Measuring Your Horse’s Hoof Structure and Growth: Wall Length and Flare
In this graphic, the large gap between the PHP tool and the dorsal wall indicates a large amount of flare (reference A). This hoof wall is naturally flaring out and trying to chip off the excess hoof wall to achieve its natural length. Flare is an indication that a trim is needed. You can view such signs of flare with or with out shoes.

If the angle becomes less steep (reference B) as you continue measuring the full toe length, then separation is present.
Measure ½ inch (1.3 cm) down from the coronet band. This is the angle at which the well-connected hoof wall wants to grow (reference C).

At the solar surface you can easily measure the excess flare and length of the wall with the PHP.
In this graphic, the white line has been compromised. It is evident that a great amount of stress has been put on the lamina that connects the hoof wall to the coffin bone. When the lamina is weakened due to stretching and separation, this can lead to infection. In this case it is evident that black fungus has penetrated the white line. (reference D)

It is painful for the horse to have the overgrown wall tearing away from the coffin bone. For a shod horse, you will need to do such inspections and measuring after the shoes are pulled.
Gauging flare with the PHP on the medial side of the hoof. Gap indicates excess growth and separation. (reference E)
Gauging flare with the PHP on the lateral side of the hoof. Looks good. (reference F)
Measuring wall and white line width with the PHP.

By keeping a measurement log of wall and white line thickness, you will be able to track and monitor any changes in integrity of the hoof wall and white line structure. This structure change can be a result of negative impact from diet and/or chemical toxins. (reference G)
Wall height should also be measured with the PHP on a regular basis and trimmed down to the desired height as needed. Depending on growth cycles, you may need to trim more frequently to keep a desired natural length. A natural wall height of 1/16 to 1/8 inch (.16 to .32 cm) above the sole at all times is effective. (reference H)

The hoof wall should be smooth with no flaring or distortion.
In this example (reference I), the toe is trimmed back to the hoof’s natural length. Most horses have a natural toe length between 3 and 3 ½ inches (7.6 and 8.9 cm) long. It may take many trims for a rehabilitating horse to achieve this natural length. Seek professional guidance!
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Addressing the excess growth on a timely basis ensures proper balance, hoof structure and ultimate performance.