5
EQUINE MATTERS
RAD IOGRAPHY
Radiography
of the
equine foot
Paul Smith BVM&S CertEP MRCVS,
Westmorland Equine Vets
Veterinary surgeon
Paul Smith
XLEquine practice
Westmorland
Veterinary Group
The equine foot is one of, if not the, most common
areas of interest for radiographic evaluation.
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 1: Lateral view of the foot showing normal
alignment of pastern and pedal bones
Fig. 2: Dorsopalmar view of the foot showing
normal symmetry of the foot
Fig. 3: An unusual cause of foot pain. Barbed
wire stuck in a coronary band wound
Fig. 4: An example of poor mediolateral hoof
balance
Fig. 5: Poor hoof balance – a severely broken
back hoof pastern axis
Fig. 6: A case of laminitis showing rotation of the
pedal bone in relation to the hoof capsule
Foot pain is a major cause of equine
lameness and radiography is an important
diagnostic tool in identifying the location,
extent and severity of any injury or disease
within the foot. Its most important role is to
give information about bones and joints,
however, it can provide information about
soft tissues such as tendons and ligaments,
particularly where they attach to bone. Some
common causes of foot pain which may be
identified with the aid of radiography include
pedal bone fractures, osteomyelitis (infection
of the bone), osteoarthritis, laminitis and
navicular disease (Figures 3 and 6).
In the absence of lameness, radiographic
evaluation of the feet can also be used to
provide information about foot balance and
conformation. An animal which exhibits poor
foot conformation, imbalance or abnormal
patterns of growth will be at significantly
greater risk of developing lameness as a
result of abnormal forces on the bones and
soft tissues leading to injury. Consequently
radiography should be considered a powerful
tool, not only in the diagnosis, but also in
the prevention of lameness by providing
information about the specific farriery
requirements of an individual horse. Using
radiographs, vet and farrier can work together
as a team to maintain or improve a horse's
soundness and performance.
The widespread use of mobile digital x-ray
machines means that radiography of the feet
is a straightforward procedure but it can take
time to prepare and position the feet correctly
so as to avoid the need, risk and expense of
repeating images. Depending on the reasons
for taking the radiographs, removal of shoes
may or may not be necessary. For example,
performing radiographs with the shoes in
place can be useful when assessing foot
balance and conformation as they allow
accurate identification of the weight-bearing
surface and the position of the shoe in relation
to the hoof capsule and pedal bone.
However, if a source of lameness has been
localised to the foot, removal of the shoes
may be required to obtain the additional
views necessary to fully evaluate the foot.
Two views are usually required to fully assess
balance of the feet, one lateral (taken from
the side of the limb, see Figure 1) and one
dorsopalmar (taken from the front, see
Figure2). Bone alignment, heel and toe length
and sole depth can all be assessed on the
lateral radiograph with particular attention
being paid to the alignment of the pastern
and pedal bones and their relationship to the
hoof capsule, the so called ‘hoof pastern axis’.
A broken-back hoof pastern axis is a common
abnormality, particularly in warmbloods,
causing increased loading of the heels,
straining the deep digital flexor tendon and
supporting ligaments of the navicular bone
(Figure 5). The dorsopalmar view is used to
assess joint alignment, foot symmetry and the
length of both the medial (inner) and lateral
(outer) hoof walls (Figure 4). Excessive length
on either side can affect the rest of the limb
by causing uneven loading of joints, causing
stress on collateral ligaments or leading
to osteoarthritis.
Routine radiographic imaging of the foot can
be an invaluable aid to trimming, shoeing,
injury prevention, and treatment of injury,
whether the goal is to simply keep the horse
healthy and happy at pasture, or to facilitate
optimal performance of a competitive
equine athlete.
