IX] 



SURGICAL DISEASES AND CONFORMATION 



109 



projects out, and can be found by running the 

 finger down the splint bone. Enlargement of 

 this head is not uncommon in France, where it 

 is called a jarde. 



429. Bone Spawm.— This is called a jack or 

 spavin. Consists of a bony growth on the lower 

 portion of the inside of the hock. [See P. 95c?, e, 

 /.) It is an inflammation. In the hock there are 

 four joints, the top one, between the tibia and 

 the astragalus, is a pulley joint, and is the true 

 hock joint; the three lower ones allow only a 

 slight movement, which is chiefly a sliding one, 

 when the hock is flexed. The lowest has least, 

 and the highest most, movement. Hence, as in 

 a splint, the higher the spavin the more serious 

 it is. 



Cause. — Concussion, therefore most common 

 in fast draught horses, hunters, the circus horses 

 that perform much on their hindlegs ; less 

 common in racehorses and light-driving horses. 

 Young horses more susceptible. Actual con- 

 cussion, sprain or rupture of the interosseous 

 ligaments which bind the hock bones together 

 is the cause. 



Symptoms. — Horse starts out lame in a hind- 

 leg and drags his toe, especially going downhill. 

 Lameness disappears or decreases as horse 

 warms up. Will be worse after a hard day's 

 work. A spavined horse will usually wear the 

 shoe of the affected leg thin at the toe. The 

 lameness can often be detected by pushing the 

 horse's hindquarters across the stall. Unless the 

 spavin is very slight or is just forming, a lump 

 can be felt and be seen on the inner lower side 

 of the hock joint just above the straight inner 

 border of the cannon bone. There will gener- 

 ally be heat and pain on pressure. It will be 

 noticed that a spavined horse when turned about 

 to either side will bear most weight on the 

 sound leg. 



A good test is to raise the foot of the suspected 

 leg as far as possible, holding the hock well 

 flexed for a minute or two, and upon releasing 

 the leg the lameness will be much increased if 

 there is a spavin. When there are no external 

 symptoms the injury is in between the surfaces 

 of the bones of the hock ; this is known as occult 

 spavin. In bad cases horses often refuse to lie 

 down because of the pain caused when rising. 



430. Treatment. — In young horses spavin 

 lameness can generally be cured easily. A high- 

 heeled shoe is advisable. We cannot cure a spavin, 

 but we can remove a lameness by means of unit- 

 ing the lower joint or joints of the hock, thus pre- 

 venting any movement and, therefore, pain. This 

 union is made by our assisting Nature to throw 

 out a bony growth which unites the bones to- 

 gether. For slow work a horse which has under- 

 gone such treatment is not decreased in value. 

 Severe blistering may have the desired effect ; but 

 deep pin-firing with an electro-thermocautery 

 needle is the surest method, as the heat reaches 



the inside of the enlargement. The true hock 

 joint, the tendons and their sheaths must not in 

 any way be interferred with. Cocaine must be 

 used before firing. Absolute rest is essential 

 while this union is taking place, therefore the 

 horse should be kept in a sling, or the hock put 

 in plaster of paris for from four to six weeks. 

 The horse must be prepared beforehand with 

 purgatives, and given laxative food and diuretics 

 during the treatment. Turn out afterwards to 

 pasture for three months. In young horses, in 

 early stage, cure may be effected before any bony 

 deposit has taken place by rest, massage and 

 pressure bandages, and suitable diet. The seat 

 of spavin is covered by a binding ligament 

 (astragalus metatarsus), and this ligament often 

 becomes seriously inflamed when a spavin is 

 present. A small tendon (cunean), which is an 

 inward branch of the flexor metatarsus tendon, 

 passes over this ligament, and is attached to the 

 small cuneiform bone on the inner border of the 

 lower row of hock bones. This tendon causes 

 pressure on this ligament and therefore much 

 pain. With the use of local anaesthesia this 

 tendon can be cut, and may save much lameness : 

 in some cases it does no good. 



431. Ringbone. — This consists in a bony de- 

 posit on the pastern bones and varies consider- 

 ably in position and size. P. 96c shows a large 

 completely formed ringbone. It is usually on 

 the sides and front, and tends to form a semi- 

 lunar ring. A ringbone on the large pastern 

 generally causes no lameness unless it interferes 

 with the lower end of the suspensory ligament. 

 If it interferes with the joint between the large 

 and small pastern bones, which is the commonest 

 place of occurrence, it will cause much lame- 

 ness. In this case the deposit will be on the 

 lower head of the large pastern bone or upper 

 head of the small one. It may be on the lower 

 head of the small one and interfere with the 

 coffin joint ; this is most serious. 



Cause.— More common in the hindfeet, and is 

 due to severe concussion on the toe, sprains or 

 fractures setting up inflammation ; and some- 

 times to rheumatoid arthritis. Ringbone may 

 be caused by a horse going on his toes owing to 

 lameness. 



Symptoms. — The deposit can be felt just above 

 the coronet, or higher up on the pastern, unless 

 it is not sufficiently formed. The horse will try 

 to avoid bending his pastern joint more than he 

 has to. 



Treatment.— U in the early stage, absorption 

 of the deposit is looked for by giving rest and 

 suitable diet, and by a severe blistering or pin- 

 firing, as in bone spavin. Allowing the deposit 

 to unite the bones, as in the case of spavin, would, 

 of course, greatly decrease the value of the horse ; 

 therefore the horse should be turned out to 

 pasture in a few days after blistering or firing, 

 to prevent the joints becoming stiff. Neurectomy 



