Page 314 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 289

VetBooks.ir 1.545 1.546

Figs. 1.545, 1.546 Podotrochlear bursography in a horse that sustained a puncture wound through the frog.
After placement of a needle in contact with the proximal part of the fibrocartilage (1.545), 5 ml of iodinated
contrast medium (iothalamate) are injected into the bursa (1.546). The medium not only fills the bursa (b) but
also the distal interphalangeal joint (j), indicating a probable fistula between the two cavities. There is leakage
of contrast medium in the soft tissues palmar to the DDFT (l).

Fig. 1.547 Electronic array transducers are most 1.547
commonly used for musculoskeletal applications.
(a) Linear array tranducer. This is the probe of choice
for most musculoskeletal applications in horses.
5–12 MHz probes are probably optimal for most
applications in equine medicine. (b) Microconvex
linear array transducer (pediatric abdominal).
Works at high frequencies (8–15 MHz) or mid-range
frequencies (5–12 MHz) and gives out a pie-shaped
image. Allows access to a wide area through a small
skin interface and over a broad range of angles, as the
probe may be tilted in relation to the skin. (c) Convex
linear array transducer. Similar to (b) but with a a b c
larger radius and usually working at lower frequencies
(2–6 MHz). Useful to image deeper areas covered by
large muscle masses (e.g. back or pelvis) or for the
abdomen.

of tendons and ligaments. It is also useful to assess structures or in horses with highly attenuating skin,
joint soft tissues, bone surfaces and all periarticu- such as cobs, ponies and draught horses.
lar structures. High-definition equipment is neces- The choice of the optimal probe will therefore
sary to accurately evaluate structures. Transducers depend not only on the location, size and depth of
working at 7.5 MHz or higher are generally adequate the structures to be assessed but also on the trans-
and the greater the frequency, the better the spatial mitting properties of the individual patient’s skin
resolution. Very high frequency beams (14 MHz or (Fig. 1.547). Linear array transducers (a) tend to
higher) are rapidly attenuated by superficial tissues be most practical in the distal limb. Curved array
and may not provide adequate imaging of deeper (microconvex or convex) transducers (b, c) will be