Page 236 - Adams and Stashak's Lameness in Horses, 7th Edition

202 Chapter 3

erosion (Figure 3.19), such as that seen with proliferative
synovitis in the metacarpophalangeal or metatar­
VetBooks.ir navicular bone are common and significant sites of
sophalangeal joints.
Cortical erosions seen on the flexor surface of the
disease. Flexor cortical erosive lesions most frequently
66
begin by affecting the palmar fibrocartilage and subse­
quently create bone erosion. However, it is also possi­
7
ble to have flexor cortical erosions as a result of pressure
resorption from dilated synovial invaginations, possi­
bly associated with distal interphalangeal synovitis,
which affect the endosteal surface and then extend pal­
marly. The palmoroproximal to palmorodistal oblique
46
(skyline) of the navicular bone is an essential radio­
graphic view to assess these types of lesions, should be
standard in the foot protocol, and may require several
varying angles to adequately assess the flexor surface
(Figure 3.20). 27
Cortical bone change is also associated with
enthesopathy and can be proliferative, resorptive, or
both. Joint capsule enthesopathies and the palmar liga­
ments of the pastern often are proliferative. Resorptive
lesions are more frequently found at the insertion of the
collateral ligaments on the distal phalanx (Figure 3.21)
and the insertion of the impar ligament on the flexor
surface of the distal phalanx. 10,65 The origin of the prox­
imal suspensory ligament on the third metacarpal/met­
atarsal (MCIII/MTIII) bones and the insertion of the
suspensory ligament branches on the sesamoid bones
often have mixed resorptive and proliferative
patterns. 19,55,57,60
Figure 3.16. Craniolateral to caudomedial oblique projection of
the tibia. A stress fracture of the tibia is present on the laterocaudal Cortical thickening is usually produced by increased
cortex of the mid‐diaphysis. Note the smooth, thickened periosteal weight bearing. Such changes in cortical width are fre­
reaction with a faint radiolucent cortical fracture line (arrow). A quently present with valgus or varus limb abnormalities
subtle endosteal reaction is also present at that level. Source: or as an adaptive response to exercise.
Courtesy of New Bolton Center, University of Pennsylvania.

A B

Figure 3.17. Examples of humeral (A) and tibial (B) stress fractures with only radiographic evidence of a periosteal reaction (arrows).
Source: Courtesy of New Bolton Center, University of Pennsylvania.