Page 330 - The Veterinary Care of the Horse

– it may be exacerbated when the affected limb is on the outside of a circle

– it often resolves rapidly with rest but recurs with hard work
VetBooks.ir – if the condition is bilateral, the horse may appear to move badly rather than look

lame

– with chronic lesions the horse may remain lame

– flexion of the distal limb accentuates the lameness in some but not all cases.
• Heat and slight swelling may be present in acute cases but neither are a consistent sign.

• Pain may be elicited on deep palpation of the origin of the ligament.

If the injury is severe, a fragment of cannon bone may become detached at the origin of the

ligament. This is known as an avulsion fracture. The lameness is usually unilateral, sudden in
onset and moderate to severe.

DIAGNOSIS

Because of the intermittent nature of the lameness and the lack of obvious heat and swelling,
the diagnosis is often confirmed using one or more of the following techniques.

Diagnostic analgesia

Nerve blocks are often used in order to confirm a diagnosis of proximal suspensory desmitis.
However, these have to be interpreted with care as they can eliminate other sources of pain

which may also be contributing to the lameness.

Ultrasonography

Good quality images are essential for diagnosis of this condition and monitoring of the
healing process. Both forelimbs are examined as the changes may be bilateral. Some injuries

show only very subtle ultrasongraphic changes and in unilateral cases comparison with the
other limb may be helpful.

Radiography

There are not usually any radiographic changes with acute proximal suspensory desmitis.
With a chronic injury, there may be increased bone density or new bone deposition at the top

of the cannon bone. When the lameness is sudden in onset and severe, radiography is used to
rule out an avulsion fracture of the cannon bone at the site of origin of the suspensory

ligament.