Equine Lameness for the Layman. G. Robert Grisel, DVM
The comparable limb located on the other side of the horse. “The right hind limb is the contralateral counterpart to the left hind limb.”
Contralateral Limb: A limb located on the other side of the horse. “The left front limb is contralateral to the right front and right hind limbs.”
Correct Lead: Leading with the inside forelimb while turning or circling.
Cranial: Toward the head. Refers to body parts above the carpi (knees) in the forelimbs and tarsi (hocks) in the hind limbs. “The neck is cranial to the pelvis.”
Cross-Firing: Striking the forelimb with the opposite (diagonal) hind foot. Occurs in pacers.
D
Daisy Cutter: A horse that demonstrates a flat stride with very little elevation of the limbs during protraction.
Descending Movement: Downward motion of one or more body parts.
Desmitis: Inflammation of ligament tissue.
Desmopathy: Ligament disease.
Diagonal Gait: A method of movement in which the forelimb and hind limb on opposite sides of the horse mimic each other in action.
Diagonal Pair: The pair of limbs that mirror each other in action. “The left hind and right front limbs comprise one diagonal pair and the right hind and left front limbs comprise the other.”
Diarthrodial Joint: A freely-movable joint characterized by the presence of a fibrous capsule, synovial membrane, lubricating (synovial) fluid and fibro- or hyaline cartilage layers which line opposing bony surfaces.
Differential List: A distinguishing list of diseases or conditions that present similar symptoms or clinical signs.
Distal: Toward the free (lower) end of the limb. “The foot is distal to the fetlock joint.”
Distal Tarsitis: Inflammation associated with the lower joints of the horse’s tarsus (or hock).
Dorsal: Toward the front of the limbs (below the levels of the carpus and tarsus) and toward the upper aspect of the head, neck, back, and pelvis. “The horse’s withers are dorsal to the ribs.”
Dorsal Plane: Passes through the head, body, or limb parallel to its dorsal surfaces.
Dorsal Subluxation: Abnormal repositioning or dislocation of a limb structure in a forward direction or a body structure in an ascending direction.
Dorsiflexion: Bending of the spine in a way that moves either end away from the ground surface.
Dorsolateral: Toward the front and outside of the lower limb (below the levels of the carpus and tarsus). “The outside toe quarter is dorsolateral to the center of the navicular bone.”
Dorsomedial: Toward the front and inside of the limb (below the levels of the carpus and tarsus). “The inside toe quarter is dorsomedial to the center of the navicular bone.”
Drifting: Orientation of the horse’s spine in a way that is not consistent with its trajectory (directional path of movement).
E
Eccentric Muscle Action: Relaxation or lengthening of muscle fibers.
Etiology: Cause or origin.
Excursion: Excessive up-and-down movement of one or more of the horse’s body parts.
Extrinsic: Originating from outside of the horse’s body or respective body part.
F
Fascia: A thin sheath of fibrous tissue encasing muscle or other organ.
Fibrocartilagenous Joint: Formed via the presence of an intervertebral disc.
Fibro-Osseous Junction: The site at which a ligament or tendon attaches to bone.
Fibrotic Myopathy: Pathologic condition characterized by the presence of scar (or fibrotic) tissue within one or more muscle bellies. Scar tissue can deleteriously affect the pliability of the muscle(s) within which it develops, thereby having the potential to precipitate biomechanical lameness.
Fibrotic Tissue/Fibrosis: Scarring that typically forms pursuant to an injury and local tissue damage.
Flexor Tendonitis: Inflammation of the superficial and/or deep digital flexor tendons.
Flexural Deformity: Excessive bending of one or more joints in response to disproportionate tension of the flexor apparatus.
Flight Path: The track of a limb or foot as it advances through the air during the non weight-bearing phase of the stride.
Flight Phase of Stride: The phase of a horse’s stride during which the respective limb is airborne (not in contact with the ground surface).
Forging: Striking of a forelimb with the ipsilateral hind limb (on the same side of the horse). Usually occurs as the toe of the hind foot strikes the heel of the ipsilateral forefoot at the trot. Also known as overreaching.
Fracture: A break or fragmentation. “Blunt trauma resulted in fracture of the underlying bone.”
Fusion: The coalescence of two or more structures to form a single entity.
G
Gateado: A smooth and supple quality possessed by superior-moving Peruvian Paso horses.
Greater Trochanteric Bursitis: Inflammation of the greater trochanteric bursa, which is a synovial sac that lubricates the middle gluteal muscle tendon as it courses over the greater trochanter of the femur just outside of the hip joint. This condition is often referred to as whorlbone in horses.
Ground Reaction Force (GRF): The force exerted by the ground surface on a horse’s limb that is in contact with it. Vertical (up-and-down), transverse (side-to-side), and sagittal (front-to-back) ground reaction forces are experienced by each limb during the latter’s respective stance phase of the stride.
H
Hyperflexion: Flexion of a joint beyond normal or expected limits.
Hypermetric: Movement (such as flexion of the limbs) beyond normal limits.
Hypoflexion: Flexion of a joint short of normal or expected limits.
Hypometric: Movement (such as flexion of the limbs) shy of normal limits.
I
Innervation: Nerve supply.
Interference: A lateral gait deficit in which one foot contacts the inside of the opposing limb during flight. This is most commonly observed in horses that wing-in or plait, due to the close proximity of contralateral limbs during this activity. Also known as brushing.
Inter-: Between.
Intermittency: Alternately appearing