Page 426 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.9 Muscle disorders of the horse 401

VetBooks.ir 1.769 1.770

Figs. 1.769, 1.770 Fibrotic and
ossifying myopathy. Transverse
(1.769) and longitudinal (1.770)
ultrasound scans of the distocaudal
thigh region showing loss of the
normal echostructure of the
semitendinosus muscle, which
appears echogenic and amorphous
(arrows) because of diffuse fibrosis.
The muscle contains hyperechogenic
areas casting acoustic shadowing
(arrowheads) characteristic of ectopic
mineralisation.

Management of the gait abnormality. More recently, tenotomy
In the acute stage, the muscle tear may be treated of the tendon of insertion of the semitendinosus
conservatively with rest, NSAIDs and local muscle on the tibial tuberosity under general anaes-
application of cold and massages. In the chronic, thesia has been recommended. This may require
established stages, surgical treatment is the only that a second incision is made over the common
option. Myotomy and myotenectomy (combined calcanean tendon to release the aponeurotic inser-
resection of a portion of muscle and tendon) have tion of the semitendinosus muscle.
been described, but both procedures are associated
with a high risk of complications (wound break- Prognosis
down, recurrence, worsening). Myotenectomy is The prognosis for complete resolution is guarded.
safer, but it may not provide complete resolution No improvement can be expected without surgery.

OTHER DISORDERS OF MUSCLES
Katie Snalune

CORYNEBACTERIUM abscesses, mainly in the pectoral and ventral abdomi-
PSEUDOTUBERCULOSIS ABSCESSES nal/inguinal regions, commonly called pigeon fever;
(2) internal infection causing visceral abscesses; and
Definition/overview (3) ulcerative lymphangitis, which results in limb
This is a condition characterised by spontaneously inflammation, cellulitis and severe lameness.
occurring intramuscular abscesses and muscle necro-
sis due to infection by C. pseudotuberculosis. In horses, Aetiology/pathophysiology
there are three clinical manifestations of C. pseudo- C. pseudotuberculosis is a gram-positive, faculta-
tuberculosis infection: (1) subcutaneous or muscular tive, intracellular, pleomorphic bacterium with a