AGR 510 Equine Foot and Stay Apparatus

List the horses bones of the digit from proximal to distal

-Cannon bone (Split bones)

-P1 Long Pastern

-P2 Short Pastern

-P3 Coffin Bone

What two bones make up the Fetlock joint?

Long Pastern (P1) and the Cannon bone

What two bones make up the Pastern joint?

Long and Short Pastern bones

What two bones make up the Coffin joint?

Short Pastern and the Coffin bone

What are the two proximal sesamoid bones?

palmar/plantar surface of the fetlock

What is the Navicular bone?

-Distal sesamoid bone

-Unpaired; palmar/plantar aspect of the coffin joint

What causes sidebone? What can it lead to?

Trauma/ossification to the ungual cartilages

Can lead to lameness

What is "Quittor"?

The name given to infection of the ungual cartilage

What does the Coffin bone (P3) feature in terms of processes and cartilage?

features medial and lateral palmar/plantar processes with ungual cartilages attached

What is the coronary band?

Where the haired skin changes to hoof

What is the Hoof Wall?

the visible portion of the hoof; composed of horny material that must be trimmed

What is the Perioplic corium?

Found at the coronary band; thin layer of the tissue that produces the thin waxy periople on the surface of the hoof

What is the Sole?

concave keratinized plate attached to the palmar/plantar surface of P3

-The entire ground surface, not occupied by frog or hoof wall

What is the White line?

-space between the two laminae

-Appears white of yellow

-Used to drive nails for shoes; not sensitive if done correctly

What is the Frog?

specialized, wedge-shaped pad in center and heel region

-Compression is important for blood flow

-Demarcated by sulci

What is the Digital Cushion?

Thick, fibrofatty pad deep within the frog

What is the Coronary Corium? What does it do?

-highly vascular and sensitive layer of connective tissue directly beneath the coronary band at the top of the hoof; like the "Quick" of a dog or cat nail

-Generates the hoof wall

What is the Laminar Corium: Sensitive Laminae?

microscopic, highly vascular, nerve dense tissue layers that cover the coffin bone

What is the Epidermal Laminae: Insensitive Laminae?

rigid, overlapping sheets of tissue attached to the inside of the hoof wall. No nerves or blood supply

How does the Epidermal Laminae and the Laminar Corium suspend the coffin bone?

The two layers interlock tightly to form a "Velcro-like" bond that suspends the coffin bone within the hoof

What is Laminitis?

Inflammation of the laminae

-The hoof is a closed space, so the swelling and pain can become unbearable

What can Laminitis cause?

detachment of sensitive and insensitive laminae

What causes Founder?

When the detachment of the sensitive and insensitive laminae he coffin bone (P3) rotates downward

What is the Suspensory ligament?

runs parallel to the cannon bone on the palmar/plantar aspect. Strong supportive mechanism for the fetlock

What are the Distal Sesamoidean Ligaments?

Two straight, two oblique and the cruciate sesamoidean ligaments

What does the Distal Sesamoidean Ligaments connect?

Proximal sesamoid bones to the Long and short pasterns (P1 + P2)

What are the Medial and Lateral collateral ligaments?

Ligaments of the fetlock, pastern and coffin joints

What is Navicular Disease?

inflammation of the bursa between the navicular bone and the deep digital flexor tendon

What are some common causes of forelimb lameness?

-Bursitis

-Erosion of the articular cartilage of navicular bone

-Adhesions between the DDFT and the navicular bone

(could have a hereditary component or how the horse has been trimmed)

What are the functions of the foot?

-Aids in locomotion

-Provides support for standing

-Single toe is highly adapted to aid in speed and gait efficiency

-Absorbs concussion and aids in venous circulation (frog and digital cushion

-Stores energy in its elastic tissue

-Provides leverage for the muscles attached

-The ability to sleep while standing is based on its ligamentous structures

What is the Stay Apparatus?

A specialized system of tendons, ligaments and muscles in horses and other large mammals that "lock" major leg joints in place. Allows the animal to rest with almost no muscular effort.

What is the Stay Apparatus for the thoracic limb?

Continuous ligamentous connection from the scapula, across the elbow to the proximal radius; then proximal metacarpus for stability

What is the Fetlock supported by on the palmar aspect?

The Suspensory ligament

What is the Deep digital flexor accessory ligament?

Carpal or Distal Check Ligaments

What could injury to the flexor tendons lead to?

Dropping of the fetlock

What tendon is the only one resisting hyperextension of the coffin joint?

Deep digital flexor

What happens when the Fetlock drops to the ground?

There's a complete fracture of the sesamoids or the suspensory ligaments are transected

-There is no fixing this

What are the two mechanisms that keep the stifle and hock from flexing?

-Locking of the patella

-Reciprocal apparatus

How does the Locking of the patella work?

Over the medial ridge of the trochlea of the femur

How does the Reciprocal apparatus work?

Hock and stifle will always flex and extend in unison

What is the upward fixation of the patella?

The patella locks unintentionally above the medial ridge of trochlea

What causes upward fixation of the patella?

-Confirmation

-Neuromuscular issue

How can you treat Upward fixation of the patella?

Exercise or surgery