Navicular in horses: tell-tale symptoms to look out for
Lameness is one of the main symptoms of navicular in horses and it is most commonly seen in the front feet. Usually both front feet are affected, which can make it difficult for the owner to identify. This is because when both feet are affected equally, there is no obvious nodding of the head when the horse is trotted up in a straight line. Instead, the stride may look short and choppy. It may be easier to identify lameness by lunging the horse on a circle, because the inside leg takes a greater strain and any pain this causes the horse will trigger head nodding.
Navicular syndrome is a debilitating condition responsible for over a third of chronic lameness in horses. Its symptoms can be so discreet that it creeps up on owners unawares. Good regular hoof care is vital for helping to prevent it occurring and managing the condition in horses diagnosed with it. Symptoms of navicular in horses may start as an intermittent low-level lameness that resolves with a couple of days rest. In the early stages, some horses may “warm out” of the lameness, which means they appear to be stiff as they leave the stable and improve with exercise.
Symptoms of navicular in horses
Other noticeable symptoms of navicular in horses that you may see are the horse stumbling frequently and/or pointing one foot at an angle. A keen eye may notice that the horse subtly puts their toe to the ground slightly before the heel lands when walked on a flat surface and viewed from the side. This toe-heel action occurs because horses with navicular syndrome feel pain in their heel region.
Precise diagnosis of navicular is based on the characteristic signs together with a lameness work-up by your vet. Your vet may employ a number of techniques in locating the source of pain, including injecting local anaesthetic around nerves supplying the foot or into joints within the foot. These nerve blocks can narrow down the region the pain is coming from, but they must be interpreted with care as the anaesthetic can diffuse and affect other areas too, not just those areas it was intended for.
If navicular syndrome is suspected, X-rays can be taken of the foot. These focus on two things:
- The shape and balance of the foot, and how the external appearance of the hoof relates to the internal positioning of the bones within the hoof. Here vets look at the angles of various structures in the foot to determine what biomechanical forces are applied to the hoof.
- Appearance of the navicular bone itself is also evaluated. A number of changes seen on the bone, such as new bone formation or loss of bone density, can indicate navicular syndrome. It is worth noting, however, that some horses’ X-rays show changes to their navicular bones and yet have no symptoms or lameness, while others who do have navicular syndrome show no evidence of this on X-ray.
The navicular bone is a small boat-shaped bone, sitting at the back of the hoof and tucked behind the larger pedal bone (sometimes also called the coffin bone). It’s held in place by a number of ligaments.
