Poll pain can cause performance, behavior, and welfare issues for horses. Here’s how vets diagnose and treat it.
You can likely relate to the misery of working with a headache—that dull, nagging pain that just won’t go away. For horses, it’s probably no more pleasant. They can’t reach up and massage their temples or lie down in a dark, quiet room when the poll area, at the top of the head, hurts. So they toss their head, fight the bit, act head-shy when you approach with the bridle … whatever they can do to get away from that discomfort.
Diagnosing poll pain and determining its cause is no easy task, either. In fact, our sources tell us what looks like poll pain might be a behavioral issue. Or it might be true pain in the poll, but only because the horse is tensing his neck muscles or repositioning his head to compensate for pain somewhere else. In this article we’ll discuss the hows and whys of poll pain—an elusive, but important, issue in horses.
“Poll” is a layman’s term and, unlike most other body parts, it doesn’t really have an equivalent scientific name, says Sue Dyson, MA, VetMB, PhD, DEO, FRCVS, former head of Clinical Orthopaedics at the Animal Health Trust Centre for Equine Studies, in Newmarket, England. Essentially, it’s the region immediately behind the ears encompassing the first two vertebrae, C1 and C2, also known, respectively, as the atlas and the axis, the atlantoaxial joint between them, and the atlanto-occipital joint at the junction of the atlas with the occipital bone, which is the back part of the skull. The poll also includes all the soft tissues in this occipitoatlantoaxial region.
The soft tissues of the poll extend across the top of the head and even down along the sides of the neck some, says Kevin Haussler, DVM, DC, PhD, Dipl. ACVSMR, of the Orthopaedic Research Center faculty at Colorado State University’s College of Veterinary Medicine and Biomedical Sciences, in Fort Collins. “You could argue that the poll region includes the base of the ears and extends ventrally down to include part of the parotid salivary glands at the base of the ears,” he says.
The poll area incorporates several muscle structures and tendons and ligaments, including the big nuchal ligament that runs along the top of the neck. This ligament attaches to the back of the occipital bone and serves “a very important role in the neck support structures,” Dyson says. It’s also the site of major cranial nerves stemming out from the brain, and the spinal cord is housed deep within the vertebrae.
Signs of Pain
Aside from obvious flinching when you touch the poll area, horses can show various signs of possible poll pain, say our sources.
“They might be less compliant with the rider or be less steady in their head carriage, or the rider might notice uneven rein tension,” Dyson says. Riders might even see physical signs from above while in the saddle, such as swelling or asymmetry in the poll area.
Head-tossing under saddle or on the longe is a standard sign, adds Haussler. “It’s like they’re restless and trying to get comfortable,” he says.
When not working, these horses sometimes “stand like a giraffe, as if to say, ‘Don’t touch me there,’ ” says Haussler. But they might also do the opposite, keeping their head low and extended because flexing hurts too much. They could tilt their head slightly, too. “You can also watch how they eat and how they interact with pasturemates to see if they have any unusual posture with their head and neck,” he says.
Is it Really the Poll?
A problem with detecting poll pain is that the issue isn’t necessarily the poll itself and might not even be pain. “Genuine primary poll pain is very unusual,” Dyson says. “A lot of people suspect it’s poll pain because the horse gets head-shy or tilts his head when working, but these problems are often secondary to something else.”
In general, horses often have vague reactions to pain that don’t always help us hone in on the source, she says. Poor performance and training difficulties could arise from pain anywhere in the body. Sometimes the poll is painful, but only because pain somewhere else is causing the horse to adjust the way he moves his head. “Many horses with hind-limb lameness tilt their heads so much they get sore around the poll region,” Dyson explains.
Head sensitivity, tossing, and tilting can also come from dental pain, temporomandibular joint (jaw) issues, a poorly fitting bit or saddle, too much weight in the saddle, or back pain, adds Haussler.
“You also have to consider that it’s strictly behavioral,” he says. “Has the horse been abused? Hit in that area and now has become head-shy? Or maybe he had pain before that’s resolved but has maintained the behavior.”
If the horse does have true poll pain, where does it come from? While primary poll pain is unusual, bursitis is one source. “Inflammation of the fluid-filled sac, called the bursa, in the poll region, means the horse has bursitis,” Dyson says.
The horse develops cranial nuchal bursitis when the nuchal ligament becomes inflamed and/or infected, says José García-López, VMD, Dipl. ACVS, ACVSMR, associate professor of large animal surgery at the University of Pennsylvania School of Veterinary Medicine, New Bolton Center, in Kennett Square. The nuchal ligament has three bursae, two of which are in the poll, and bursitis can develop in either of these, sometimes bacterial in nature and associated with oozing lesions—a condition also known as poll evil.
Veterinarians don’t know what causes cranial nuchal bursitis, but García-López says it could be associated with repetitive-use injuries.
Horses can sustain poll injuries in accidents, such as when they pull back while tied, says Dyson. “If they pull until the halter or rope breaks, this can create a painful injury to that area,” she says.
Any kind of fall onto the neck, such as a rotational fall over a jump, could also induce poll pain, she adds.
But because C1 and C2 are well-protected by surrounding structures, fractures are very rare, says Dyson. “Mostly we’re dealing with soft tissue injuries after poll trauma,” she explains.
Again, poll problems might be caused by repetitive or overuse injuries—from working in certain flexed head and neck postures, for example—though currently no studies have proven it.
“No evidence supports that working horses in a position of low, deep, and round would cause soreness, unless it was prolonged, when inevitably the poll region might become uncomfortable,” Dyson says.
Still, it “makes sense biomechanically,” says Haussler. “It could be like carpal tunnel syndrome. You don’t have to have the wrist cranked down to the limit, but just that repetition of having a horse holding its head and neck in a difficult posture relentlessly, for years on end, might contribute to pain in the poll.”
Halters and bridles pass right over the poll region, exerting pressure. Haussler likes a broad contact that diffuses the forces. “Rope halters have a lot of sharp contact over the poll,” he says. “Sure, they make the horse pay attention, but some people use it as a tool to cut corners around good training, and that can lead to injury.”
Bitless bridles that exert a lever effect over the poll area could potentially cause injury, as well, although research in that area is lacking, says Dyson. “There’s no scientific evidence either way, but watching how some bitless bridles work gives an indication of the potential to cause discomfort.”
A contoured and padded bridle designed to reduce poll pressure showed positive effects in a small initial study, Dyson adds. Regardless of the design, though, a bridle must fit correctly to minimize undue forces on the poll.
Indeed, removing tack pressure can help relieve forces that might lead to poll pain, says Haussler. “If they’re sensitive there, make sure they’re ridden long and low on the reins,” he says. “And if you use draw reins, keep them loose or use elastic. Let their heads move.”
Haussler says veterinarians should focus their clinical exams on finding pain that’s coming from soft tissue, hard tissue, or nerves. To check the soft tissue, have the horse lower his head to knee level. “With the head in a normal elevated position, the poll muscles are hypertonic (tense) because they help control head position,” he explains. “As they lower the head, the nuchal ligament engages, allowing the muscles to relax.”
At knee level, veterinarians can palpate muscles and the nuchal ligament where it inserts into the skull, “like a shoulder massage,” to check for heat, swelling, or fluid accumulation. They should also make sure any firm masses soften. “All those structures should relax,” he says.
Next, they can check hard tissue with the head in the same position, Haussler says. “Feel around the back of the skull for any bony inflammation or proliferations or any bony areas that elicit a pain response.”
For nerve-related issues, examine muscle development, he says. “The first and second cervical spinal nerves (in the upper cervical vertebrae) provide sensory innervation to the skin and muscles (C2 spinal nerve) and motor innervation to the poll and upper cervical muscles (C1 spinal nerve),” he says. “Neurologic disorders of these cervical nerves may be associated with increased skin sensitivity or with asymmetrical muscle development or strength of head movement, so there might be a difference in rein tension.”
Clinicians can also check for symmetrical sensitivity by running a needle or ball point pen cap along each side of the poll and seeing if they get the same reaction on both sides, he adds.
The vertebral joints should have good range of motion, which practitioners can check by placing one hand on the jaw and the other on the poll to see if the horse willingly flexes and extends the head, says Haussler. Owners can perform lateral range of motion tests by holding the halter nosepiece and the poll over the atlas and bringing the horse’s head to the side.
“About 45 degrees is good for lateral bending,” he says. Carrot stretches—using a treat to bring the horse’s nose to his chest and around to each side—can give more insight into a horse’s poll flexibility. Movements should be fluid and coordinated, not jerky or bouncy.
While these tests are all useful, it’s important to remember that some horses act like they have pain when they don’t, or don’t anymore, because they’ve become “sensitized” to feeling pain and learn to anticipate it, says Dyson. “You have to go slowly and carefully, palpating other areas and then the poll region,” she says. “It’s important to not overinterpret your findings because horses can be head-shy for many reasons, including anticipating that something’s going to bother them (even if it might not).”
Radiographs (X rays) can give some insight into poll pain, but our sources agree that findings are rarely conclusive (except in the case of fractures). It’s complicated to get more than a single view—just the side view—because others (from above and below the head) are “difficult to acquire in a standing horse,” says Dyson. Still, the single view can show changes in bone density or bony irregularities.
For Dyson, however, just because X rays show changes doesn’t mean they’re causing pain. “Prepurchase radiographs show quite a few horses with bony changes at that area of insertion of the nuchal ligament, for example, but many of them are completely asymptomatic,” she says.
Ultrasound can complement X rays, says Haussler. In particular, they can together reveal the telltale fluid buildup of bursitis, he says. They can also point to ossified areas within muscles or ligament or tendon insertions—soft tissues that have mineralized into bony formations (usually due to overuse injuries, he adds).
Computerized tomography (CT) and magnetic resonance imaging (MRI) would be “the gold standard” for finding pathological changes in the poll, says Haussler. Most machines can image the head and the entire poll area down to C3. However, CT and MRI are cost-limiting for many owners, and MRI of the poll requires general anesthesia, which isn’t risk-free, he says.
Poll pain treatment depends heavily on the diagnosis, says Haussler. “It could be acute trauma or infection, or you could have a piece of fence post stuck in there, so it all depends on what you find,” he says.
In most cases—foreign body presence excepted—“rest is sufficient,” says Dyson.
Rest and rehabilitation should include “letting the horse be a horse, eating off the ground with their necks extended,” says Haussler. Meanwhile, riders should cross-train so their horses aren’t always keeping the same head and neck position. Pre-work carrot stretches could help, too.
A “trial” of non-steroidal anti-inflammatory drugs (NSAIDs) could help if rest alone doesn’t, especially if the horse has arthritis or bony proliferations that only hurt when he’s asked to assume a flexed head and neck posture, Haussler explains. He also recommends acupuncture by a licensed therapist, as well as massage and laser therapy with a safe laser (that doesn’t burn the skin). Sometimes veterinarians are successful using shock wave therapy to treat pain associated with bony changes, he adds.
Corticosteroids can help with bursitis, says Dyson. However, surgery might be a better alternative if the bursa contains mineralized tissue and its walls have thickened due to inflammation, adds García-López.
If the horse has behavioral issues associated with poll pain or past abuse, address those during treatment, as well. “He might need deconditioning,” says Haussler. “Anticipation adds such challenges.”
The poll isn’t necessarily a fragile area, but our sources agree it’s a site that gets subjected to frequent pressure in riding horses. It also runs the risk of getting sore if the horse uses his head to compensate for pain elsewhere in the body. Depending on results of clinical exams and imaging, rest can often resolve true poll pain. While recognizing and diagnosing poll pain can be a challenge, the most critical part is understanding the primary cause—which could be entirely unrelated to the poll itself—and addressing that issue.