Constant monitoring and early intervention are keys to successful treatmentAs horses move, there is a tremendous concussive force exerted upon their feet, limbs, bones, joints, ligaments, muscles, and tendons. Several factors that work together may cause any one of or a combination of these structures to become sore or injured. As a result of an injury or soreness, a horse's way of going, as well as its willingness and/or ability to work, go to the paddock, load in the gate, and race, may be adversely affected.
There are many factors that may affect a horse's physical soundness. They include: the horse's age, conformation, shoeing, conditioning, gait, speed, stride length, appropriate tack and its fit, handling, footing, and the actions of the people on and around the horse. Any one of or a combination of these factors may cause a horse to become sore or injured.
Recognition and identification of musculoskeletal problem areas of a horse may be done by a variety of examination methods and techniques. In some instances, a horse's way of going is all that is needed to localize the sore area. The other extreme that may be encountered is the need for an in-depth, time consuming lameness exam with auxiliary tests and diagnostic equipment. The end result of any type of lameness exam, however, is the same: the identification of injured or significant sore areas. Once an area is localized, steps are taken to determine the extent and severity of the injury so a prognosis can be made and appropriate treatment started.

No foot-problem horse
The hoof can be involved in a number of abnormal conditions. The more common abnormal conditions include: sole bruising; subsolar abscess; thrush; hoof wall cracks at the toe, quarter, or heel; long toe and underrun heels; seedy toe; contracted heels; corn; navicular syndrome; laminitis (founder); pedal osteitis; and coffin bone fracture. Contracted heels may occur and are often symptomatic of some underlying disease or improper shoeing. These conditions often contribute to or are the underlying cause of serious problems higher in the leg. In Part 1 of this series, the significance of the foot, the hoof-pastern axis, and front end lameness was discussed.
Regardless of the slope of a horse's shoulder and its front-end conformation, an unbroken hoof-pastern axis is important for a horse to achieve and benefit from the maximum natural concussion-absorbing function of its legs.
Many people trim and shoe their horses with front feet angles of 45 degrees to 50 degrees. This frequently results in a broken back hoof-pastern axis. A broken back hoof-pastern axis is also seen when the toes are too long or the heels are too short or underrun. This is mistakenly done in an attempt to increase the stride length of a horse. A broken forward hoof-pastern axis is also possible, but much less common. Any abnormal hoof-pastern axis predisposes a horse to additional problems farther up its legs.
If broken back, a straight hoof-pastern axis may be achieved by trimming of the toe and/or wedging of the heels. Although the pastern flattens out with an elevation of the heel, Dr. Lochner demonstrated a lessening of the strain on the flexors and the suspensory ligament. He also found a majority of horses today have shoulder angles between 55 degrees and 64 degrees, and when they have a straight hoof-pastern axis their hoof angles measure within a few degrees of their measured shoulder angles. When horses are shod with an unbroken hoof-pastern axis, the incidence of the following problems are decreased.

Overview of the front leg
Injury, soreness, and lameness may be associated with any of the bony or soft-tissue structures of the front legs. Often times more than one joint, structure, or limb will be involved. This necessitates constant monitoring in order to detect and treat the problems early. The following conditions are a cursory look at some of the more frequently encountered problems above the feet in the front legs.
Ringbone may involve the bones and joints of the lower leg. These include the coffin bone, short pastern bone, long pastern bone, coffin joint, pastern joint, and fetlock. It is an inflammation, new bone growth, and calcium deposition associated with the bone covering (periosteum = periostitis) and bones (= osteitis), or bone spur formation (= exostosis) of the joints. High ringbone occurs in the region of the pastern, and low ringbone occurs in the region of the coffin joint.
Formation of osselets is a condition of traumatic arthritis of the fetlock joints. As a result of trauma, there is thickening of the fetlock joint's synovial lining and fibrous joint capsule. This is first seen at the front of the fetlock and may progress to the point where calcification of the tissues occurs.
Rundowns are injuries to the back and sides of the fetlocks from abrasion of the track during races.
Fetlock arthritis occurs as a variety of responses to trauma of the fetlock. This traumatic arthritis may involve the fetlock joint capsule and synovial lining with or without production of excess joint fluid and no destruction of supporting ligaments and joint cartilage. In more severe or repeated cases, damage of the joint cartilage and supporting ligaments and possible fracture may occur. Degenerative joint disease, chronic arthritis, bony changes, and loss of range of motion can be the end result.
Sesamoids are the two bones behind the fetlock joint. The suspensory ligament branches attach to the upper one-third of the sesamoid bones as the branches wrap around the fetlock and join the extensor tendon below the front of the fetlock, thus forming a basket that supports the fetlock. The sesamoid bones may be fractured in a variety of ways with or without concurrent damage to the suspensory ligament branches. In addition, sesamoiditis occurs with inflammation of these bones.
Bucked (sore) shins vary from an inflammation of the cannon bone covering (= periostitis) to microfractures of the front of the cannon bone. Other fracture types may also involve the cannon bone.
Splint bones are the two small bones on either side of the cannon bone. When they become enlarged or the tissue between them and the cannon bone becomes enlarged, a splint has developed. The splint bones may also be fractured. They heal slowly.
Carpitis is an acute or chronic inflammation of the knee. It usually is associated with injury and inflammation of the synovial joint lining and the fibrous joint capsule of the knee.
Carpal (knee) arthritis occurs as a variety of responses to trauma of the knee. This traumatic arthritis involves the joint capsule and synovial lining with production of extra joint fluid and some damage to the supporting ligaments, joint cartilage, and/or bones of the knee. In more severe or repeated cases, destruction of the joint cartilage, supporting ligaments, and bone occurs. Various fractures of the bones in the knee occur in association with the development of bone spurs, degenerative joint disease, chronic with degenerative arthritis, bone spur formation, and bony changes which result in a decrease of range of motion and pain.
Suspensory ligament desmitis is the injury and inflammation of the suspensory ligament and/or its branches due to stress. The damage may range from mild inflammation to the point of rupture.
Bowed tendons are the result of strain to the flexor tendons and their tendon sheaths. The superficial flexor tendon is the most common tendon involved. Damage may range from mild inflammation to the point of fiber rupture. As a result of the strain, there is a thickened, bowed appearance to the back of the superficial flexor tendon.
Check ligaments attach to each of the flexor tendons. The superior or upper check ligament attaches to the muscle of the superficial flexor tendon above the knee. The inferior or lower check ligament attaches to the deep flexor tendon below the knee. The inferior check ligament is strained more often then the upper check ligament.
Inflammation of the bursas of the elbow (olecranon bursa) and the shoulder (bicipital bursa) occasionally occur. The various types of arthritis, bone trauma, fractures, and bony changes also occasionally involve the forearm (= radius), the arm
(= humerus), the shoulder (= scapula), and their joints.

Proper balance
As a horse moves, the tremendous concussive force exerted upon its legs is distributed and dissipated by its musculoskeletal system. Several factors that work together may cause any one of or a combination of these structures to become sore or injured. Careful and constant observation will permit early detection and treatment of the myriad problems that befall horses in training. The importance of a solid and balanced foot with a proper hoof-pastern axis as the foundation of a horse and its athletic career cannot be overemphasized. The achievement of an appropriate foot balance and straight hoof-pastern axis is dependent upon the evaluation and subsequent trimming of each individual horse. There is not one set preconceived angle that every horse should mimic. The hoof-pastern axis will be straight when a horse is appropriately shod. The concurrent hoof angles will provide the straight hoof-pastern axis and they will vary with each horse. Such a solid foundation decreases limb trauma and the degree of soreness that develops from the repetitive stresses of athletic performances.