The best way to tell the position of the Distal Phalanx, or P3, is to have a lateral/medial radiograph of the hoof.  Usually, the foot will have to be placed on a block to get the x-ray beam parallel to the base of the bone.

Without an x-ray, you can look at the slope of the upper one third of the hoof wall, just below the coronet.  If the wall is tightly adhered to P3, this will give you an accurate angle for the hoof wall and bone.  Ideally the angle of the base of the coffin bone is 5-10˚with the ground.  Ideally the angle of the dorsal front surface of P3 is parallel to the slope of the pastern.

You can also run your finger down the front of the pastern.  If your finger slides easily over the coronary band, the bone is in a normal position.  If your finger stops or falls into a crevice at the hair line, the bone has sunk within the hoof capsule.  Another indication that the bone has sunk, is the dropping of the sole.  If the sole is flat, that indicates the bone has sunk down due to a weakened or destroyed laminar attachment.  This is the case in foundered feet.

The best way to understand what is inside the horse’s hoof is to study the anatomy of the equine foot.  A good resource is The Principles of Horseshoeing (P3).  Until you have studied enough to know the foot backwards and forwards and can visualize what is located within the hoof, you should be dealing only with sound backyard horses and referring other cases needing more expertise to a qualified farrier.

It is interesting to see the students’ progress at our school.  At first, some are hesitant to even begin trimming the hoof.  With the sequential learning we provide at Butler Professional Farrier School, they each gain confidence as they learn to visualize the interior of the horse’s foot.  We just graduated eight students this week, and the work they did in their final exams showed their understanding of equine foot anatomy.