Chapter 9

Question 1

Give a sysnonym for each of the following terms: proximal phalanx, middle phalanx, distal phalanx, distal sesamoid bone, middle distal sesamoidean lig

Answer 1

• proximal ph=long pastern bone=P1
• middle ph=short pastern bone=P2
• distal ph=coffin bone=P3
• distal sesamoid bone=navicular bone
• middle distal sesamoidean ligament=oblique sesamoidean ligament

Question 2

Give a synonym for each of the following terms: palmar or plantar, interosseus tendon, superficial distal sesamoidean ligament.

Answer 2

• palmar or plantar=volar
• interosseus tendon=suspensory ligament
• superficial distal sesamoidean ligament=straight sesamoidean ligament

Question 3

What is de facto proximal sesamoidean ligament?

Answer 3

The interosseus tendon is actually the proximal sesamoideal ligament

Question 4

Which distal sesamoidean ligament spans over two joints?

Answer 4

Straight sesamoidean ligament

Question 5

Why are the (proximal) sesamoid bones prone to fracture?

Answer 5

• due to stress placed on ligamentous sys. when body weight places downward force on fetlock joint in rapid motion
• sesamoids caught between suspensory ligament and distal sesamoidean ligaments

Question 6

What is the meaning of plantigrade, digitgrade, unguligrade? Give examples of each.

Answer 6

• plantigrade=all of the foot (entire sole) is on ground; humans, bears
• digitigrade=stands on digital pads-camelids and carnivores
• unguligrade=stands on hoof; horses, cow, most ungulates

Question 7

What are the three parts of the wall, what are the bars?

Answer 7

• toe, quarters, and heel

- the bar is where wall reflected invward and back towards toe (at heel)

Question 8

What is the white line and how is it significant?

Answer 8

White line is the junction of the wall and sole. It is the spot where farriers place nails when shoeing.

Question 9

What is the: frog, heel, bulbs, and coronet?

Answer 9

• frog=wedge-shaped, horny prominence in the sole of horses’ hooves (the space between the bar)
• heel=caudal part of hoof
• bulbs=caudal aspect of heel
• coronet=junction between skin and hoof

Question 10

A hoof pick is used to clean maure and dirt out of the “bottom” of a horse’s foot. What deep groove(s) would the hoof pick be especially useful for?

Answer 10

-collateral sulci (paracuneal grooves) are deep grooves separating the bars from the frog that the hoof pick is especially useful for

Question 11

What produces the hoof wall and how does outgrowth of the wall affect its flexibility?

Answer 11

• long conical papillae in coronary band produce tubular horn which forms buk of hoof wall
• toe grows out slowly b/c it’s long part of wall and therefore is oldest part of hoof wall
• as hoof wall ages it becomes less moist and therefore less flexible

Question 12

What is the structure and function of the equine collateral cartilages of the coffin bone?

Answer 12

-collateral cart. are attached to wings of coffin bone and not to hoof. When foot strikes ground the digital cushion expands and pushes the collateral cartilages out so that veins are compressed forcing blood to move up leg

Question 13

Why is the navicular bone so named?

Answer 13

It is shaped like a boat.

Question 14

What are the principle attachments of the navicular bone?

Answer 14

Attached to long pastern by suspensory ligaments of navicular bone and distal sesamoidean ligament bands navicular to coffin bone

Question 15

What is on the dorsal and palmar surface of it?

Answer 15

• dorsal suface in contact with palmar surface of coffin joint
• palmar surface in contact with navicular bursa

Question 16

What is the main structure putting pressure of the navicular bursa?

Answer 16

Deep flexor tendon can put pressure on navicular bursa and may cause pain. A long toe will drop heel causing more pain due to tendons being pulled tight b/c of increased extension. An enlarged heel will reduce pain due to increased flexion.

Question 17

What is the structure and significance of the digital cushion?

Answer 17

• similar to dig. pad in dog; made of collagen, adipose tissue, and hyaline cart.
• becomes squashed when weight is put on foot and compresses vein between hoof wall and cartilages and squeezes blood out of venous spaces that lie between skin/cart

Question 18

Compare and contrast bovine foot w/ that of horse.

Answer 18

cows are diff. form horses b/c:

• bear weight on heel and wall; bov. heel separate from wall (part of wall in equ.-volar third); bov. heel homologous to bulbs of eq. heel
• bov. feet have wall and sole (no homol. of frog or collateral cartilages)

Question 19

Compare and contrast bovine foot w/ that of horse (cont.)

Answer 19

cows are diff. from horses b/c/:
-laminae lack secondary (microscopic) laminae (prob. relates to fact that in horse wall bears all wgt. but in cattle >half of weight is borne by wall-thus laminitis in cattle not as painful)