984 DISEASES OF THE HOCK. 



horses, when rising or lying down, are better able to protect the injured 

 limb, and may be left free in a box, though even then a dressing 

 is useful, if the animal does not attempt to displace it by violently 

 flexing the limb. In cows, Detroye applies a gutter-shaped splint to 

 the back of the hock-joint, and fastens it by straps to the tibia and 

 metatarsus ; others employ two lateral splints of wood, shaped 

 to the leg and secured by straps and adhesives. 



Wounds of the flexor tendons heal with still greater difficulty 

 unless rendered aseptic, but that asepsis is quite possible is shown 

 by Martens' and Griiner's cases. Particular precautions are necessary 

 in injuries about the tuberosity of the os calcis. 



D. DISEASES OF THE HOCK. 

 I. FRACTURE OF THE BONES OF THE HOCK. 



(a) Fracture of the os calcis. Fractures of the bones of the hock 

 are, on the whole, rare, though cases have been seen, especially of 

 the calcis and astragalus bones. Apart from those described above 

 in which the Achilles tendon is torn away from the tuberosity of the 

 calcis, fractures of this bone are produced by external violence, by 

 kicks, or sometimes by blows with the farrier's hammer. Detroye 

 saw three cases — one in a horse, one in a steer, and one in a calf. 

 The horse had produced the fracture by slipping when rising in the 

 stable. The bone was broken just above its articulation with the 

 astragalus. In the steer, fracture was caused by mounting a cow, 

 and in the calf, by falling into a ditch. The same causes which 

 produce rupture of the Achilles tendon may of course lead to fracture 

 of the os calcis. 



The symptoms and course closely resemble those of rupture of the 

 Achilles tendon, which in this fracture also loses its lower point of 

 insertion, though fracture of the calcis is generally more painful than 

 rupture of the tendon. The broken fragment is drawn upwards 

 by the tendon, and the animal is totally unable to stand on the limb, 

 which collapses. All the joints are excessively flexed, particularly 

 the tarsus. In moving, the limb is lifted and the metatarsus and 

 phalanges dragged, the tendo Achillis and perforatus appearing 

 relaxed. Crepitation is sometimes heard, whilst in compound fractures 

 splinters of bone may possibly be detected in the wound. 



In horses and oxen treatment is rarely successful, but in small 

 animals, which offer some chance of recovery, it may be attempted. 

 Union is rendered difficult by the displacement of the fractured parts 

 consequent on the pull of the Achilles tendon, by their defective 



