Fig. 4. Transverse ultrasound images (A, B) of the hind proximal suspensory ligament that were acquired with the horse resting on its toe. The beam was directed toward the plantar margin of the third metatarsal bone by use of on-angle (A) and off-angle (B) ultrasound beam orientations. C, Corresponding MR image at the same level. Note the adipose tissue and muscle bundles remain echogenic regardless of beam angle. Similar to that shown in Fig. 3, the ligament fibers are echogenic when the ultrasound beam is on-angle or perpendicular to the long axis of the tendon and are subsequently reduced in echogenicity when the ultrasound beam is off-angle. The peripheral margin of the ligament is visible when the ultrasound beam is off-angle.
Fig. 5. Probe position and resulting ultrasound images for angle contrast (on- and off-beam angles) ultrasound technique when imaging the proximal suspensory ligament in the forelimb. A, Ultrasound beam is perpendicular to the proximal suspensory ligament in the metacarpus. B, Corresponding transverse ultrasound image of the suspensory ligament by use of this perpendicular beam angle. C, Ultrasound beam is oblique incidence to the proximal suspensory ligament. A change in hand position with angle change is required to achieve this image. D, Corresponding transverse ultrasound image of the suspensory ligament with this off-angle technique. Note the hypoechogenicity in the ligament fibers of image D and the hyperechogenicity of the muscle and fat bundles in the suspensory ligament regardless of beam angle (B, D).
the ultrasonographer to appropriately adjust the machine and settings (transducer, frequency, depth,
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focal zones, and gain). In addition, altering the direction of the beam angle is necessary to assess
