Page 368 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.8 Soft-tissue injuries 343

VetBooks.ir 1.673 1.674

Figs. 1.673, 1.674
(1.673) Acute desmitis
of the AL-DDFT
(inferior check
ligament [ICL]).
A large, diffuse and
poorly delineated,
hypoechogenic lesion
is visible in the body
of the ICL (arrows).
(1.674) Longitudinal
(sagittal) scan of the
same horse.

1.675
Differential diagnosis
Mostly SL body desmitis and distension of the
carpal flexor sheath, as swelling occurs in the same
area; other causes of diffuse swelling of the palmar
metacarpus, including pathology in the distal limb
causing oedema and congestion of the palmar/
plantar veins. Rarely DDFT tendinopathy.

Diagnosis
Clinical examination
Suspicion should be based on swelling over the mid-
dle or proximal palmar metacarpus area, centred
between the flexor tendons and cannon, and more
prominent laterally. Pain is obvious on palpation and
on passive fetlock/carpal flexion.

Ultrasonography
Both palmar/plantar and lateral approaches should Fig. 1.675 A transverse scan from a lateral approach
be used to assess the ligament. Dynamic evalua- in the mid-metacarpal region. Subacute inferior check
tion (i.e. while flexing/extending the limb) helps to ligament (ICL) desmitis with a markedly enlarged ICL
detect adhesions and complete rupture. There is usu- with a mottled, heterogeneous echogenicity. (Arrows
ally markedly decreased echogenicity throughout denote margin of the ICL.)
the ligament and increased CSA of the AL-DDFT
(Figs. 1.673, 1.674). Discrete, hypoechogenic to parenchyma (Fig. 1.676). Lesions within the inferior
anechogenic lesions may be present, but a diffuse, very check ligament often occur in the middle section of
heterogeneous decrease in echogenicity is observed the ligament, but they may extend to the palmar car-
more commonly (Fig. 1.675). The AL-DDFT may pal ligament and/or to the DDFT. Distal lesions are
be near completely ruptured, with complete loss of occasionally encountered. There is usually secondary