Swayback, also known clinically as lordosis, [1] refers to abnormally bent postures in the backs of humans and of quadrupeds, especially horses. Extreme lordosis can cause physical damage to the spinal cord and associated ligaments and tendons [1] which can lead to severe pain. In horses, moderate lordosis does not generally impact an animal's usefulness and does not necessarily cause lameness. [1]
Swayback posture in humans is characterised by the posterior displacement of the rib cage in comparison to the pelvis. It looks like the person has a hyperextension of the lower back, however this is not necessarily the case. Most sway-back exhibits a posteriorly tilted pelvis; the lumbar region is usually flat (too flexed) and not hyperlordotic (too extended). [2] [3]
Usually called "swayback", soft back, or low back, an excessive downward bend in the back is an undesirable conformation trait. Swayback is caused in part from a loss of muscle tone in both the back and abdominal muscles, plus a weakening and stretching of the ligaments. As in humans, it may be influenced by bearing young; it is sometimes seen in a broodmare that has had multiple foals. However, it is also common in older horses whose age leads to loss of muscle tone and stretched ligaments. It also occurs due to overuse or injury to the muscles and ligaments from excess work or loads, or from premature work placed upon an immature animal. Equines with too long a back are more prone to the condition than those with a short back, but as a longer back is also linked to smoother gaits, the trait is sometimes encouraged by selective breeding. It has been found to have a hereditary basis in the American Saddlebred breed, transmitted via a recessive gene. [1] Research into the genetics underlying the condition has several values beyond just the Saddlebred breed as it may "serve as a model for investigating congenital skeletal deformities in horses and other species." [4]
The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.
An intervertebral disc lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint, to allow slight movement of the vertebrae, to act as a ligament to hold the vertebrae together, and to function as a shock absorber for the spine.
Kyphosis is an abnormally excessive convex curvature of the spine as it occurs in the thoracic and sacral regions. Abnormal inward concave lordotic curving of the cervical and lumbar regions of the spine is called lordosis. It can result from degenerative disc disease; developmental abnormalities, most commonly Scheuermann's disease; Copenhagen disease, osteoporosis with compression fractures of the vertebra; multiple myeloma; or trauma. A normal thoracic spine extends from the 1st thoracic to the 12th thoracic vertebra and should have a slight kyphotic angle, ranging from 20° to 45°. When the "roundness" of the upper spine increases past 45° it is called kyphosis or "hyperkyphosis". Scheuermann's kyphosis is the most classic form of hyperkyphosis and is the result of wedged vertebrae that develop during adolescence. The cause is not currently known and the condition appears to be multifactorial and is seen more frequently in males than females.
The American Saddlebred is a horse breed from the United States. This breed is referred to as the "Horse America Made". Descended from riding-type horses bred at the time of the American Revolution, the American Saddlebred includes the Narragansett Pacer, Canadian Pacer, Morgan and Thoroughbred among its ancestors. Developed into its modern type in Kentucky, it was once known as the "Kentucky Saddler" and used extensively as an officer's mount in the American Civil War. In 1891, a breed registry was formed in the United States. Throughout the 20th century, the breed's popularity continued to grow in the United States, and exports began to South Africa and Great Britain. Since the formation of the US registry, almost 250,000 American Saddlebreds have been registered and can now be found around the world, with separate breed registries established in Great Britain, Australia, continental Europe, and southern Africa.
Lordosis is historically defined as an abnormal inward curvature of the lumbar spine. However, the terms lordosis and lordotic are also used to refer to the normal inward curvature of the lumbar and cervical regions of the human spine. Similarly, kyphosis historically refers to abnormal convex curvature of the spine. The normal outward (convex) curvature in the thoracic and sacral regions is also termed kyphosis or kyphotic. The term comes from the Greek lordōsis, from lordos.
Lordosis behavior, also known as mammalian lordosis or presenting, is the naturally occurring body posture for sexual receptivity to copulation present in females of most mammals including rodents, elephants, and cats. The primary characteristics of the behavior are a lowering of the forelimbs but with the rear limbs extended and hips raised, ventral arching of the spine and a raising, or sideward displacement, of the tail. During lordosis, the spine curves dorsoventrally so that its apex points towards the abdomen.
Equine conformation evaluates a horse's bone structure, musculature, and its body proportions in relation to each other. Undesirable conformation can limit the ability to perform a specific task. Although there are several faults with universal disadvantages, a horse's conformation is usually judged by what its intended use may be. Thus "form to function" is one of the first set of traits considered in judging conformation. A horse with poor form for a Grand Prix show jumper could have excellent conformation for a World Champion cutting horse, or to be a champion draft horse. Every horse has good and bad points of its conformation and many horses excel even with conformation faults.
The psoas minor muscle is a long, slender skeletal muscle. When present, it is located anterior to the psoas major muscle.
The abdomen is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. The area occupied by the abdomen is called the abdominal cavity. In arthropods, it is the posterior tagma of the body; it follows the thorax or cephalothorax.
The femoral nerve is a nerve in the thigh that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee. It is the largest branch of the lumbar plexus.
Saddle seat is a style of horse riding within the category of English riding that is designed to show off the high action of certain horse breeds. The style developed into its modern form in the United States, and is also seen in Canada and South Africa. To a much lesser extent, it is ridden with American horse breeds in Europe and Australia.
The nuchal ligament is a ligament at the back of the neck that is continuous with the supraspinous ligament.
Active sitting is the practice of enabling or encouraging individuals to engage in physical activity while seated. It is also commonly known as dynamic sitting. The underlying notion highlights the advantages of incorporating flexibility and movement while sitting, as it can positively impact the human body and allow the completion of certain tasks that require sitting. "Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated." One of the earliest forms of active sitting is the common rocking chair which allows forward and backward swaying motion.
The back describes the area of horse anatomy where the saddle goes, and in popular usage extends to include the loin or lumbar region behind the thoracic vertebrae that also is crucial to a horse's weight-carrying ability. These two sections of the vertebral column beginning at the withers, the start of the thoracic vertebrae, and extend to the last lumbar vertebra. Because horses are ridden by humans, the strength and structure of the horse's back is critical to the animal's usefulness.
Lameness is an abnormal gait or stance of an animal that is the result of dysfunction of the locomotor system. In the horse, it is most commonly caused by pain, but can be due to neurologic or mechanical dysfunction. Lameness is a common veterinary problem in racehorses, sport horses, and pleasure horses. It is one of the most costly health problems for the equine industry, both monetarily for the cost of diagnosis and treatment, and for the cost of time off resulting in loss-of-use.
The tail of the horse and other equines consists of two parts, the dock and the skirt. The dock consists of the muscles and skin covering the coccygeal vertebrae. The term "skirt" refers to the long hairs that fall below the dock. On a horse, long, thick tail hairs begin to grow at the base of the tail, and grow along the top and sides of the dock. In donkeys and other members of Equus asinus, as well as some mules, the zebra and the wild Przewalski's horse, the dock has short hair at the top of the dock, with longer, coarser skirt hairs beginning to grow only toward the bottom of the dock. Hair does not grow at all on the underside of the dock.
The pelvis is the lower part of the trunk, between the abdomen and the thighs, together with its embedded skeleton.
The vertebral column, also known as the backbone or spine, is the core part of the axial skeleton in vertebrate animals. The vertebral column is the defining characteristic of vertebrate endoskeleton in which the notochord found in all chordates has been replaced by a segmented series of mineralized irregular bones called vertebrae, separated by fibrocartilaginous intervertebral discs. The dorsal portion of the vertebral column houses the spinal canal, a cavity formed by alignment of the neural arches that encloses and protects the spinal cord.
Williams flexion exercises (WFE) – also called Williams lumbar flexion exercises – are a set of related physical exercises intended to enhance lumbar flexion, avoid lumbar extension, and strengthen the abdominal and gluteal musculature in an effort to manage low back pain non-surgically. The system was first devised in 1937 by Dallas orthopedic surgeon Dr. Paul C. Williams.
Spinal posture is the position of the spine in the human body. It is debated what the optimal spinal posture is, and whether poor spinal posture causes lower back pain. Good spinal posture may help develop balance, strength and flexibility.