Page 101 - Adams and Stashak's Lameness in Horses, 7th Edition

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CHAPTER

Examination for Lameness

HISTORY, VISUAL EXAM, AND

CONFORMATION

Gary M. Baxter and ted S. StaShak

INTRODUCTION 3. Palpation of the musculoskeletal system including
hoof tester examination of the feet
Lameness is an indication of a structural or functional 4. Observation of the horse in motion (usually at a
disorder in one or more limbs or the axial skeleton that straight walk and trot/lope followed by circling)
is evident while the horse is standing or at movement. 5. Observation of the horse under saddle or in work if
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Lameness can be caused by trauma (single event or necessary
repetitive work), congenital or acquired anomalies, 6. Manipulative tests such as flexion tests
developmental defects, infection, metabolic distur­ 7. Diagnostic anesthesia if necessary
bances, circulatory and nervous disorders, or any com­ 8. Diagnostic imaging
bination of these. The diagnosis of lameness requires a
detailed knowledge of anatomy, an understanding of Palpation of the limbs and axial skeleton and hoof
kinetics and kinematics, and an appreciation for geo­ tester examination of the feet are usually performed
metric design and resultant forces. It is important to dif­ prior to exercising the horse. However, some clinicians
ferentiate between lameness resulting from pain and prefer to observe the horse at exercise prior to palpation
nonpainful alterations in gait, often referred to as of the musculoskeletal system. Diagnostic anesthesia
“mechanical lameness,” and lameness resulting from and imaging often follow to document the location of
neurologic (nervous system) dysfunction. 8,35 Lameness the pain, specific cause of the problem, extent of injury,
due to pain is most common in the horse. and prognosis for recovery.
A complete lameness examination helps to differenti­
ate among the many types of lameness problems in the
horse. The objectives of a lameness examination are to ADAPTIVE STRATEGIES OF LAME HORSES
determine:
Horses adapt to lameness with compensatory move­
1. Whether the horse is lame ments of specific body parts. 11,12,39 With most lameness
2. Which limb or limbs are involved conditions, the horse attempts to “unload” the lame limb
3. The site or sites of the problem during weight‐bearing or the stance phase of the stride.
4. The specific cause of the problem In a kinetic study of forelimb lameness, the vertical force
5. The appropriate treatment peak had the highest sensitivity and specificity for lame­
6. The prognosis for recovery ness classification. 12,24 Horses accomplish this by abnor­
mal movement of a body part (head nod or pelvic hike),
The steps to perform a routine or traditional lame­
ness examination include: weight shifting (to the contralateral or diagonal limb or
torso), change in joint angles (lack of fetlock extension),
1. Complete history including signalment and use and alterations in foot flight. For example, hyperexten­
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2. Visual exam of the horse at rest sion of the fetlock has been shown to be an indirect

Adams and Stashak’s Lameness in Horses, Seventh Edition. Edited by Gary M. Baxter.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.
Companion website: www.wiley.com/go/baxter/lameness
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