Page 149 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition
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124 CHAPTER 1
VetBooks.ir 1.4 The forelimb
Examination of the horse or pony with the appropriate use of imaging modalities are
forelimb lameness is a common undertaking in important in allowing an accurate diagnosis
equine practice. Many clinicians find forelimb to be made in the majority of cases. Some
lameness easier to recognise and work on conditions are particular to the type of
but, as always in lameness diagnosis, careful horse encountered (e.g. young racehorses),
history taking, detailed clinical examination, but many forelimb conditions are seen in all
the use of diagnostic analgesia techniques and types of horse.
PASTERN
FRACTURES OF THE PROXIMAL complete transverse (Fig. 1.218). Osteochondral
AND MIDDLE PHALANGES fragmentation and palmar/plantar eminence P1
fractures are covered in the section on the fetlock.
Definition/overview Fractures of the middle phalanx (P2) include
Fractures of the proximal phalanx (P1) can be sagittal osteochondral fragmentation of the palmar/plan-
(incomplete or complete) (Figs. 1.214–1.216), dor- tar aspect of the pastern joint, uniaxial fractures
sal frontal, comminuted (Fig. 1.217) or, more rarely, of the palmar/plantar eminence (Fig. 1.219),
biaxial eminence fractures, comminuted fractures
(Figs. 1.220, 1.221) and, less commonly, oblique or
1.214 transverse fractures.
Aetiology/pathophysiology
P1 fractures are one of the most common fractures in
racehorses. Classically seen as a single-impact injury,
there is increasing evidence that prodromal changes
may occur before development of a fulminant injury.
P1 fractures can also occur in other types at pasture
or undergoing other athletic activities.
Sagittal P1 fractures usually start at the proximal
articular surface of the bone, extending in a distal
direction of variable length with short incomplete
(<30 mm), long incomplete (>30 mm) and complete
sagittal fractures described. Complete fractures may
either exit through the lateral cortex or extend to the
proximal interphalangeal (PIP) joint ( biarticular).
Fractures in the frontal plane start at the proxi-
mal articular surface, extending distally and can be
incomplete or complete with varying degrees of dis-
placement. Comminuted P1 fractures may present
with or without an intact strut of bone and be vari-
ably comminuted (≥3 pieces).
Fig. 1.214 An incomplete short sagittal P1 fracture Comminuted or palmar/plantar eminence P2
just lateral to the sagittal groove. fractures generally occur due to an acute traumatic
