Equine Lameness for the Layman. G. Robert Grisel, DVM
commentary can be accessed directly on your smartphone by scanning the QR (“Quick Response”) code located within that aspect of the book’s narrative pertaining to the topic of interest. (There is also an index of video links and codes beginning on page 229.) Once you learn to recognize distinct patterns of movement, you’ll be able to distinguish between numerous forms of equine lameness.
Naturally, the intention is not to create a world in which horse owners are diagnosing lameness. A diagnosis is what we pay the veterinarian to provide for us. Rather, the information in this guidebook should be used to develop an appreciation and basic understanding of equine locomotion with the goal of being better prepared to recognize, classify, and rate your horse’s lameness when it occurs. The benefits associated with acquiring these basic skills will also be highlighted. Assessment will become especially fun and productive once you’ve learned to differentiate the nature and severity of what you’re seeing. You’ll be surprised at how much of the horse’s language you’re able to interpret. You’ll also be surprised to discover how much your horse has been trying to convey all of these years.
The information compiled in this book is based on personal experience. Observations have been developed and refined while performing approximately 30 equine lameness examinations per week over a 25-year period. Albeit the techniques described herein relate to horses, they could also be implemented to assist in the visual assessment of other quadrupeds and humans. Of course, they are most helpful when evaluating animals that can’t speak (verbally) to us.
Glossary
Throughout the pages ahead, you will find words in bold in the text. These highlighted words correspond with the definitions provided below. You can familiarize yourself with them now, or refer back as you come upon unfamiliar terms.
A
Abaxial: Away from the center of the body or limb.
Abduction: The movement of a body part away from the midline of the horse.
Acute: Of recent or abrupt onset. “This is an acute lameness; it just developed this morning.”
Adduction: The movement of a body part toward the midline of the horse.
Adhesion: The abnormal adherence of one anatomic structure to another.
Amphiarthrodial Joint: A fibrocartilagenous junction that allows limited motion between articulating bones.
Annular Ligament: A fibrous band that encircles the superficial and deep digital flexor tendons as they pass behind the fetlock joint and proximal sesamoid bones.
Anterior: Toward the front of the horse. More appropriately denoted as cranial. “The head is anterior to the neck.”
Appendicular: Refers to the limbs.
Arthritis: Joint inflammation.
Arthrotherapy: Treatment directed at improving joint health and function.
Artificial Gait: A gait that is either inspired through generations of breeding or learned through training.
Ascending Movement: Upward motion of one or more body parts.
Atrophy: Degeneration (or “wasting away”) of body tissue (e.g. muscle) due to lack of use or underlying pathology.
Axial: Toward the center of the body or limb.
Axial Lameness: Altered movement stemming from one or more structures associated with the axial skeleton. “Temporomandibular synovitis (TMJ), cervical arthrosis and ‘kissing spines’ all have the potential to generate axial lameness in the horse.”
Axial Skeleton: Consists of the horse’s head, vertebral column (within the neck, thorax, and lumbar regions), and sacrum.
B
Bar Shoe: Characterized by a closed (rather than open) heel.
Beat: The number of beats associated with a gait refers to the number of individual footfalls that occur before the sequence repeats. Two feet striking the ground surface simultaneously generate a single beat.
Bilateral Lameness: Altered movement manifesting on both (right and left) sides of the horse.
Biomechanical Lameness: Altered movement(s) made in an attempt to accommodate restricted or exaggerated action of one or more parts of the horse’s anatomy (usually the limbs). Many forms of biomechanical lameness have no inflammatory component and accordingly do not hurt.
Biomechanics: The structure and function of biological systems.
Breakover: The action of the hoof as it pivots over the toe to lift and move the respective limb forward.
Bursa: A synovial sack that facilitates tendon movement over bone via lubrication.
C
Caudal: Toward the tail. Refers to anatomy of the head and body parts above the carpi (knees) in the forelimbs and tarsi (hocks) in the hind limbs. “The pelvis is caudal to the neck.”
Centerline: An imaginary line that splits the horse into right and left halves (see also Midline).
Central Neurologic Lameness: Altered movement stemming from abnormal function of the brain and/or spinal column.
Cervicothoracic: The region adjoining the neck and chest.
Chronic: Of long or indefinite duration. “This horse has a chronic lameness; it first developed last year.”
Circumduction: The circular or conical movement of a limb relative to the horse’s body. During protraction, the circumducting limb moves away from the midline before moving back toward it, thus tracing a semicircle. This gait deficit is most often associated with neurologic disease in the horse.
Collagen Fibers: Small, inelastic reticular fibrils comprised of insoluble protein. Collagen fibers are found in skin, bone, ligaments, tendons, and cartilage, and comprise nearly one-third of all body protein.
Collateral: On either side. “The medial (inside) and lateral (outside) collateral ligaments of the fetlock joint function to maintain stability.”
Collection: A movement performed by the horse in which more weight is assumed by the hind limbs relative to the forelimbs.
Columnar: A pattern of muscle tissue in which individual fiber bundles (called fascicles) run parallel to the long axis of the structure and its respective tendon. This pattern allows for extensive range of motion but generates nominal force.
Compensating Limb: The limb that “takes the brunt” of the primary problem associated with another limb. “The horse’s left front limb often serves as the compensating limb for the right hind limb.”
Concentric Muscle Action: Contraction or shortening of muscle fibers.
Contraction: The process of becoming shorter or shrinking.
Contralateral: Located on the other side of the horse. “The right front limb is contralateral to the left front and left hind limbs.”
Contralateral