Page 62 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.2 The foal and developing animal 37

VetBooks.ir 1.65 1.66

Fig. 1.65 Older weanling Thoroughbred-type foal Fig. 1.66 Premature foal with gross hypoplasia of the
with tarsal valgus due to collapse of small tarsal bones tarsal bones with obvious wedging of the central and
in a medial to lateral plane as a young foal. third tarsal bones. (Photo courtesy Graham Munroe)

CONGENITAL FLEXURAL Clinical examination
LIMB DEFORMITIES Clinical examination should include careful palpation
and manipulation of the affected joint(s) in a weight-
Definition/overview bearing and non-weight-bearing position. This condi-
Congenital flexural limb deformities by definition tion mainly affects the fetlock joint of newborn foals
are present at birth and are of unknown aetiology. and, less commonly, the DIP joint. The hindlimbs are
Possible causes have been suggested and include affected as, or more, commonly than the forelimbs.
intrauterine malpositioning, toxic insults during Palpation of the flexor tendons, suspensory ligament
embryonic life (e.g. maternal ingestion of locoweed and inferior check ligament may further indicate
or hybrid Sudan grass), genetic factors, influenza those structures involved. Radiographic examination
virus infecting pregnant mares, dams fed goitro- of affected joints is useful to determine the presence
genic diets and neuromuscular disorders. They are of specific bone or joint abnormalities, which may
not due to ‘contracted tendons’, but to a relative affect the prognosis of the case.
shortening of a musculotendinous unit in relation to Such deformities are usually effectively managed
bony structures. using a proprietary splinting system or by creating a