Front Matter

Chapter 20 Imaging in Canine Sports Medicine 503

may be more subtle, and additional views
should always be considered.
For a more complete picture of a structure,
oblique views are often necessary. These views
include the dorso‐palmar/plantar medial to lat-
eral oblique (DPMLO) and dorso‐palmar/plantar
lateral to medial oblique (DPLMO). Since radiog-
raphy is a 2‐D image of a 3‐D structure, oblique
views will show surfaces obscured by superimpo-
sition. For example, in the foot the sesamoid bones
are difficult to evaluate in standard lateral and
dorso‐palmar/plantar views. However, on the
oblique views the sesamoids can be viewed more
clearly for identification of pathological changes.
Other unique views have been described to
fully evaluate specific abnormalities. For exam-
ple, in the shoulder, a skyline or tangential view
will help visualize the intertubercular groove of
the humerus and differentiate supraspinatus
and biceps tendon mineralization (Flo &
Middleton, 1990) (Figure 20.1). Osteochondritis
dissecans lesions on the lateral trochlear ridge
of the talus are best viewed on the flexed sky-
line and dorsomedial palmar lateral oblique
(DMPLO) images (Gielen et al., 2005).
Joint stressed views can also provide critical
information as to the nature of soft tissue injury
to the supporting structures of the joint. At rest
or in recumbency, sub‐ or complete luxations
may not be visible radiographically, but when
stress is applied to the joint, luxations may
become apparent. Stressed views can also help
determine the degree of instability in the joint,
which can be helpful in determining a treat-
ment plan. Often more subtle than luxations,

are injuries to the collateral ligaments of the

joints. Collateral ligaments exist as medial and

lateral supporting structures in almost every

joint of the limbs. Medial and lateral stressed

views can be very important in determining

collateral ligament injury and joint stability.

Stressed views are also useful to evaluate joint

angles. These views put the joint of interest in

weight‐bearing position to determine whether the

supporting structures are normal. This is most

effectively done by taking the radiograph in stand-

ing position, which is common in equine practice.

It is more difficult to achieve in small animal prac-

tice due to the X‐ray tube head being fixed to the

radiographic table. When it is not possible to take

the radiograph in a standing position, weight

bearing can be simulated by putting the limb in

stance position with pressure applied to mimic

body‐weight. Evaluation of carpal hyperextension

frequently uses stressed views to determine the

joint level of the injury and the subsequent treat-

ment options (Piermattei et al., 2006).

Computed tomography

Computed tomography (CT) is a complex X‐ray

modality that creates multiplanar 2‐D cross‐

sectional images. (Figure 20.2). This allows for

Figure 20.1 Skyline view of the shoulder joint. This
view allows better visualization of the bicipital groove
and the region of insertion of the supraspinatus tendon
on the greater tubercle. Mineralization and remodeling
of the greater tubercle of the humerus is present in this
image associated with a supraspinatus tendinopathy
(arrow).

Figure 20.2 CT image of a cross‐sectional slice through

the elbow joint. The arrow indicates a fragmented

coronoid process. Source: Image courtesy of Toby

Gemmill, Willows Referral Service, UK.