting the musculoskeletal system.
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Structures easily portrayed on musculoskeletal ultrasound (US) images include subcutaneous fat, muscle,
Bedside Musculoskeletal Ultrasonography
Section snippets
Key points
Probe selection
The key to obtaining useful information about most musculoskeletal pathology is using the highest frequency linear array transducer available. For most musculoskeletal imaging, an 8- to 14-MHz transducer should be used (Fig. 2).3
High-frequency transducers come in various shapes and footprints. Specialized transducers, such as the hockey stick footprint, can be useful during evaluation of smaller areas (Fig. 3).
Color flow or power Doppler imaging can be used to identify hyperemia or
Maximizing image quality
Patient and examiner comfort allow for the best images and most confident diagnosis with bedside US. Helping patients to settle into a comfortable position enhances their ability to cooperate with the scan. The sonographer should seek a relaxed hand position and grip on the probe. Resting the ulnar side of the hand on the patient and holding the transducer like a pencil allow for fine controlled movements to bring the area of interest into focus (Fig. 7). This also allows the examiner to use
Skin
Dermis and epidermis appear as a thin, linear echogenic stripe on US. In standard clinical settings, the two layers cannot be distinguished by US (Fig. 13).11
Subcutaneous Fat
Normal adipose tissue appears hypoechoic with thin, linear echogenic septations separating fat lobules. The septations generally run parallel to the overlying skin surface (Figs. 14 and 15).
Muscle
The morphology of normal muscle tissue is clearly evident on US. Multiple muscle fascicles are bundled together to form a muscle belly. A sheath called
Artifacts
Artifacts important in musculoskeletal sonography are consistent with those encountered in all other US imaging. One artifact that is uniquely important for imaging of tendons, however, is seldom an issue in other body parts. This artifact is called anisotropy and is related to the angle of the incident US beam.
When an ultrasound wave strikes the surface of a structure at a perpendicular angle, the normal tendon fibrillar pattern is well delineated. When the angle is not perpendicular, however,
Cellulitis
US appearance of cellulitis depends on severity and stage of infection. Initial findings are of overall thickening of the subcutaneous soft tissue, loss of normal architecture, and diffuse increase in echogenicity of skin and underlying adipose (Fig. 25). The linear septations that separate fat lobules become indistinct. This classic appearance of cellulitis is typically visualized within the first few days of the infection.17
The thickening and increased echogenicity of cellulitis seen on US is
Summary
Used as an extension of the physical examination, point-of-care bedside US can help facilitate diagnoses and aide in structuring management of many patients with musculoskeletal complaints and soft tissue abnormalities. US is often better than plain radiographs, CT, and MRI in evaluating some musculoskeletal complaints and is especially useful in assessing patients too unstable for transport or who are situated in resource-limited environments. The use of musculoskeletal ultrasonography will
References (35)
- et al.
Water bath evaluation technique for emergency ultrasound of painful superficial structures
Am J Emerg Med
(2004) - et al.
Lymph node sonography
Ultrasound Clin
(2011) - et al.
Musculoskeletal infections: ultrasound appearances
Clin Radiol
(2005) - et al.
Imaging of periosteal reactions associated with focal lesions of bone
Clin Radiol
(2005) - et al.
Bedside ultrasound evaluation of tendon injuries
Am J Emerg Med
(2012) - et al.
Non-neoplastic conditions presenting as soft tissue tumours
Clin Radiol
(2007) - et al.
A brief history of musculoskeletal ultrasound: “from bats and ships to babies and hips”
Rheumatology
(2004) - et al.
An evidence-based approach to emergency ultrasound
Emerg Med Pract
(2011) Fundamentals of musculoskeletal ultrasound
(2007)- et al.
Musculoskeletal sonography technique: focused versus comprehensive evaluation
AJR Am J Roentgenol
(2008)
The top 10 reasons musculoskeletal sonography is an important complementary or alternative technique to MRI
AJR Am J Roentgenol
(2008)
Musculoskeletal sonography: a dynamic tool for usual and unusual disorders
AJR Am J Roentgenol
(2007)
Detection of soft tissue hyperemia: value of power doppler sonography
AJR Am J Roentgenol
(1994)
Unexpected findings on point of care superficial ultrasound imaging before incision and drainage
J Ultrasound Med
(2011)
Extended field-of-view sonography in musculoskeletal imaging
J Ultrasound Med
(1991)
Common applications of dermatologic sonography
J Ultrasound Med
(2012)
Sonography of bone and bone-related diseases of the extremities
J Clin Ultrasound
(2004)
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