Horse anatomy: The back

The strength and structure of the back of a horse are critical for the usefulness of the animal. Since a horse is used for a variety of activities, it therefore is necessary for the user of the animal to understand the strengths and weaknesses that can occur with a particular horse. The back is a complex design of bone, muscle, tendons and ligaments that all work together to allow a horse to support the weight of a rider.

The shape of a horse’s back can vary from horse to horse, and it can change on an individual horse over the years, as the horse ages. The topline’ of the back is the upper curvature of the withers through the back and to the loin area, whereas the underline’ is the length of belly from the elbow to the flank. Both lines work together, to enable the horse to move flexibly. The abdominal muscles where the underline is, can provide tremendous support to the back when well conditioned. A long underline’ in relation to a shorter topline’ is ideal for riding activities.

The average horse can carry up to approximately 25% of its own body weight. This also depends on body structure or the conformation and the physical condition of the horse. In other words, a horse with well-developed abdominal and back muscles, will be able to carry more weight for a longer time, than one that is not in good shape.

A roach’ back and a sway’ back are two primary flaws in back conformation. A roach’ back or a straight back on a horse is when there is insufficient curvature of the spine and is not as common as a sway’ back or a normal back. The sway back is when there is too much curvature. Either conformation can be distressful to a horse, but can also be, if not overcome completely, than aided with proper attention.

The ideal length of a horse’s back is one third of the entire length of the body. A long backed horse is when the length from the peak of the withers to the point of the hip exceeds a third of the overall body length or from the point of the shoulder to the point of the buttock, excluding the head and neck. Whereas, a short back is less that one third of the body length.

An example of a long backed horse might be that of a gaited’ horse, such as an American Saddlebred or a Tennessee Walking Horse, though not all long backs are gaited’. The advantage of riding these types of horses is that the back is flexible, making the back flatter, quieter and an overall smoother ride. The disadvantage is that it is difficult for the horse to round his back up for tight, quick maneuvers. An example of a short back could be but not necessarily is Arabians, Morgans or the American Quarter Horse. The advantage to a short back is that the horse is quick, agile and strong, able to change direction with ease. However, a short back is usually less flexible and could lead to spinal arthritis.

In determining the conformation of the back of a horse, a rider can decide if a particular horse will be a suitable mount. It will tell the rider whether or not the horse in question will suffer from exposure to the work determined by that rider. If an animal is showing signs of back pain, a veterinarian experienced in large animal care or an experienced horse owner can palpate the back of a horse to pinpoint sources of pain and from there and assess the most likely cause of the pain, thereby following the proper course of treatment.

When studying the anatomy of a cat, it’s hard to not be impressed. It seems as though everything about those felines’ bodies, from their ears to their toes, are designed to hunt and survive. A cat’s legs, in particular, are very important, as without them the cat would have great difficulty moving. As is the case with every part of the cat’s body, these seem to have been carefully designed in order to attain maximum speed, power and efficiency.

A cat’s back legs are incredibly strong, with firm muscles that allow the cat to jump on its prey or propel itself forward with a great burst of speed. When you see your cat suddenly sprinting through the house or jumping up onto a seemingly unreachable countertop, it’s using the sharp angle of its knees and the “heels” of its hind legs, which is the section where the leg bends. When you consider the angle at which this knee is placed, and imagine the cat pushing off from the ground using this knee, it’s no wonder it can rip across the floor at such ridiculous speeds.

A cat’s front legs, mainly used for catching prey or defending itself, are also composed of powerful muscles. Not only can the forelegs be tucked comfortably under the cat’s body in order for it to rest or crouch down, but they can be spread wide apart to “hug” an opponent and stay close to their body. Cats also have very refined wrist muscles, which allow it to more effectively catch and hold onto its prey.

Your cat has claws on each paw, which pair up with their teeth in order to kill their prey and weaken their foes. Each of a cat’s toes comes equipped with a single claw, and these can be retracted to avoid injury and keep them from becoming blunt. A cat will sharpen its claws by chewing at the tips and scratching on rough surfaces. As soon as a cat strikes with its paw, a muscle in its leg will pull on a tendon, which pulls on the muscle to which the claw is attached, and allows each of the claws to come out. If you’ve ever been scratched by a cat, not only are you probably aware of how quickly they can pull out their sharp claws, but of how much pain they can cause.

Of course, a domestic housecat will most likely be using its paws for cleaning itself, not hunting mice, and nature has taken care of this function as well: not only can a cat’s front paws easily curve around its head when scrubbing behind the ears, but the cat can also turn its palms upwards in order to wash its toes, or apply saliva to the paw and then run it across various sections of fur. If you observe your cat, you’ll notice that it can stick its legs up straight in the air in order to clean those hard-to-reach places, and that it can easily spread apart its toes in case dirt is caught in-between.

From cleaning to hunting, you’ve probably noticed that your cat’s legs seem more than capable of doing it all. Just another one of the many wonders of these fascinating animals.

Our cats’ eyes fascinate us, especially the vertical slit of their pupils and that glow in the dark feature! Those two aspects of their eyes most attract our attention because they differ so obviously from our own. We look down at our cats and wonder how different the world they see is to the one we perceive, recognizing it’s not just about our different heights above the ground.

Some anatomical articles about eyes these days, although possibly only www.peteducation.com’s article on the anatomy of cat’s eyes, like to compare them to onions, with distinctive layers. These layers being called the outer fibrous tunic, middle vascular tunic, and inner nervous tunic. It is my opinion that using these terms provides at best an over-simplified understanding of the structure of the eye, and at worst is misleading, providing an inaccurate perception of the actual anatomy of a cat’s eye. These terms are not used in this article, instead the description of the anatomy of the cat’s eye begins with its surrounds and continues into the depths of this fascinating orb.

Cat’s eyes, like our own and those of all predatory animals, are located at the front of the head. This facilitates focusing on prey, providing depth perception through observing the target from both eyes at once. Depth perception enables the judgment of distances, vital for a cat to determine when to attack and how far to pounce.

Beside the standard two eyelids, cats have a third nictating membrane, although it is rarely seen. This third eyelid is semi-transparent and can therefore be used to protect the eyeball while still allowing some vision. It is generally used when the cat is fighting, usually another cat or perhaps reluctant prey, or when traversing thick, tangled underbrush. It is located at the bottom of the eye and may show when our cats are ill; it often shows when cats are anesthetized.

The eyeball is roughly spherical in shape and held within the orbit (eye socket) by three pairs of muscles, that also control its movement, ligaments and the extrusions of the orbit, the way the bone of the skull is shaped around the hole. Although the muscles of both eyes are independent of each other, their actions are co-ordinated by nerve signals from the cat’s brain so that both eyes are aimed at the same object. Cats could probably move their eyes independently, as we can if we concentrate on doing so, but this is not a play activity they are noted for. Uncoordinated

Those who enjoy horseback riding and know a lot about the techniques also know that knowing your horse’s anatomy is just as important as nailing those jumps and properly grooming and tacking the horse.

The gaskin is the part of the hind leg that is between the hock and the stifle. In other words, it is the upper part of the hind leg, above the knee, and closer to the animal’s torso. The gaskin is usually wide in most breeds of horses and shows related thickness both inside and outside when the animal is viewed from the rear. The gaskin is a heavily muscled area and can contribute greatly to a horse’s speed, agility, and stamina. It allows the hind leg to reach well under the horse without placing undue stress or strain on the fetlock joint. The angulation and size of the gaskins, as well as muscle density varies among different species of horses for examples, the gaskins of Arabian horses are generally more muscled and located near a well-rounded hip, while the gaskins of Spanish horses are slightly thinner.

There is more to the shoulder than meets the eye. Firstly, it is important to realize that the horse’s shoulder is not actually attached to the spine by a collar bone as it does in humans. Instead, the shoulder is attached to and supports the weight of the front end by sheets of muscle. These sheets of muscle attach the shoulder blade from various points along the cervical vertebrae (bones of the neck), the thoracic spine, and to the ribs. Because of this, the shoulder is designed to be a shock-absorber. It is this design that allows the horse to travel at speed without excessive jarring on the skeletal system, and in turn, the rider.

Conformation

The angle of the shoulder blade also largely influences the absorption of concussion. Ideally, the shoulder should be long from the point of the shoulder towards the withers. It can be identified as the flat bone structure that suspends anywhere from 2 to 6 inches below the withers and slopes forward gradually developing more muscle coverage. As opposed to a shorter, more upright shoulder, a long sloping one allows a greater stride length as well as more opportunity for muscle to attach the scapula to the skeleton of the horse. With more room for muscle, there is a greater potential for stronger movement, better carriage and increased athletic ability. A shorter, upright scapula is not designed as efficiently to absorb the concussion of the front legs when the horse is traveling, has less space for muscle attachment, and a more limited range of motion.

The shoulder depth is measured from the chest, where the base of the neck attaches, to a line drawn down from the withers, and from the withers to the base of the thoracic cavity (the bottom of the ribs), much like a misshapen box. More space in this area also means more space for the scapula to move without limits set by other bony anatomy. If there is a greater depth in this area, there is more freedom of movement contributing to greater expression and a longer stride.

In most horses, the angle of the scapula is an angle parallel to the pastern of the forelimb. Ideally, this angle is 45 degrees, allowing for optimum shock absorption without being in lack of support or lack of flexibility.

Function in Movement

As mentioned, the muscles attaching the shoulder are responsible for absorbing the concussion of the horse as it travels. When the foreleg is in standing position, this is, generally, the halfway point in mobility. As the horse travels forward,