Understanding the 30 Degree hairline

And

  Using the Flexible Gauge

By Cheryl Henderson

Without x-ray eyes, what and where the internal structures are within the hoof can be seen on the outer capsules appearance.  Knowledge of angles, shape and length tell us what is happening, to the soft tissues, cartilage, bone and joints. Hidden behind the capsule wall and sole are potential damages, stress and bruising to corium’s, circulation, and parts of the hoof.    The assessment process will show what trimming is needed to balance the hoof and preserve the vital organ within, once you know what you are looking at.

The journey begins with confidence, because the natural baseline and fulcrum essential to mapping the hoof are consistent landmarks; both, providing data to the ABC trimming protocol. And understanding that the hairline at the quarters of a hoofed foot descends in a straight 30 degree angle, and that any deviation in this reflects what is being shifted, stressed and compromised within by the deformed or overgrown capsule.

The importance of the hairline to indicate balance within the hoof, lateral to medial and toe to heel, not only alerts us to problems that may or may not exist, but will show us if we trimmed the capsule correctly afterwards.  The hairline stays in a 30 degree descending angle to the ground surface and will not sag at the quarters even if the capsule was removed!  The hide is attached to the lateral cartilage and we know without the capsule the cartilage will stand on its own. Hairline changes from overgrown walls, long toes, and high heels present visual alterations in the fringing hair at the coronet of the capsule when the hoof is weightbearing on the ground. 

The hairline attached to the capsule reflects what is between the weight of the animal and the ground pressure.  The hairline will arch upward in a capsule that is long in the quarters or the angle can become increasingly parallel to the ground from a high heel.  When the hairline is steepening its angle past the 30 degrees from a long toe and crushed heel, this creates a negative axis within the coffin joint. The coffin bone tilts and becomes lower in the back then the front of the hoof.  

Another condition less seen to the hairline and the most alarming is when it drops behind the inside upper rim (coronet) of the capsule with sinking founder. In extreme cases you can place your finger slightly down behind the lip of the upper capsule. Remember the lateral cartilage is attached to the hide and the hide is attached to the capsule, so as the laminae of coffin bone and inner capsule wall break loose from each other the capsule shifts and the hairline will be pulled behind the coronet with the foundering parts within.

The significance of the unique laminae bonding between the coffin bone and capsule wall is enhanced further as it continues around to the heel quarters to securely attach the lateral cartilage to the inner capsule wall.  The lateral cartilage an interconnected and amazing part to the hoof is also attached to sole, bar corium, the navicular area, digital cushion, coffin bone and the short pastern bone to name some of the major parts within the hoof.  With all this interconnected tissue and bone attached and tucked behind the hard exterior of the hoof, knowing the importance of the hairline, we can visualize what is happening within.

The hairline tells us if there is good positioning in the coffin and pastern joints toe to heel and if there is no ground pressure jamming up in the quarters. It is not about the hairlines angle but all about the parts of the hoof that are attached and expressing if the capsule has levered  the internal structures from their natural and comfortable position, with pinching, tearing, stressing, and painfully bending of all parts in the hoof.  Not just those attached to the capsule wall and the lateral cartilage but, also the vital organ within.

The lateral and medial capsule wall at the quarters is equal in length side to side when the capsule bottom rim is wearing and trimmed correctly.  The coffin bone is attached to the capsule wall until the sole begins.   Imbalance created by a capsule wall that is extending past the sole is tilting the sole plane with one side now higher than the other when not wearing evenly.  Looking straight on to the capsule you can see tilting side to side if this is the case.  

The reality of how capsule imbalance affects the joints can be understood with this visual.  Think of the sole as a level platform which means the coffin bone and all the connected and linking parts above the sole are attached to this platform also.  Now on one side of the bottom of the platform insert a lift, representing overgrown wall extending past the sole plane.  The platform is now tilting; tilting the column of bones, stressing soft tissues, displacing joints being held hostage by the capsule wall.

Damages, pain and depression are now affecting the leg, body and spirit of the horse, having to negotiate the liability created from this imbalance.  There is an urgency to understand how dangerous capsule imbalance is because the joints are hinged and locked into a unique pattern, made to bend forward and back only not side to side. 

The sole once it grows past the live sole plane compacts in thin protective and callusing layers.  The capsule wall on the other hand continues to grow down past the natural sole level to create a lift and becomes the support and weightbearing of the animal.  Dr. Robert Bowker discovered that hooves peripheral loaded either by overgrown capsule wall or horseshoes begins to bifurcate at the upper area of laminae. 

The image of what happens in side to side imbalance is enough to scare you into timely trimming, now add to this the harmful effects of imbalance from toe to heel.  We all know how the teeter totter lifts up and down the passenger.  This same type of action can happen within the hoof capsule by tilting the coffin bone up and down from toe flare or high heels.

To grasp what is happening within the capsule you need to understand that the lateral cartilage is securely attached to the sole through the network of corium from its base.  These hair like projections of papillae corium create the hard keratinized bar horn.  Using the analogy of the teeter totter to how the bar, heel purchase and heel quarters lift up the back of the hoof we can begin to understand the importance of toe to heel balance.  Everything above this taller growing base in the back of the hoof is lifting and cramming none escaping parts within the hoof capsule and hide. 

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Imbalance diminishes the specialized shock absorption and expansion for hoof mechanism to work correctly.  The lateral cartilage is a massive part of the hoof, when lifted upward in the back; it also lifts up the back of the coffin bone it is attached too.  The coffin bone is now pressing downward on its rim, bruising or severing the circumflex artery, causing bone remodeling, disease and weakening the sole that generally becomes flattened.  The opposite imbalance from a hairline to high to one too low is the danger of harming not only the hoof but the tendons from the lower tilting back of the coffin bone.

Vital to all equines is learning to understand how damages and pain to the hoof and leg, can be prevented or helped by knowing and appreciating what the hairline is telling us, especially working with a founder.

 The capsule is only to protect this vital organ but with poor trimming practices can become lethal to the wellbeing of the hoof, leg and body.