Have your horse standing squarely on level ground. Feel for the back edge of the scapula.
Mark the locations for cross-section “A” just behind the scapula. Place another chalk mark across the spine at the lowest part of the spine, just behind the withers. This will be cross section “B”. This position is approximately at the 13th/14th Thoracic vertebrae.
Place the last chalk mark 8″ to the rear of the “B” mark. This is position “C”. Using any of the rock patterns, the 8″ is marked on the cards between B & C.
At position “A” (over withers), use the “A” section cards as shown to find the one which fits the closest. The smallest/narrowest sizes start at S4 and get lager/wider up to S7 and from D4 to D8. This photo shows that for this horse, D4 is too narrow.
This horse measures closet to D5. Double-check by testing with the next size up (wider) and one size down (narrower).
D6 to too wide for this horse. Record the best fitting size on the record sheet. For this horse”: at section “A” (withers) is D5.
Repeat the process at position “B” with the cards labeled “B”. Record the measurement on the record sheet.
And repeat again at “C” position.
The cards have a mark on the profiles to indicate the relative position for the “Rock” patterns.
Transfer this location to the horse using a piece of chalk.
To measure the “Rock”, test with each of the “R” cards to find the one which fits closest. Line up the card parallel to the spine passing through the chalk marks that you just made on the horse.
The “R” cards should be held at right-angles to the horse’s muscles at the “B” position. This means that it will be a little more vertical than right-angles to the shoulder and a “stick out to the side” more than vertical to the loin muscles.
Choose the “R” card size which fits closest. There are 3 sizes: R6, R9 & R12. R6 being the straightest to R12 with the most “Rock”. Record the size on the record sheet.
Record distance between position “B” and position “A”. Using the scale marked on the card at position “A”. The horse in this photo measures 8 1/2″ . While taking the measurement make sure that reference mark “B” on the card lines up with the chalk mark on the horse.
Feel free to call us with any questions: 940-427-3260