Page 326 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 301

VetBooks.ir 1.573 1.574

Fig. 1.574 Spontaneous rupture of the SDFT in
the carpal canal area. The DDFT is intact. The
SDFT is no longer visible, the space is filled by mixed
tissue consisting of blood, fibrin and tendon debris
Fig. 1.573 Subacute SDFT tear immediately distal
to the accessory carpal bone. Although a discrete (arrowheads). The synovial membrane is markedly
‘core’ lesion is visible (arrowheads), diffuse damage to thickened. Some fluid accumulates medially in
the tendon is present. Its contours are ill defined and the carpal sheath recess (cs). pcr = palmar carpal
blend into the thickened synovial membrane (arrows). retinaculum; mpa = medial palmar artery containing
pcr = palmar carpal retinaculum; ma = medial palmar a thrombus, a common occurrence in these cases;
artery. mn = median nerve (compressed).

Fig. 1.575 Transverse ultrasonogram of the SDFT 1.575
in the distal metacarpal area, within the digital
flexor tendon sheath. The SDFT is enlarged and
there is an irregular, peripheral hypoechogenic
lesion in the lateral part of the tendon (arrow).
The sheath is distended and a hypoechogenic halo
around the tendons suggests synovial inflammation
(tenosynovitis) (arrowhead).

Finally, injuries to the distal branches of the
SDFT near their insertion on the middle phalanx
are increasingly recognised. They may be restricted
to one or, rarely, to both branches, or extend proxi-
mally into the distal SDFT. The branch will gener-
ally appear enlarged, diffusely hypoechogenic and
heterogeneous (Fig. 1.576), although the lesion may
be well defined (Fig. 1.577). One or both branches
may be affected. There is usually associated digital
sheath effusion, particularly if the lesion extends as