HORSESHOEING. 37 



is borne by the perforans tendon, and a still smaller amount by 

 the perforatus. The coronary joint is supported chiefly by the 

 perforatus, assisted by the perforans. The pedal joint is pressed 

 fonvard and upward by the perforans tendon passing in a curve 

 beneath the navicular bone. Each of these three structures bears 

 its normal proportion of the body-weight Avhen the three pha- 

 langes, as view^ed from the side, form a continuous straight line 

 from the fetlock- joint to the ground. In such a case the obliquity 

 of the long pastern will be the same as that of the toe (see 

 Foot- Axis, p. 70). 



Raising the toe by means of a tip, a full shoe with thinned 

 branches or a toe-calk, or paring away the quarters will tilt the 

 OS pedis backward, break 

 the foot-axis backward in 

 the pedal joint and to a 

 less extent in the coron' 

 ary joint, and increase 

 the tension of the per- 

 forans tendon consider- 

 ably and of the perfo- 

 ratus slightly. These 

 tendons tightening be- 

 hind the fetlock - joint 



force it forward, causing Rig^t forefoot viewed from the external side: A. os 



tVi<^ Inno- T^n<?fA-m fn <4tnnf] coronae; B, os pedis; C. external lateral cartilage; a, 



tne long pastern to Stana ,^^g^^, p^^^, y^^^^^^^. j,, Ugament uniting the lateral 



SteeOer and takinsr some cartilage with the os coronae; c, aponeurosis joining 



J ' ^ lateral cartilage and os pedis. 



strain from the suspen- 

 sory ligament. Hence, the perforans tendon is under greatest 

 tension, and the suspensory ligament under least tension, when 

 the foot-axis is broken strongly backward. 



Shortening the toe, or raising the quarters by heel-calks or 

 thickened branches, will tilt the os pedis forward, break the 

 foot-axis forward in the pedal joint, and wall greatly lessen the 

 tension of the perforans tendon. The aggregate tension of 

 perforans and perforatus tendons being diminished, the fetlock 



