The distal limb anatomy horse is the most complex part of the equine hoof and therefore one of the most important in terms of structural integrity, mobility and gaits. There are many things that can go wrong in the equine distal limb which can have a profound impact on the health, performance and life of the animal. This is why it is so important to understand and know the anatomy of this area of the foot. This article will discuss the various structures and their function. It will also cover the tendons and ligaments that are associated with the digits.
The digits of the horse are unique among all animals in that they have four complete digits rather than two as seen in other mammals and primates. This allows for a more versatile and powerful gait that can be utilized by the horse. However, this is not without its disadvantages. The digits are more likely to develop deformities and are more susceptible to stress fractures.
Despite this, the digits have the ability to perform a number of useful movements, including the diagonal limb swing (DILS), which is required for the trot and canter. In order to perform these movements, the digits are supported by the collateral ligaments of the fetlock and pastern. These ligaments are attached to the fetlock and pastern bones respectively and provide medial and lateral support.
These ligaments are essentially thick bands of connective tissue that connect the phalanges together. These ligaments are essential for the stability of the joints and in maintaining limb balance. They are also responsible for allowing movement of the hoof and forelimb within the foot.
There are a number of ligaments that are involved in the articulation of the digits and frog. These include the suspensory ligament, the palmar (intersesamoidean) ligament and the straight and oblique sesamoidean ligaments. Fig 3-24 shows the left forelimb of a horse in palmar view. The superficial and deep digital flexor tendons have been removed to expose the tendons of insertion. This also reveals the navicular bone and the navicular bursa. The navicular bone is a highly stressed structure and may show signs of remodelling on radiographs.
The navicular bone is also a source of pain for horses as it can become lame due to stress. Fortunately, there are a number of ways to treat this issue. One way is to use a navicular bone block. This helps to reduce the pressure on the navicular bone and alleviates the pain. Another way is to apply a topical navicular pad. This can be purchased at most equine stores and is a cost-effective way to help relieve the pain of navicular syndrome in horses. Another option is to have the navicular bones remodelled surgically. This is a more costly option but can be very successful in relieving the pain of navicular syndrome in many horses. This procedure can be performed by a veterinarian.