This document provides an overview of musculoskeletal ultrasound. It discusses the main indications for MSK ultrasound including pain, injury, arthritis and more. It describes the equipment used, including high frequency linear transducers of at least 7.5MHz. Proper probe placement and understanding anisotropy are important. The document outlines how different musculoskeletal tissues like muscle, tendons, ligaments, nerves, cartilage and bones appear on ultrasound. It provides details on anatomy and ultrasound characteristics of these various tissues.

1. MUSCULOSKELETAL ULTRASOUND
PRESENTED BY SYED YOUSAF FAROOQ

2. INDICATIONS
• Indications for MSK ultrasound include but are not limited to:
• 1. Pain or dysfunction.
• 2. Soft tissue or bone injury.
• 3. Tendon or ligament pathology.
• 4. Arthritis, synovitis, or crystal deposition disease.
• 5. Intra-articular bodies.
• 6. Joint effusion.
• 7. Nerve entrapment, injury, neuropathy, masses, or
subluxation.
• 8. Evaluation of soft tissue masses, swelling, or fluid
collections.

3. • 9. Detection of foreign bodies in the superficial soft
tissues.
• 10. Planning and guiding an invasive procedure. K.
Congenital or developmental anomalies.
• 11. Postoperative or post procedural evaluation
• An MSK ultrasound examination should be performed
when there is a valid medical reason.
• There are no absolute contraindications.
• Makes musculoskeletal sonography a powerful tool
for diagnosing abnormalities of the soft tissues.

4. EQUIPMENT SELECTION
• Musculoskeletal structures are long,
striated and many times layered tissues.
• Due to the striated morphology of these
tissues and their superficial location,
high frequency, linear array transducers
are best suited for this application.
• It is recommended that no less than 7.5
MHz transducers be used for
musculoskeletal examinations of the
extremities.

5. PROBE PLACEMENT
• It is very important to maintain accurate transducers
placement in musculoskeletal sonography.
• Due to the close proximity of several distinct structures in a
small area, a slight displacement of the probe can produce
inaccurate images.

6. ANISOTROPY
• Anisotropy is defined as the ability of a substance or material to
display different properties, depending on the angle of insonation

8. POSTERIOR ACOUSTIC SHADOWING

9. MUSCLE
• Muscle is made of bundles of contractile striated muscle fibers with their
major axis lying along the contraction direction.
• These muscle fibers have a considerable length, varying from a few
millimeters to several centimeters.

10. Muscle
• Muscle is externally
surrounded by a thick
connective sheath called
the epimysium.
• From the internal aspect of
this sheath several septa
invigilate to form the
perimysium, which
surrounds diverse bundles
of muscular fibers, named
fascicles
• Very light and thin septa
arising from the perymysium
spread into the fascicles to
surround every muscular
fiber and form the
endomysium.

11. PENNATION ANGLE
It is the angle measured between the muscular
fibers direction and the central Apo neurosis axis

12. SKELETAL MUSCLE
• On longitudinal views, the muscle septae appear as
echogenic structures, and are seen as thin bright linear
bands.

13. • On transverse views, the muscle bundles appear as
speckled echoes with short, curvilinear bright lines
dispersed throughout the hypoechoic background.

14. CORTICAL BONE
• On ultrasound examination, normal cortical bone
appears as a continuous echogenic (bright) line
with posterior acoustic shadowing (black).

15. TENDONS
• Transmit the muscular tension to mobile skeletal segments
• Extremely resistant to traction.
• Extremely variable shape and dimensions.
• Consist of about 70% of type I collagen fibers.

16. Tendon may either be:
Supporting
or
Sliding tendon

17. SLIDING TENDONS
SLIDING TENDONS are wrapped in a covering
sheath (tenosynovial sheath)
• Whose function is to guarantee better sliding
and protection to the tendons when they run
adjacent to irregular osseous surfaces, sites of
potential friction.

18. • In addition, US is the only
technique that allows the sonologist
to perform a dynamic study of
tendons, which is extremely
important for the diagnosis of
tendon pathology.

19. TENDONS
• In long axis view; the tendons
appear as echogenic ribbon-like
bands, defined by a marginal
hyperechoic line corresponding
to the paratenon and
characterized by a fibrillar
internal structure.
• On ultrasound the parallel series
of collagen fibers are
hyperechoic, separated by
hypoechoic surrounding
connective tissue.
• Tendons are known to be
anisotropic structures.

20. RETINACULUM
• Retinaculum is a transversal thickening of the deep fascia attached
to a bone’s eminence.
• The biomechanical function of a retinaculum is to keep the tendons
in position as they pass underneath it, in order to avoid their
dislocation during muscular action.

21. • Appear on ultrasound as
thin hyper echoic
structures located more
superficially than the
sliding tendons, in very
critical areas from a
biomechanical point of
view.
• Dynamic Scanning and
high amount of gel is
used as a spacer in order
to avoid any pressure on
the tissue, for the
evaluation of retinacula.

22. LIGAMENTS
• The structure of ligaments is very similar to that of tendons:
• The main differences are reduced thickness and a less
regular arrangement of structural elements; for this reason,
it is harder to study ligaments with US than tendons.

23. TYPES OF LIGAMENTS
• Intrinsic capsular ligaments
• Extrinsic ligaments

24. LIGAMENTS
Classified as;
• Extra-capsular ligaments
&
• Intra-capsular ligaments

25. ULTRASONOGRAPHY
• The US examination of ligaments, unlike tendons, is
mainly performed using long axis views, the transducer
being aligned on the ligament’s major axis.
• Transverse views (short axis) have poor diagnostic value.
With US, ligaments appear as homogeneous, hyper echoic
bands,
• 2-3 mm thick, lying close to the bone.

26. MOST COMMON LIGAMENTS
Ligaments of the medial and lateral
compartments of the ankle:
• Deltoid Ligament
• Anterior Talo-fibular Ligament
• Fibulo-calcaneal Ligament

27. MOST COMMON LIGAMENTS
• The collateral ligaments of the knee.
• The collateral and annular ligaments of the elbow.
• The coraco-acromial and coraco-humeral ligaments
of the shoulder.
• The ulnar collateral ligament of the thumb

28. THE LATERAL COMPARTMENT OF THE ANKLE.
THE ANTERIOR TALO-FIBULAR LIGAMENT

29. BURSAE
• In a normal joint, the bursa is a
thin black/ anechoic line no more
than 2 mm thick.
• The bursa fills with fluid due to
irritation or infection.

30. PERIPHERAL NERVES
• High-frequency transducers allow the
visualization of peripheral nerves that pass
close to the skin surface.

31. From an anatomical point of view, nerves are characterized by:
• A complex internal structure made of nervous fibers (containing
axons, myelin sheaths and Schwann cells) grouped to form
fascicles, and loose connective tissue (containing elastic fibers
and vessels)
PERIPHERAL NERVES

32. US provides advantages over MR imaging, including:
• A higher spatial resolution and the ability to explore long segments of
nerve trunks in a single study.
• To examine nerves in both static and dynamic states with real time
scanning.
• Systematic scanning on short axis planes is preferred to follow the
nerves contiguously throughout the limbs.

33. • On long axis
planes:
• Their appearance
is similar to
tendons, but less
echogenic.
• Nerves typically
appear as multiple
hypoechoic
parallel linear
areas separated
by hyperechoic

34. • On short axis planes:
• High-resolution US demonstrates nerves as
honeycomb appearance.
• Multiple, punctate echogenicities (bright dots)
within an ovoid, well-defined nerve sheath.

35. The outer boundaries of nerves are usually
undefined due to;
• Similar hyperechoic appearance of both the
superficial epineurium and the surrounding fat.

36. Nerves are compressible structures.
• Alter their shape depending on the volume of the
anatomical spaces within which they run,
• As well as on the bulk and conformation of the
perineural structures.

37. CARTILAGE
Ultrasound has great potential for the evaluation
of hyaline cartilage, as microscopic lesions could
be imaged by transducers with a high spatial
resolution.
Limited dimensions of acoustic windows
available for the visualization of the cartilage
surfaces.

38. • The most frequent artifacts in the examination of
cartilage profile is the angle of insonation.
• As in the examination of femoral trochlea which
is not totally perpendicular to the direction of the
US beam due to its wavy orientation.

40. CARTILAGINOUS CHANGES
These include:
• Loss of sharpness of the superficial margin
• Loss of transparency of the cartilaginous layer.
• Cartilage thinning and subchondral bone profile
irregularities.

41. Thank you