158
46TH
ANNUAL
CONGRESS
OF
THE
SAEVA
SKUKUZA
16-‐20
FEBRUARY
2014
horses that have a lameness that has been localized to a specific region but
conventional diagnostic techniques such as radiographs and ultrasound have failed to
provide a definitive diagnosis. Diagnostic nerve blocks, especially of the foot region
can be confusing, and precise localization of the problem is often difficult. MRI can
help pinpoint pathology within the foot and provide excellent images of the soft
tissues within the foot that can be otherwise hard to obtain with radiographs and
ultrasound. In general terms, MRI is also helpful in providing additional information
on orthopaedic problems that have been identified, giving veterinarians better
information on treatment options and prognosis.
In recent literature there have been many publications describing pathology identified
with MR imaging in horses with lameness localized to the foot. These horses have
been documented to have a range of bone and/or soft tissue pathology, with many
having multiple abnormalities in this region.4-8 Specific pathology identified includes
degenerative changes in the navicular bone, impar ligament desmitis, deep digital
flexor tendonitis, lesions in the suspensory ligament of the navicular bone, navicular
bursa adhesions, flexor surface of the distal phalanx pathology, in addition to coffin
joint collateral ligament desmitis.4-12 MRI abnormalities associated with the palmar
process of the distal phalanx have also been described, the clinical significance of
which requires more investigation.13 Interpretation of classic navicular degenerative
changes has altered with the use of MRI. As an example, there is evidence
questioning whether distal border fragmentation is always a direct cause of pain in
horses.14-16 New information is also emerging regarding the significance of sidebones
(ossification of the collateral cartilages) and its association with collateral ligament of
the coffin joint desmitis or distal phalangeal injury.17
The abaxial sesamoid nerve block can result in analgesia of the fetlock region as well
as the pastern and foot in some instances and this must be considered when imaging
these animals. Interesting reports have documented lesions in the suspensory and
distal sesamoidean ligaments, collateral ligaments, intersesamoidean ligaments as well
as subchondral bone pathology that were not apparent on routine imaging using
radiology and ul