Page 111 - Adams and Stashak's Lameness in Horses, 7th Edition

Examination for Lameness 77

the back length and that the hip should be at least two‐ The loin is located along the lumbar vertebrae from
thirds the length of the back (Figure 2.9). the last thoracic vertebrae to the lumbosacral junction
VetBooks.ir formed by the seven cervical vertebrae. The neck should tively short. Horses termed “long‐backed” often have an
The shape of the neck is determined by the “S” shape
(Figure 2.9). The loin should be well muscled and rela­
acceptable back length but a long, weak loin. A horse
have a graceful shape that rises up out of the withers, not
dipping ventral (downward) in front of the withers. The with a weak and/or long loin and loose coupling (flanks)
thickest point in the neck should be at the ventral limits. tends to have a hollow back. (The coupling is the area
Ewe‐necked horses often have a long, ventral curve to behind the ribs and in front of a vertical line dropped
the neck that appears to attach low on the chest. The from the point of the hip). A horse that has a chronic
attachment of the neck muscles to the shoulders should hollow back may be predisposed to focal lumbar pain,
be smooth. The dorsal (upper) neck length (poll to with­ pinched nerves, or vertebral damage. In addition, kin­
36
ers) should be twice the ventral (lower) neck length ematic studies have documented that even subtle
(throat latch to chest). This is dictated to a large degree hindlimb lameness can alter movement of the thora­
by the slope of the shoulder. A horse with a steep shoul­ columbar region, potentially contributing to secondary
der has an undesirable ratio (approaching 1:1) between musculoskeletal pain in the region. 19
the dorsal and ventral neck lengths. 36 The loin and coupling transfer the motion of the
The withers should blend gradually into the back, hindquarters up through the back and forward to the
ending ideally at about the midpoint of the back. In one forehand; therefore, they should be strong and well con­
study all circumference measurements and the majority nected. A short, heavily muscled loin may have great
of the length measurements in a group of National Hunt strength, power, and durability but may lack the flexibil­
racehorses were significantly correlated with the height ity of a more moderately muscled loin. A lumpy appear­
of the horse at the withers. The back behind the withers ance in the loin may indicate abnormal alignment
40
should resemble a natural place for a saddle, beginning (subluxations) of the vertebrae or damage to the supras­
with prominent withers located above or behind the pinous ligament. 36
heart girth. The neck and forearm muscles and the liga­ The croup is measured from the lumbosacral junction
mentum nuchae should attach at the highest point of the to the tail head. The croup should be fairly long, because
withers. There should not be a prominent dip in the mus­ this is associated with a good length to the hip and a
cles in front of or behind the withers (Figure 2.10). Low desirable forward placement of the lumbosacral articu­
(mutton) withers limit a horse’s ability to raise its back as lation. The top line (the back) should be short in relation
it lowers and extends its neck. A horse with a well‐sloped to the underline. Such a combination indicates strength
shoulder usually has correctly placed withers. plus desirable length of stride.
The longissimus muscles that run along the spine
should be flat and appear strong rather than sloped and
weak. The back muscles aid to counteract the gravita­ Substance
tional pull from the weight of the horse’s internal organs Thickness, depth, and breadth of bone, muscle, and
and to support the rider’s weight. other tissues are described as “substance.” Muscle

Figure 2.10. Marked ventral curvature or lordosis of the back is considered to be undesirable because it may predispose to back problems.