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Basics of musculoskeletal ultrasonography
/content/chapter/10.22233/9781910443293.chap2
Basics of musculoskeletal ultrasonography
- Authors: Nele Ondreka and Martin Kramer
- From: BSAVA Manual of Canine and Feline Musculoskeletal Imaging
- Item: Chapter 2, pp 15 - 27
- DOI: 10.22233/9781910443293.2
- Copyright: © 2016 British Small Animal Veterinary Association
- Publication Date: January 2016
Abstract
Ultrasonography has become a routine part of the diagnostic work-up in patients with musculoskeletal pathologies. Recent equipment and software developments such as transducer design, compound imaging, harmonic imaging and signal post-processing have led to substantial improvements in image quality. These advances have expanded the range of applications beyond muscle and tendon pathology to numerous smaller structures such as ligaments and peripheral nerves. This chapter explains the indications for and value of ultrasonography compared with radiography and advanced imaging techniques; equipment; ultrasound examination; normal ultrasonographic anatomy; ultrasonographic abnormalities; interventional procedures. The chapter also includes three video clips.
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Figures
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2.1
(a) Longitudinal image of the normal infraspinatus (IS) and deltoideus (D) muscles. Linear hyperechoic striations are regularly distributed within a hypoechoic background. A linear hyperechoic fascial band demarcates the border between the muscle bellies (arrowed). (b) Transverse image of the normal supraspinatus muscle. Multiple hyperechoic foci are visible within the hypoechoic background. Note the evenly hyperechoic bone surface of the infraspinatus fossa (arrowheads) with complete distal shadowing in both images (a) and (b). © 2016 British Small Animal Veterinary Association
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2.1
(a) Longitudinal image of the normal infraspinatus (IS) and deltoideus (D) muscles. Linear hyperechoic striations are regularly distributed within a hypoechoic background. A linear hyperechoic fascial band demarcates the border between the muscle bellies (arrowed). (b) Transverse image of the normal supraspinatus muscle. Multiple hyperechoic foci are visible within the hypoechoic background. Note the evenly hyperechoic bone surface of the infraspinatus fossa (arrowheads) with complete distal shadowing in both images (a) and (b).
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2.2
Longitudinal image of the soft tissues in the axillary region. The cutis (arrowed) is a homogeneously echogenic band parallel to the transducer surface. The subcutaneous fat is hypoechoic with linear hyperechoic bands (between arrowheads). Deep to the subcutaneous fat the pectoralis muscle (PM) is seen. © 2016 British Small Animal Veterinary Association
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2.2
Longitudinal image of the soft tissues in the axillary region. The cutis (arrowed) is a homogeneously echogenic band parallel to the transducer surface. The subcutaneous fat is hypoechoic with linear hyperechoic bands (between arrowheads). Deep to the subcutaneous fat the pectoralis muscle (PM) is seen.
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2.3
(a) Longitudinal image of the normal infraspinatus tendon inserting distal to the major tubercle (MT). Proximal is to the left. The tendon is composed of multiple parallel hyperechoic fibres and a fine hyperechoic peritendon (arrowheads). Note the decreasing echogenicity and visibility of the fibrillar pattern with non-perpendicular incidence of the ultrasound beam (arrowed). (b) Transverse image of the normal superficial digital flexor tendon (SF) and gastrocnemius tendon (G) superficial to the calcaneal tubercle (CT). Densely packed hyperechoic foci are surrounded by a fine echogenic peritendineum (arrowed) separating the tendons. © 2016 British Small Animal Veterinary Association
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2.3
(a) Longitudinal image of the normal infraspinatus tendon inserting distal to the major tubercle (MT). Proximal is to the left. The tendon is composed of multiple parallel hyperechoic fibres and a fine hyperechoic peritendon (arrowheads). Note the decreasing echogenicity and visibility of the fibrillar pattern with non-perpendicular incidence of the ultrasound beam (arrowed). (b) Transverse image of the normal superficial digital flexor tendon (SF) and gastrocnemius tendon (G) superficial to the calcaneal tubercle (CT). Densely packed hyperechoic foci are surrounded by a fine echogenic peritendineum (arrowed) separating the tendons.
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2.4
Longitudinal image of the normal supraspinatus tendon. Proximal to the insertion the tendon exhibits a characteristic hyperechoic fibrillar pattern (arrowheads). Closer to the insertion at the major tubercle (MT) of the humerus the supraspinatus tendon widens and exhibits a mixed echo pattern due to fibre divergence (arrowed). The supraglenoid tubercle of the scapula (S) is visible deep to the supraspinatus tendon. © 2016 British Small Animal Veterinary Association
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2.4
Longitudinal image of the normal supraspinatus tendon. Proximal to the insertion the tendon exhibits a characteristic hyperechoic fibrillar pattern (arrowheads). Closer to the insertion at the major tubercle (MT) of the humerus the supraspinatus tendon widens and exhibits a mixed echo pattern due to fibre divergence (arrowed). The supraglenoid tubercle of the scapula (S) is visible deep to the supraspinatus tendon.
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2.5
Longitudinal image of the normal elbow joint collateral ligament obtained using a medial approach. A small amount of synovial fluid (S) is visible in the area of the joint space. The joint capsule and medial collateral ligament (arrowheads) are represented by a well delineated layered structure of medium echogenicity bridging the joint space from the distal aspect of the humerus (H) to the proximal aspect of the ulna (U). © 2016 British Small Animal Veterinary Association
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2.5
Longitudinal image of the normal elbow joint collateral ligament obtained using a medial approach. A small amount of synovial fluid (S) is visible in the area of the joint space. The joint capsule and medial collateral ligament (arrowheads) are represented by a well delineated layered structure of medium echogenicity bridging the joint space from the distal aspect of the humerus (H) to the proximal aspect of the ulna (U).
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2.6
Longitudinal image of the femoral diaphysis. The bone surface (arrowheads) is smooth, hyperechoic and exhibits complete acoustic shadowing deep to the surface. © 2016 British Small Animal Veterinary Association
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2.6
Longitudinal image of the femoral diaphysis. The bone surface (arrowheads) is smooth, hyperechoic and exhibits complete acoustic shadowing deep to the surface.
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2.7
Longitudinal image of the normal elbow obtained using a medial approach. Protrusions of the bone at the level of tendinous entheses such as the flexor tendon origin (FT) at the medial humeral epicondyle (ME) create an uneven, yet smooth, surface with complete acoustic shadowing. Distal to the musculotendinous junction, the echogenicity of the flexor muscles (FM) decreases. The outline of the surface of the ulna (U) is indistinct owing to non-perpendicular insonation. © 2016 British Small Animal Veterinary Association
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2.7
Longitudinal image of the normal elbow obtained using a medial approach. Protrusions of the bone at the level of tendinous entheses such as the flexor tendon origin (FT) at the medial humeral epicondyle (ME) create an uneven, yet smooth, surface with complete acoustic shadowing. Distal to the musculotendinous junction, the echogenicity of the flexor muscles (FM) decreases. The outline of the surface of the ulna (U) is indistinct owing to non-perpendicular insonation.
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2.8
Longitudinal image of the normal femoral condyle (FC). A thin layer of anechoic joint cartilage is visible superficial to the hyperechoic subchondral bone surface. With perpendicular insonation the cartilage surface is demarcated by a fine hyperechoic specular surface reflection (arrowhead). © 2016 British Small Animal Veterinary Association
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2.8
Longitudinal image of the normal femoral condyle (FC). A thin layer of anechoic joint cartilage is visible superficial to the hyperechoic subchondral bone surface. With perpendicular insonation the cartilage surface is demarcated by a fine hyperechoic specular surface reflection (arrowhead).
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2.9
(a) Longitudinal image of the normal sciatic nerve (arrowheads) between the biceps femoris (BF) and adductor (A) muscles parallel to the proximal femur. Regular hypoechoic internal echoes are surrounded by a strikingly hyperechoic nerve sheath. (b) Transverse image of the normal sciatic nerve between the biceps femoris (BF), semitendinosus (ST), semimembranosus (SM) and adductor (A) muscles at the level of the proximal femur. The sciatic nerve is composed of the bigger tibial (arrowhead) and smaller peroneal (arrowed) nerves – both are visible as round hypoechoic structures with a highly reflective sheath. © 2016 British Small Animal Veterinary Association
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2.9
(a) Longitudinal image of the normal sciatic nerve (arrowheads) between the biceps femoris (BF) and adductor (A) muscles parallel to the proximal femur. Regular hypoechoic internal echoes are surrounded by a strikingly hyperechoic nerve sheath. (b) Transverse image of the normal sciatic nerve between the biceps femoris (BF), semitendinosus (ST), semimembranosus (SM) and adductor (A) muscles at the level of the proximal femur. The sciatic nerve is composed of the bigger tibial (arrowhead) and smaller peroneal (arrowed) nerves – both are visible as round hypoechoic structures with a highly reflective sheath.
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2.10
Transverse image of the caudal aspect of the stifle of a dog with subcutaneous cellulitis. Multiple hyperechoic fat lobules of varying size and shape are separated by hypoechoic fluid layers, resulting in a cobblestone appearance. A muscle belly (M) in cross-section is visible next to the area of cellulitis. © 2016 British Small Animal Veterinary Association
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2.10
Transverse image of the caudal aspect of the stifle of a dog with subcutaneous cellulitis. Multiple hyperechoic fat lobules of varying size and shape are separated by hypoechoic fluid layers, resulting in a cobblestone appearance. A muscle belly (M) in cross-section is visible next to the area of cellulitis.
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2.11
(a) Longitudinal image of a subcutaneous mast cell tumour with central necrosis. The tumour is well circumscribed and of mixed echogenicity with an echogenic periphery and anechoic centre. (b) The power Doppler examination demonstrates moderate vascularization of the periphery and lack of vessels in the lesion centre consistent with tumour necrosis. © 2016 British Small Animal Veterinary Association
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2.11
(a) Longitudinal image of a subcutaneous mast cell tumour with central necrosis. The tumour is well circumscribed and of mixed echogenicity with an echogenic periphery and anechoic centre. (b) The power Doppler examination demonstrates moderate vascularization of the periphery and lack of vessels in the lesion centre consistent with tumour necrosis.
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2.12
(a) Large subcutaneous mass in the ventral neck region, histologically diagnosed as a paraganglioma originating from the carotid bodies. The mass is complex, with irregular hypoechoic to anechoic zones and hyperechoic regions with shadowing indicating calcification. (b) A high degree of vascularization is demonstrated in the colour Doppler examination. Most of the anechoic lesions seen in the greyscale image represent large tumour vessels. © 2016 British Small Animal Veterinary Association
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2.12
(a) Large subcutaneous mass in the ventral neck region, histologically diagnosed as a paraganglioma originating from the carotid bodies. The mass is complex, with irregular hypoechoic to anechoic zones and hyperechoic regions with shadowing indicating calcification. (b) A high degree of vascularization is demonstrated in the colour Doppler examination. Most of the anechoic lesions seen in the greyscale image represent large tumour vessels.
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2.13
Subcutaneous lipoma in the thoracic wall represented by a well circumscribed ovoid hypoechoic mass with multiple fine hyperechoic striations. © 2016 British Small Animal Veterinary Association
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2.13
Subcutaneous lipoma in the thoracic wall represented by a well circumscribed ovoid hypoechoic mass with multiple fine hyperechoic striations.
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2.14
Large infiltrative liposarcoma in the dorsal neck region. The tumour margins cannot be distinguished from the surrounding normal tissue. Only part of the lesion exhibits the typical ultrasonographic features of a lipoma (*). Large parts of the tumour are composed of complex hyperechoic regions (arrowheads). © 2016 British Small Animal Veterinary Association
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2.14
Large infiltrative liposarcoma in the dorsal neck region. The tumour margins cannot be distinguished from the surrounding normal tissue. Only part of the lesion exhibits the typical ultrasonographic features of a lipoma (*). Large parts of the tumour are composed of complex hyperechoic regions (arrowheads).
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2.15
Fresh subcutaneous haematoma in the thoracic wall superficial to a rib (R). The homogeneously anechoic haemorrhage distributes between thin hyperechoic layers of subcutaneous tissue. © 2016 British Small Animal Veterinary Association
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2.15
Fresh subcutaneous haematoma in the thoracic wall superficial to a rib (R). The homogeneously anechoic haemorrhage distributes between thin hyperechoic layers of subcutaneous tissue.
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2.16
Old haematoma with clot retraction and liquefaction as demonstrated by a predominantly anechoic content. Note the well defined echogenic wall and septations within the centre of the haematoma, representing the clot. © 2016 British Small Animal Veterinary Association
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2.16
Old haematoma with clot retraction and liquefaction as demonstrated by a predominantly anechoic content. Note the well defined echogenic wall and septations within the centre of the haematoma, representing the clot.
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2.17
(a) Typical ultrasonographic appearance of an abscess with a thick hyperechoic slightly irregular wall. Hyperechoic septations and scattered echogenic content are visible in the lesion centre. The abscess is located caudoventral to the mandible (M). (b) The centre of the lesion is non-vascularized, as demonstrated with power Doppler. © 2016 British Small Animal Veterinary Association
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2.17
(a) Typical ultrasonographic appearance of an abscess with a thick hyperechoic slightly irregular wall. Hyperechoic septations and scattered echogenic content are visible in the lesion centre. The abscess is located caudoventral to the mandible (M). (b) The centre of the lesion is non-vascularized, as demonstrated with power Doppler.
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2.18
Abscesses with different foreign bodies surrounded by multiple floating internal echoes. (a) A wooden foreign body in the centre of the abscess is represented by a hyperechoic surface with distal acoustic shadowing. (b) The grass awn in the centre of the abscess is visible as a well defined spindle-shaped structure with two echogenic interfaces. Acoustic shadowing is not present. © 2016 British Small Animal Veterinary Association
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2.18
Abscesses with different foreign bodies surrounded by multiple floating internal echoes. (a) A wooden foreign body in the centre of the abscess is represented by a hyperechoic surface with distal acoustic shadowing. (b) The grass awn in the centre of the abscess is visible as a well defined spindle-shaped structure with two echogenic interfaces. Acoustic shadowing is not present.
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2.19
Longitudinal image of the thoracic wall showing recent complete rupture of the serratus ventralis muscle. The gap between the thickened proximal (arrowhead) and distal (arrowed) stumps is filled with an anechoic haematoma (*). © 2016 British Small Animal Veterinary Association
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2.19
Longitudinal image of the thoracic wall showing recent complete rupture of the serratus ventralis muscle. The gap between the thickened proximal (arrowhead) and distal (arrowed) stumps is filled with an anechoic haematoma (*).
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2.20
Longitudinal image of a complete rupture of the patellar tendon. The proximal (arrowed) and distal (arrowheads) tendon stumps broaden towards the site of rupture, which is indicated by an anechoic haematoma. The regular fibre pattern of the tendon is completely interrupted. F = femur; T = tibia. © 2016 British Small Animal Veterinary Association
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2.20
Longitudinal image of a complete rupture of the patellar tendon. The proximal (arrowed) and distal (arrowheads) tendon stumps broaden towards the site of rupture, which is indicated by an anechoic haematoma. The regular fibre pattern of the tendon is completely interrupted. F = femur; T = tibia.
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2.21
Longitudinal image of the supraspinatus tendon with calcifying tendinopathy. An ovoid hyperechoic focus of calcification with irregular surface and acoustic shadowing is visible within the supraspinatus tendon (arrowheads) close to the insertion on the major tubercle (MT). © 2016 British Small Animal Veterinary Association
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2.21
Longitudinal image of the supraspinatus tendon with calcifying tendinopathy. An ovoid hyperechoic focus of calcification with irregular surface and acoustic shadowing is visible within the supraspinatus tendon (arrowheads) close to the insertion on the major tubercle (MT).
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2.22
Transverse (a) and longitudinal (b) images of biceps tenosynovitis. (a) The tendon sheath is severely thickened and prominent (arrowheads). A small amount of anechoic effusion can be seen within the tendon sheath. A semicircular concave exostosis (arrowed) is present within the bicipital groove (BG) deep to the tendon. The biceps tendon shows a slightly irregular outline and hypo- and hyperechoic foci. (b) The anechoic effusion within the tendon sheath (arrowheads) is better appreciated in the longitudinal plane in this case. © 2016 British Small Animal Veterinary Association
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2.22
Transverse (a) and longitudinal (b) images of biceps tenosynovitis. (a) The tendon sheath is severely thickened and prominent (arrowheads). A small amount of anechoic effusion can be seen within the tendon sheath. A semicircular concave exostosis (arrowed) is present within the bicipital groove (BG) deep to the tendon. The biceps tendon shows a slightly irregular outline and hypo- and hyperechoic foci. (b) The anechoic effusion within the tendon sheath (arrowheads) is better appreciated in the longitudinal plane in this case.
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2.23
Longitudinal images of a mid-diaphyseal tibial fracture immediately (a) and 10 days (b) after trauma. (a) The smooth hyperechoic bone surface is interrupted at the level of the fracture. A small anechoic haematoma is visible in the fracture area. A significant amount of periosteal vascularization cannot be demonstrated with power Doppler. Flow within one larger vessel outside the periosteal haematoma is indicated in the Doppler map. (b) Ten days after the trauma, non-mineralized periosteal callus (arrowheads) can be seen superficial to the bone surface. There is a significant amount of periosteal vascularization indicating normal bone healing. The fracture area is still prominent. © 2016 British Small Animal Veterinary Association
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2.23
Longitudinal images of a mid-diaphyseal tibial fracture immediately (a) and 10 days (b) after trauma. (a) The smooth hyperechoic bone surface is interrupted at the level of the fracture. A small anechoic haematoma is visible in the fracture area. A significant amount of periosteal vascularization cannot be demonstrated with power Doppler. Flow within one larger vessel outside the periosteal haematoma is indicated in the Doppler map. (b) Ten days after the trauma, non-mineralized periosteal callus (arrowheads) can be seen superficial to the bone surface. There is a significant amount of periosteal vascularization indicating normal bone healing. The fracture area is still prominent.
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2.24
Longitudinal image of an osteosarcoma within the distal femoral metaphysis. Cortical destruction and periosteal reactions are represented by a highly irregular bone surface with multiple interruptions (arrowheads). Note the large heterogeneous soft tissue component (arrowed) of the tumour extending beyond the bone surface which is readily accessible for ultrasound-guided sampling. © 2016 British Small Animal Veterinary Association
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2.24
Longitudinal image of an osteosarcoma within the distal femoral metaphysis. Cortical destruction and periosteal reactions are represented by a highly irregular bone surface with multiple interruptions (arrowheads). Note the large heterogeneous soft tissue component (arrowed) of the tumour extending beyond the bone surface which is readily accessible for ultrasound-guided sampling.
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2.25
Stifle joint with osteochondritis dissecans of the lateral femoral condyle. (a) Longitudinal infrapatellar image of the lateral femoral condyle (FC) and tibia (T). The joint surface defect (arrowhead) is seen as a focal interruption of the cartilage layer with surface irregularity and increased echogenicity superficial to a depression within the subchondral bone. Hyperechoic foci in the usually anechoic cartilage layer at the base of the defect represent small cartilage fragments. A small amount of anechoic effusion is visible adjacent to the osteochondrotic lesion. (b) Transverse image of the same stifle joint using a caudal approach with the joint extended. A well defined hyperechoic structure (arrowhead) with acoustic shadowing, representing a mineralized joint mouse, is visible caudal to the femur (F) within the caudoproximal extension of the stifle joint (arrowed). © 2016 British Small Animal Veterinary Association
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2.25
Stifle joint with osteochondritis dissecans of the lateral femoral condyle. (a) Longitudinal infrapatellar image of the lateral femoral condyle (FC) and tibia (T). The joint surface defect (arrowhead) is seen as a focal interruption of the cartilage layer with surface irregularity and increased echogenicity superficial to a depression within the subchondral bone. Hyperechoic foci in the usually anechoic cartilage layer at the base of the defect represent small cartilage fragments. A small amount of anechoic effusion is visible adjacent to the osteochondrotic lesion. (b) Transverse image of the same stifle joint using a caudal approach with the joint extended. A well defined hyperechoic structure (arrowhead) with acoustic shadowing, representing a mineralized joint mouse, is visible caudal to the femur (F) within the caudoproximal extension of the stifle joint (arrowed).
Supplements
Subcutaneous cellulitis with a grass awn in longitudinal section.
The grass awn is represented by a hyperechoic spindle-shaped structure with two echogenic interfaces and mild acoustic shadowing. The surrounding subcutaneous tissue comprises multiple hyperechoic fat lobules separated by hypoechoic fluid-filled interspaces.
Subcutaneous cellulitis with a grass awn in transverse section.
The short axis of the grass awn comprises two echogenic interfaces with mild acoustic shadowing and is hard to identify.
Avulsion fracture of the supraglenoid tubercle in a young dog.
The supraglenoid tubercle of the scapula is visible in the mid aspect of the image between the scapula to the left and the humerus to the right. Distal displacement of the supraglenoid tubercle upon flexion of the shoulder joint is indicated by increased distance between the scapula and its supraglenoid tubercle. The gap is filled with hypoechoic fluid.