All About the Neck

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In dressage, we pay a lot of attention to the horse’s neck position. Here’s why the neck is so important.

Reprinted from the October 2017 issue of USDF Connection

By Hilary Clayton, BVMS, PhD, Diplomate ACVSMR, MRCVS

Dressage riders, trainers, and judges devote quite a bit of time to studying and critiquing the position of the horse’s neck. Although this article focuses on the neck in isolation, we must remember that its shape and carriage reflects the way in which the horse uses his entire body.

In this article, I’ll describe the posture of the dressage horse’s neck and, more specifically, how the positioning of the vertebrae affects the shape of the neck.

Anatomy of the Equine Neck

The horse’s neck is broad at the base, where it attaches to the chest, and it tapers toward the poll. Neck conformation of the neck attachment is an indicator of a horse’s suitability for dressage, and it can also be a reflection of the quality of training.

The topline of the neck should curve smoothly upward and outward from the top of the withers, without a dip in front of the withers. The underline of the neck should emerge high from the chest; a neck that emerges too low or too horizontally from the chest makes it difficult for the horse to achieve the correct neck shape and balance for dressage. A well-developed underline and poorly-developed topline are signs of incorrect neck carriage and training.

Figure 1. Relaxed neck position. The vertebrae in the neck are labeled C1 through C7. Note that the vertebral column is on top of the neck at the poll, but passes through the muscles to lie close to the underside at the base of the neck. C1 is above C2, and the vertebrae follow a fairly straight line as they descend in the neck. Courtesy of Dr. Hilary Clayton

The neck has at its core a series of seven cervical vertebrae (named C1 to C7) from the poll to the base of the neck. The vertebrae are joined together by intervertebral discs, ligaments, muscles, and tendons to form a somewhat rigid yet flexible column. The alignment of the vertebrae determines the shape of the neck and the correctness of the neck posture. From the poll, the vertebrae descend through the neck until, at the base, they are close to the underside of the neck as they enter the chest (Figure 1). The vertebrae are in a fairly straight alignment through most of the neck, although there is a downward curve behind the poll and a flattening out at the base of the neck.

The areas where the vertebral column changes direction are the most mobile parts of the neck. Horses prefer to raise, lower, or turn the entire neck from its base rather than moving the joints equally along the length of the neck. One of the consequences of this is the tendency to overbend at the base of the neck and to push out the shoulder while turning. The horse’s ability to move his head independently helps him to stabilize his eyes and the vestibular (balancing) organs in his ears while he is in motion.

The neck contains several large, heavy muscles and accounts for 6 percent of the horse’s weight, or about 75 pounds in an average-sized dressage horse. The head and neck are continuously pulled downward by the effect of gravity and are held up by tension in the nuchal ligament and the topline muscles. With correct training, these muscles are strengthened and the neck develops a more convex topline. The fact that the neck must be supported at all times means that an excessively heavy neck is a disadvantage for a dressage horse: He must expend more effort to hold it up and stay balanced without falling on his forehand.

The two large topline muscles— semispinalis and splenius—play a major role in supporting the neck. Although they are similar in position and attachments, they have different functions. Semispinalis is designed for postural support, whereas splenius is designed to produce movement. Therefore, semispinalis supports the neck in opposition to the effects of gravity, while splenius is responsible for actively raising and bending the neck.

The nuchal ligament is also part of the neck’s support system. It consists of strong elastic cords and sheets located along the middle of the neck, between the left and right topline muscles. The main function of the nuchal ligament is to assist in supporting the weight of the neck during locomotion.

The nuchal ligament has two parts, called the funicular (cord-like) and lamellar (sheet-like) parts. The funicular part has two cords (left and right) that run side by side from the top of the withers to the occipital bone at back of the skull. They are stretched when the neck is lowered, rounded, or telescoped out. When the nuchal ligament is stretched, lateral flexion at the poll causes the funicular part to slide sideways over the top of the spine of C2. You can easily see this from the saddle as the entire crest “flips over” to the inside of the bend. You may see two small jerks as the left and right funicular parts of the nuchal ligament roll over the spine of C2, one after the other. With the horse’s topline stretched, you can flip the crest from side to side by changing the lateral flexion at the poll. If a dressage horse is ridden with the correct lateral positioning at the poll, his crest lies to the inside on turns and circles.

The lamellar part of the nuchal ligament consists of left and right sheets (lamellae) of elastic tissue that stretch from the top of the withers to the vertebrae in the neck. The strongest sheets attach to the spine of C2, where they play an important role in supporting the weight of the neck during locomotion. Weaker sheets that attach to C3, C4, and C5 help to prevent the lower neck from hollowing.

The Neck in Motion

When the horse stands in a relaxed position, as shown in Figure 1, there is no tension in the nuchal ligament and the neck is supported primarily by the supraspinatus muscle. During locomotion, neck posture changes and the nuchal ligament becomes part of the support mechanism.

The neck and head nod downward relative to the horse’s trunk twice in each stride in the walk and trot, and once in each stride in the canter. As the neck descends, the nuchal ligament and the topline muscles are stretched; then the ligament recoils and the muscles shorten to raise the neck. So the neck gently and elastically oscillates down and up in rhythm with the stride.

A horse moving at liberty will hold his head and neck lower in the walk than in the faster gaits. His poll will be at the height of the withers in walk, about four inches higher in canter, and another four inches higher in trot. The angle through which the neck oscillates is greater in walk and canter than in trot. The differences in self-selected poll height are thought to optimize the elastic function of the nuchal ligament in accordance with the range of motion in the oscillations and the nodding frequency in each gait.

In the early stages of dressage training, we encourage the young horse to stretch his neck forward. Doing so stretches the nuchal ligament and facilitates its use in supporting the head and neck. As training progresses and the horse develops a level of collection and self-carriage, the posture and carriage of the neck change: The base of the neck and the withers are raised, and the topline of the neck continues to be stretched as the upper part of the neck and the poll are elevated. Neck oscillations during locomotion decrease progressively as the horse becomes more collected and carries his neck with a higher profile.

Figure 2. Correctly raised neck. The vertebrae in the middle of the neck slope upward and forward with a gently curving line that stretches the topline of the neck. C2 is at the same height as C1, and the topline in front of C2 is horizontal. Courtesy of Dr. Hilary Clayton

The thoracic sling muscles raise the chest and the base of the neck. As a result, the withers are lifted between the scapulae, which gives the trunk an “uphill” inclination. When the base of the neck is lifted and rounded in this way, it avoids using a hinge-like motion that would retract the neck as the poll is raised. With the base of the neck and the withers supported and elevated, the upper part of the neck is gradually raised and rounded while maintaining a stretched topline, as shown in Figure 2. Note how the orientation of the cervical vertebrae has changed as compared with Figure 1. This is a key component in raising the neck correctly. In the relaxed neck shape (Figure 1), C2 is clearly lower than C1, whereas in the correctly raised neck the vertebrae rise to C2, then level out from C2 to the poll (Figure 2).

Positioning the Head and Neck

Movement of the two joints immediately behind the poll changes the horse’s head position. The first joint between the skull and C1 (the (atlanto- occipital joint) flexes and extends to change the angle of the front of the face relative to the vertical. Increased flexion brings the horse’s profile closer to the vertical and closes the angle under the throatlatch. Extension moves the nose further ahead of the vertical and opens the angle under the throatlatch. The atlanto-occipital joint also allows the head to turn from side to side, which has the effect of tucking the cheekbone under the salivary gland that lies below the ear to create lateral flexion at the poll. This is the movement that flips the crest sideways.

The second joint, between C1 and C2 (the atlanto-axial joint), swivels the head and tilts the nose from side to side, putting the ears at different heights. Because this joint does not flex and extend, the overlying topline from the poll to C2 cannot be rounded or hollowed. Instead, it forms a flattened area that should have a horizontal or slightly uphill orientation when the horse works with a correct neck shape, as shown in Figure 2.

Figure 3. Overflexed between C2 and C3. This causes the topline in front of C2 to slope downhill so that the poll is lower than C2. The front of the face is likely to be behind the vertical, with the angle at the throatlatch closed, when the neck is this shape. Courtesy of Dr. Hilary Clayton

The joint between C2 and C3 can flex and extend, bend left and right, and twist a little. The correct amount of flexion at this joint allows the crest of C2 to become horizontal as the horse “crests” over the upper neck. A common fault in dressage horses’ neck posture is for this joint to overflex, which causes C2 to rotate downward toward the poll and gives the appearance of the angle of the neck being “broken” behind C2. When this happens, the neck slopes downward from C2 to the poll (Figure 3). This is a common but serious fault and often results from the rider’s relying on the reins to position the horse’s head.

The horse’s head comes behind the vertical if it is pulled there, either by contraction of the muscles under the neck and skull or by too much tension in the reins. Both are incorrect. A posture in which the poll is low and the head is behind the vertical is not natural for the horse. In the interests of functionally-correct training, we must pay close attention both to the angle of the front of the face and to the slope of the neck immediately behind the poll.

Figure 4. Incorrect elevation of the neck from its base. The neck has been elevated and retracted by using the joints as the base of the neck as a hinge. Note the vertical orientation of the vertebrae in the middle part of the neck, the lack of stretching of the topline, and the fact that C2 is lower than C1. The poll is retracted and excessively flexed so that the
angle at the throatlatch is closed. Courtesy of Dr. Hilary Clayton

Incorrect training raises the poll by using the joint at the base of the neck as a hinge about which the neck angles upward and backward. The withers are not raised and may even sink lower between the scapulae. The poll is retracted as it gets higher, and the topline of the neck becomes shorter and flatter rather than maintaining its length and roundness. The horse tends to overflex between the poll and C1, which has the effect of closing the throatlatch (Figure 4).

Laminitis is a serious and potentially devastating disease. If your horse has a large cresty neck, seek professional advice without delay.

Compare the shapes of the necks in Figures 1 through 4, and note how the curvature of the vertebral column differs among neck shapes. Then try to visualize the position of the vertebrae when you watch a horse working.

Cresty Considerations

The horse’s crest is a wad of fat and fibrous tissue attached on top of the nuchal ligament from the base of the neck to C2. It is sometimes called the nuchal fat pad. If you palpate the tissues on top of the neck, muscle feels firm and resilient, whereas the fattiness of the crest feels softer and more doughy. Moderate crest development adds to the rounded appearance of the neck but must be differentiated from the true topline of the neck when assessing a horse’s neck shape.

The development of an overly exaggerated crest is recognized as a problem, particularly in Baroque breeds. An article published earlier this year in the Equine Veterinary Journal described the University of Seville in Spain. The study focused on Pura Raza Española (PRE) horses; an excessively cresty neck disqualifies a stallion from registration in that studbook.

After evaluating 10,929 PRE horses from 24 countries, the researchers reported that 8 percent of horses were penalized in the conformation score because of the size of the crest, and 0.6 percent had such overdeveloped crests that they were disqualified from registration altogether. Crestyneck scores were higher in males than females, in horses older than six compared with horses younger than three, and in gray horses compared with horses of other colors. The cresty-neck score for PRE horses has a moderate heritability, indicating that the trait can be passed on to an affected horse’s offspring. However, the fact that it is heritable also indicates that the prevalence of the defect could be reduced by selective breeding.

CRESTY-NECK SCORING CHART: Illustrations depict neck appearances veterinarians use in determining whether a horse’s neck is overly cresty. An excessively cresty neck may indicate health problems.

A cresty neck is also a feature of obesity in horses and ponies. This is a red flag because it can indicate that the horse is insulin-resistant and at high risk for developing laminitis. The cresty-neck scoring system (see illustration above) predicts a horse’s risk for metabolic disease. Higher scores are associated with an increase in circulating insulin and a decrease in insulin sensitivity (i.e., insulin resistance). If your horse has a large crest, take measures immediately to reduce his risk of laminitis. Steps may include reducing feed intake, changing his diet, and making sure that he is exercised appropriately. Consult with a veterinarian, an equine-nutrition specialist, or both for advice and guidance.

Meet the Expert

Dr. Hilary Clayton is the professor and Mary Anne McPhail Dressage Chair emerita. She was the original holder of the Mary Anne McPhail Dressage Chair in Equine Sports Medicine at Michigan State University’s College of Veterinary Medicine, East Lansing, from 1997 to 2014. At the same time, she was a professor in MSU’s Department of Large Animal Clinical Sciences.

A world-renowned expert on equine biomechanics and conditioning, Dr. Clayton is president of Sport Horse Science, LC, which is dedicated to translating research data into practical advice for riders, trainers, and veterinarians through lectures, articles, and private consultations. A USDF gold, silver, and bronze medalist, she is a longtime USDF Connection contributing editor and a past member of the US Equestrian Federation’s Dressage Committee.

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