foot of the horse 2

What structures does the “foot of the horse” include? Does this mean

just the hoof?

structures distal to the carpus and to the hock. this includes more

than the hoof.

2. In the fore and rear limb, give the common names of the bones

associated with the foot of the horse, from proximal to distal.

cannon and splint bones, proximal sesamoids, long pastern bone,

short pastern bone, navicular bone, coffin bone.

In the forelimb, give the technical names of the bones associated with

the foot of the horse, from proximal to distal.

metacarpal 3, metacarpals 2 and 4, proximal sesamoids, proximal

phalanx, intermediate phalanx, distal sesamoid, distal phalanx.

In the rear limb, give the technical names of the bones associated

with the foot of the horse, from proximal to distal.

metatarsal 3, metatarsals 2 and 4, proximal sesamoids, proximal

phalanx, intermediate phalanx, distal sesamoid, distal phalanx.

In the forelimb, give the letter and number designations (when

available) for the bones associated with the foot of the horse.

Mc3, Mc2 and Mc4, proximal sesamoids, P1, P2, distal sesamoid, P3.

In the rear limb, give the letter and number designations (when

available) for the bones associated with the foot of the horse.

Mt3, Mt2 and Mt4, proximal sesamoids, P1, P2, distal sesamoid, P3.

3. How many sesamoids does the distal leg of the horse have? Name them.

3 - 2 proximal sesamoids, 1 distal sesamoid (navicular bone).

Where are the proximal sesamoids located?

posterior fetlock joint

Where is the distal sesamoid located?

posterior coffin joint.

Is the navicular bone the proximal sesamoids or the distal sesamoid?

distal sesamoid

4. Give the common names of the 3 joints of the foot of the horse, from

proximal to distal.

fetlock joint, pastern joint, coffin joint.

In the forelimb, give the technical names of the 3 joints of the foot

of the horse, from proximal to distal.

metacarpophalangeal joint, proximal interphalangeal joint,

distal interphalangeal joint.

In the rear limb, give the technical names of the 3 joints of the foot

of the horse, from proximal to distal.

metatarsophalangeal joint, proximal interphalangeal joint,

distal interphalangeal joint.

5. Give the common name of the 2 bones that make up the pastern joint.

long pastern bone, short pastern bone.

Give the common name of the 2 bones that make up the coffin joint.

short pastern bone, coffin bone.

Give the common name of the 2 bones that make up the fetlock joint.

cannon bone, long pastern bone.

6. What is a tendon?

dense regular connective tissue connecting muscle to bone.

What is a ligament?

dense regular connective tissue connecting bone to bone.

7. Name the 3 major tendons and ligaments of the foot of the horse

covered in this class.

deep digital flexor tendon (DDFT), superficial digital flexor tendon

(SDFT), suspensory ligament.

Are these located anterior or posterior to the cannon bone?

posterior

In the cannon area of the distal leg, list the 3 major tendons and

ligaments in order from superficial to deep. Include skin and bone.

skin – SDFT – DDFT – suspensory ligament – cannon bone.

8. Where does the DDFT – deep digital flower tendon - insert?

on P3 – coffin bone.

Where does the SDFT – superficial digital flexor tendon - insert?

divides distal to fetlock, inserts on anterior P1 and P2

Where is the suspensory ligament located?

posterior cannon, between splint bones, deep to the DDFT, attaches

to proximal sesamoids, around fetlock, binds to anterior tendon.

9. Are the fetlock, pastern, and coffin joints synovial type joints?

yes

Do the DDFT and SDFT have individual synovial sheathes, or do they

share one?

share one

What is the common name for inflammation of the SDFT, DDFT, and/or

their common synovial sheath?

bowed tendon

10. Briefly describe the navicular bursa.

sac-like structure containing synovial fluid, located between DDFT

and navicular bone, reduces friction in that area.

11. What are the general functions of the hoof?

locomotion, shock absorption, support body weight.

12. What bones, or parts of bones, are located within the hoof?

part of P2 (short pastern bone), all of P3 (coffin bone) and distal

sesamoid (navicular bone).

13. What is the name of the soft tissue between the dead hoof wall and the

bone within the hoof?

corium

What is the corium?

modified dermis – the “quick”, it’s soft tissue

When referring to the hoof, what does sensitive mean?

has a nerve supply – if damaged, it will hurt.

What does vascular mean?

has blood vessels – if damaged, it can bleed.

Is the corium sensitive and vascular?

yes

14. Briefly describe the horny layer of the hoof.

is superficial to the corium, is attached to corium, is

insensitive and avascular.

What does avascular mean? Is the horny layer of the hoof avascular?

lacking blood vessels. yes - horny layer of the hoof is avascular.

What does insensitive mean? Is the horny layer of hoof insensitive?

lacking a nerve supply. yes - horny layer of hoof is insensitive.

15. List the specific structures of the hoof discussed in class.

hoof wall, periople, coronet, bars, laminae, sole, white line, frog,

digital cushion, collateral cartilages.

16. What is the hoof wall?

the part of the hoof that is visible when the foot is on the ground.

it is part of the horny, outside layer of the hoof. the other parts

of the horny layer are the superficial parts of the frog and sole.

List and briefly describe the regions of the hoof wall.

toe – front part of hoof wall. quarters – sides (medial, lateral).

heels – back parts (medial, lateral).

Briefly describe the basic layers of the hoof wall.

outer layers are composed of dense horny material.

inner layer – laminar layer – contains insensitive lamina, which

interlock with the sensitive lamina of the corium.

17. What is the periople?

thin layer of horn on superficial proximal hoof wall, extending from

coronet about 1 inch down.

Is the periople sensitive or insensitive?

insensitive

What happens to the periople when the hoof is soaked in water?

turns white.

18. What is the coronet, or coronary band?

junction of hoof and skin.

Where does the hoof wall grow from?

The coronet or coronary band

19. What are the bars of the horses foot?

ridges that extend inward and anteriorly from the hoof wall at the

heels, on bottom of foot.

20. Briefly describe the laminae of the horse’s hoof.

laminae are vertical ribbon-like layers. insensitive laminae inside

the hoof wall interdigitate with sensitive lamina on outside of corium.

What are primary laminae and secondary laminae?

primary laminae are the ones we can see when we look into a hoof.

secondary laminae are microscopic, and cover the primary

lamina.

As the hoof wall grows, which of these moves – the insensitive hoof

wall laminae, or the sensitive corium laminae?

hoof wall laminae.

What is the purpose of the laminae?

provide a large surface area for shock absorbing purposes.

21. What is the sole of the horse’s foot?

concave ground surface of hoof, between hoof wall and frog.

What part of the sole is insensitive? What part is sensitive?

the outer part is insensitive. deep to that is the sensitive sole

part of the corium.

22. What is the white line?

junction of sole and hoof wall on the bottom of the foot, visible

when the foot is trimmed.

What is the significance of the white line?

marks the boundary of sensitive and insensitive laminae.

When a horse is shod, should the nails be placed inside or outside of

the white line?

outside

What happens if nails are placed inside the white line?

lameness

23. What is the frog of the horse’s foot?

wedge shaped mass of soft horn, posterior, between bars, on ground

surface of hoof.

Does the frog have both an insensitive and a sensitive part?

yes

What is the “valley” in the middle of the frog called?

central groove, central sulcus, central cleft.

24. What is the digital cushion?

thick wedge of fibrous fatty tissue between frog and the DDFT.

What is the purpose of the digital cushion?

shock absorption

25. What are the collateral cartilages? How many does each hoof have?

two per hoof. cartilages attached to coffin bone, extend under skin

to a point proximal to the coronet, posterior part of foot.

Are the collateral cartilages normally palpable?

yes

What is the purpose of the collateral cartilages?

aid in shock absorption.

What is ossification of the collateral cartilage called?

sidebone

What is infection of the collateral cartilage called?

quittor

What does the word collateral mean?

on both sides

26. Briefly describe the stay apparatus of the horse.

the arrangement of tendons, ligaments, muscle and bones that permit

a horse to “sleep standing up”.

Is the stay apparatus present in the front limbs, rear limbs, or both?

stay apparatus is present in both front and rear limbs.

27. What is the reciprocal apparatus of the horse?

the arrangement of tendons, ligaments, muscle and bones that force

the hock and stifle joints to move in unison.

Is the reciprocal apparatus present in the front limbs, rear limbs, or

both?

reciprocal apparatus is present in rear limbs only.

When a horse flexes his stifle, what should his hock normally do?

flex

When a horse extends his stifle, what should his hock normally do?

extend

Can a horse normally flex his right stifle and extend his right hock

at the same time?

28. When a horse’s hoof strikes the ground, does blood flow into or out of

the hoof?

out of

When a horse’s hoof is lifted off of the ground, does blood flow into

or out of the hoof?

into

29. List the 4 main shock absorbing structures of the hoof.

frog, digital cushion, elasticity of hoof wall, collateral

cartilages.

30. What 2 structures do the hooves of cattle and sheep lack compared to

the hooves of horses?

frog, bars.

How many hooves (claws) per foot do cattle, sheep, and goats have?

two

Do cattle, sheep, and goats ever need their feet trimmed?

yes

Untrimmed feet in sheep can contribute to the development of what

condition?

foot rot

31. Why are we so concerned with lameness in horses?

directly affects their function as riding or working animals. they

can still be good pets.

32. What is laminitis?

inflammation of laminae of hoof.

What is the common term for laminitis?

founder

Is laminitis a common problem?

yes

Is laminitis more common in the front hooves or in the rear hooves?

front hooves

What are some of the causes of laminitis?

overfeeding grain, illness such as metritis, trauma.

What are the clinical signs of laminitis?

horse’s affected hooves are very painful. he may be down. if he is

up, he has his front hooves pointed in front of him, and acts like

he is “walking on eggshells”. the affected hooves may be warmer than

the non-affected hooves.

What can happen to the coffin bone of a horse with severe laminitis?

it can rotate, or drop through the sole.

33. Do most lamenesses occur in the hooves or in the rest of the leg?

hooves

Do more lamenesses occur in the front legs or in the rear legs? Why?

front legs – because they support more of the horse’s weight.