The Weight Bearing
Function Of The Sole
“Anatomical Evidence”
Michael T. Savoldi
Farrier Emeritus
Resident Farrier (Retired)
W.K. Kellogg Arabian Horse Center
Farrier Science Instructor
Animal & Veterinary Science
California State Polytechnic University,
Pomona, California
M. T. Savoldi
Equine Research Center
Shandon CA. USA
1
Bone Position
Using the arch of the sole as a
means to Identify the plane of
the PIII bone
M. T. Savoldi
Equine Research Center
Shandon CA. USA
2
Sole
Bar And Lamina
Top Line
Sole/Frog Ridge
Sole Angle
Sole Body
Leading Edge Of Sole
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Sole Connection To Wall
3
Arch Of The Foot
Heel Arch
Arch Mid-Section
Toe Arch
Good Arch
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Equine Research Center
Shandon CA. USA
4
Good Arch
Strong & Well Developed Arch
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Equine Research Center
Shandon CA. USA
Arch Is Holding Bone Position
5
Bone Position
Wall Removed
PIII
PIII
Sole Dermas
Medial
Sole
Sole connection to wall
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Lateral
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Good Arch
Medial Arch
Lateral Arch
Arch of sole body
Bone position on arch
Space between bone and sole
Note: Leading edge of PIII is above sole connection to 7wall
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Good Arch
Bone Position
Lateral
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Equine Research Center
Shandon CA. USA
Medial
Space between bone and sole
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Bone Position On Bar
Lateral
Medial
Top line of bars
Bone position on bar
Space between bone and sole
M. T. Savoldi
Equine Research Center
Shandon CA. USA
9
Bone Models To The Arch
Lateral Arch
Arch
Medial Arch
Bone position on arch
Bone modeling to arch
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Equine Research Center
Shandon CA. USA
10
Bone Position
Bone centered on sole
Arch of sole body
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Good spacing between
bone and wall
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Bone Position
Good Arch
Bone Position On Arch
PIII Bone
Negative Plane Toe Area
Weak Arch Toe Area
PIII Bone
Close Proximity
To Plane Of
Horizon
Weak Arch Mid-Section
PIII Bone
Negative Plane Heel Area
Week Arch Heel Area
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Equine Research Center
Shandon CA. USA
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Note: Uniform Sole Thickness (UST) Was Used As A Standardized Foot Trim
Heel Arch
Good
Arch
Strong Heel Arch
Bone Position
Weak Toe Arch
Toe Arch Flatting Not
Supporting Bone Position
Angles Of The Sole Will Position PIII Bone In An Upright Angle
M. T. Savoldi
Equine Research Center
Shandon CA. USA
13
Larger Palmar Angle
High arch with sunk anterior (front) part of the sole. The radiograph in C
is that of a live horse with similar conformation to the sole and pedal
M. T. bone
Savoldi
of A, B.
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Equine Research Center
Shandon CA. USA
Movie PIII In Motion
Toe Area
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Equine Research Center
Shandon CA. USA
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M. T. Savoldi
Equine Research Center
Shandon CA. USA
Toe sink
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No sole pack
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Equine Research Center
Shandon CA. USA
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Movie PIII In Motion
• Movie 1 (No orthotic)
• Movie 2 (With orthotic)
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Equine Research Center
Shandon CA. USA
Two stage silicone putty
18
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Equine Research Center
Shandon CA. USA
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With sole pack
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Equine Research Center
Shandon CA. USA
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Stabilizing Movement Of PIII
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Equine Research Center
Shandon CA. USA
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Arch Collapsing
Good
Bone Position
Arch Leveling
Wide Flat Foot Developing With Weak Arch
PIII Bone Will Be In Close Proximity To Plane Of Horizon
It has sole depth, it doesn’t have an arch.
Pathology to the mid section to the bars, crushed heels, dropped soles along
the leading edge of the leading edge of the p3 bone
M. T. Savoldi
Equine Research Center
Shandon CA. USA
22
Flat Footed
Flat sole. The radiograph in C is that of a live horse with similar
conformation to the sole and pedal bone of A, B.
M. T. Savoldi
Equine Research Center
Shandon CA. USA
23
Morph Flat Foot
• Single radiograph taken before
without orthotic (arch support) and
after with orthotic.
• Foot trimmed to a horizontal plane
excess sole not removed
• Both radiograph were then morphed
together to show the effects of the
orthotic
M. T. Savoldi
Equine Research Center
Shandon CA. USA
24
M. T. Savoldi
Equine Research Center
Shandon CA. USA
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Toe Arch
Good
Weak Heel Arch
Bone Position
Arch
Strong Toe Arch
Heel Arch Flatting Not
Supporting Bone
Position
PIII Bone Will Develop A Negative Plane Heel Area
M. T. Savoldi
Equine Research Center
Shandon CA. USA
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Negative Palmar Angle
The bone position is in a negative plain.
More commonly seen in hind feet.
Sole sunk in the caudal (back) area. The radiograph in C - is that of a
live horse with similar sole and pedal bone conformation to that of A, B.
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Equine Research Center
Shandon CA. USA
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Toe lift
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Equine Research Center
Shandon CA. USA
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Movie PIII In Motion
Negative Plane Heel Area
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Equine Research Center
Shandon CA. USA
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Morph Negative Plane
• Single radiograph taken before
without orthotic (arch support) and
after with orthotic.
• Foot trimmed to a horizontal plane
excessive sole not removed
• Both radiograph were then morphed
together to show the effects of the
orthotic
M. T. Savoldi
Equine Research Center
Shandon CA. USA
30
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Negative plane
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Pathology Based On the Plane Of The Pedal Bone (PIII)
Good Arch
Weak Arch Toe Area
Stress To Soft Tissue
Normal Bone
Bone Position On Arch
PIII Bone
Upright Angle
Flat Toe
Sole Thinning
Weak Arch Mid-Section
Stress To Soft Tissue
Degeneration To PIII
PIII Bone
Close Proximity
To Plane Of
Horizon
Bone Reabsorbing
Flat Foot
Bar Shifting Damage To The Lamina
Weak Arch Heel Area
Stress To Soft Tissue
PIII Crushing Bars
Stress Bump
PIII Bone
Negative Plane
Flat Heel
Sole Thinning
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Degeneration To PIII
Note: Uniform Sole Thickness (UST) Was Used As A Standardized Foot Trim
32
Bone Remodeling
Good bone position
Bone Position
PIII and sole
Sole body
Medial
Bone sinking into sole
PIII should be above the sole edge
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Equine Research Center
Shandon CA. USA
Lateral
Angle of sole body
Medial/Lateral arch
33
Bone Position
Good bone position
Good arch
PIII and sole
Load affects arch
Bone sinking into sole
PIII should be above the sole edge
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Equine Research Center
Shandon CA. USA
Angle of sole body
34
Bone Position
PIII below sole edge
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Equine Research Center
Shandon CA. USA
PIII sinking into sole
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Bone Position
Damage to soft tissue caused by bone sinking into sole
PIII sinking into sole
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Equine Research Center
Shandon CA. USA
Weight bearing damage to the sole
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Tissue Movement
Close observation reveals a shift in tissue
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Equine Research Center
Shandon CA. USA
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Area Of Damage
Soft tissue damage
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Equine Research Center
Shandon CA. USA
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Effects Of Weight Bearing
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Equine Research Center
Shandon CA. USA
A deviation in the frog sole connection
39
Collapsed Bar
Damage to the laminae
Medial
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Equine Research Center
Shandon CA. USA
Lateral
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Effects Of Body Weight
Bar
Sole
Bone position descending pressing into the bar and sole
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Equine Research Center
Shandon CA. USA
41
Bone Models To The Angles Of
The Sole
Stress bump developing in bone
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Equine Research Center
Shandon CA. USA
Deviation in the sole
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Bone Models To Pressure
3
3
2
1
Bone loss
1) Stress bump DDFT
2) Stress bump Impar ligament
3) Stress bump Palmar Process
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Equine Research Center
Shandon CA. USA
Stress bump Palmar Process
43
Internal Load
Deep digital flexor tendon (DDFT)
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Equine Research Center
Shandon CA. USA
Navicular bone
44
Motion Bar Movement
Load 5 & 6
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Equine Research Center
Shandon CA. USA
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M. T. Savoldi
Equine Research Center
Shandon CA. USA
46
M. T. Savoldi
Equine Research Center
Shandon CA. USA
47
Pathology Navicular Bone
Stress caused by unequal loading
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Stress area located above bar
48
Pathology Navicular Bone
Stress area located above bar
Erosion caused by movement of DDFT
M. T. Savoldi
Equine Research Center
Shandon CA. USA
49
Pathology Navicular Bone
Weight bearing pressure on bone
Unilateral
Bilateral
Location of stress above bar
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Equine Research Center
Shandon CA. USA
50
Pathology To Sole
• Bar/Sole abscess
• Crushing of the bar
• Damage to the soft tissue (dermas),
lamina, bar, and sole
M. T. Savoldi
Equine Research Center
Shandon CA. USA
51
Pathology To Sole
Trimming alone cannot prevent pathology to the sole
Bar shoe offers little support for sole body
Bar/Sole abscess
M. T. Savoldi
Equine Research Center
Shandon CA. USA
Crushing of the bar
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Pathology To Soft
Tissue/Sole
Bar, Lamina, Sole
Soft tissue
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Equine Research Center
Shandon CA. USA
Bar, Lamina, Sole
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DDFT Insertion To The
Navicular Bone
Severe damage to navicular bone
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Equine Research Center
Shandon CA. USA
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DDFT Insertion To The
Navicular Bone
Impar ligament
Deep Flexor Tendon (DDFT)
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Equine Research Center
Shandon CA. USA
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Severe damage to navicular bone
DDFT Insertion To The
Navicular Bone
Deep Flexor Tendon (DDFT)
M. T. Savoldi
Equine Research Center
Shandon CA. USA
56
Severe damage to navicular bone
Conclusion
• Weight bearing affects on the sole
quite often produce sore feet
• Because of its location the trauma to
the mid-section is often referred to
as navicular disease but in reality it
is very often soft tissue damage
• Stabilizing bone movement as a
preventive measure can reduce wear
in this area
M. T. Savoldi
Equine Research Center
Shandon CA. USA
57
Thank You
M. T. Savoldi
Equine Research Center
Shandon CA. USA
M. T. Savoldi
Equine Research Center
Shandon CA. USA
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