Equine

Question 1

What are the main components of the horse foot?

Answer 1

bones
distal interphalangeal joint
medial & lateral hoof cartilages
extensor & flexor tendons, BV, nerves

Question 2

List the bones of the foot.

Answer 2

distal phalanx
distal part of middle phalanx
navicular bone

Question 3

Draw & label a schematic of an equine hoof.

Answer 3

add photo

Question 4

Describe the hoof wall.

Answer 4

highest @ toe

thickest @ toe

Question 5

Describe the periople.

Answer 5

external layer of hoof
thin soft horn near coronet
joins skin @ coronary band

Question 6

Describe the sole.

Answer 6

ventral - between wall & bars
concave
3-4mm @ circumference is weight bearing
slightly flexible

Question 7

Describe the white line.

Answer 7

junction between wall & sole

thin, soft, light horn

Question 8

Describe the frog.

Answer 8

limited weight bearing
heel expansion & shock absorption
has central groove & collateral sulci

Question 9

Describe the distal phalanx.

Answer 9

P3/pedal bone
interior of hoof capsule, suspended by interlocking laminae
palmar is concave

Question 10

Describe the middle phalanx.

Answer 10

P2

articulates with P3 = coffin joint

Question 11

Describe the navicular bone.

Answer 11

sesamoid

attached to P1 w/ navicular suspensory ligament & collateral sesamoidean ligaments

Question 12

Describe the coffin joint.

Answer 12

dorsal & palmar pouches

between P2, P3, navicular bone

Question 13

Describe the tendons & ligaments of the hoof.

Answer 13

deep digital flexor tendon
inserts on palmar surface of distal phalanx
common digital extensor tendon
inserts on extensor process of P3

Question 14

Describe the digital seasamoidean ligament.

Answer 14

connects navicular bone & P3

Question 15

Describe the navicular suspensory ligament.

Answer 15

suspend navicular bone from P1

Question 16

Describe the vascular supply to the hoof.

Answer 16

medial & lateral digital arteries (accompanied w/ viens) -> artery of distal cushion, coronal artery, artery of hoof wall, artery of coffin bone

Question 17

Describe the nerve supply to the hoof.

Answer 17

all arise from lateral & medial digital nerves

Question 18

Describe the histology of the hoof wall.

Answer 18

stratum externum: originates from periople, thin horn
stratum medium: supportive, rods of horn parallel to surface, produced by stratum basale & spinosum @ coronary groove
stratum internal: keratinized primary laminae & secondary laminae (interdigitate with laminae from corium)

Question 19

Describe the corium.

Answer 19

dermis equivalent of hoof
collagen
vascularized & innervated

Question 20

Describe the growth cycle of an equine hoof.

Answer 20

grows 6-7mm/month
full cycle = 6-12m
constant wear & exfoliation

Question 21

What is the hoof growth cycle influenced by?

Answer 21

heredity
diet
environment (avoid extreme dry/damp & ammonia)
farriery

Question 22

Describe a new born foal foot.

Answer 22

capped with soft unpigmented hoof
reduces damage to uterus
shed

Question 23

What is the normal hoof conformation?

Answer 23

dorsal hoof wall parallel to pastern axis
(HPA - hoof/pastern axis)
low angle = broken back
high angle = broken forward

Question 24

What is the main function of the forelimb?

Answer 24

weight bearing (60%)
shock absorption

Question 25

What is unique about the ulna in a horse?

Answer 25

fused to radius in adulthood

Question 26

List extensor tendons of the metacarpus.

Answer 26

Extensor carpi radialis (ECR) Common digital extensor tendon (CDE) Lateral digital extensor tendon (LDE)

Question 27

List the flexor tendons of the metacarpus.

Answer 27

Superficial digital flexor tendon (SDFT) Accessory ligament of the SDFT (ALSDFT) “superior check ligament”  proximal to the carpus Deep digital flexor tendon (DDFT) Accessory ligament of the DDFT (ALDDFT) “inferior check ligament” Suspensory ligament (SL)

Question 28

List the ligaments of the metacarpus.

Answer 28

collateral ligaments ligaments of the proximal sesamoid bones ligaments of the navicular bone and ungular cartilage

Question 29

Describe the suspensory ligament (metacarpal).

Answer 29

2 lobes with central fat-muscle bundle | prevents overextension of fetlock

Question 30

Describe the accessory ligament of the deep digital flexor tendon. metacarpal

Answer 30

continuation of the palmar carpal ligament fuses with DDFT prevents overextension

Question 31

Describe the deep digital flexor tendon. | metacarpal

Answer 31

passes over nivicular bone | inserts @ P3

Question 32

Describe the superficial digital flexor tendon. | metacarpal

Answer 32

emerges from carpal canal, then sub-q splits at P1 to medial & lateral inserts @ middle sputum on P2

Question 33

Describe the palmar annular ligament. | metacarpal

Answer 33

palmar @ fetlock maintain SDFT & DDFT, resist abaxial movement of sesamoids inserts on palmar aspects of proximal sesamoids

Question 34

Describe the navicular bursa. | forelimb

Answer 34

between flexor surface of navicular bone & dorsal border of DDFT

Question 35

List the nerves of the forelimb.

Answer 35

``` brachial plexus ulnar nerve median nerve musculocutaneus nerve radial nerve ```

Question 36

Describe the innervation of the distal forelimb.

Answer 36

palmar metacarpal nerves palmar nerves palmar digital nerves

Question 37

Describe the stay apparatus.

Answer 37

Medial patellar ligament locks over trochlear ridge of the femur = Fixation of the stifle Reciprocal apparatus ensures hock and stifle locked in unison = fixation of hock Suspensory and sesamoid ligaments, flexor tendons and accessory ligament = Fixation of the fetlock and phalanges

Question 38

List the equine vertebral equation.

Answer 38

C7, T18, L6, S5, Cd15-21

Question 39

List the flexor muscles of the neck. (superficial)

Answer 39

sternocephalic | brachiocephalic

Question 40

List the extensor muscles of the neck. (superficial)

Answer 40

rhomboid trapezious Splenius cervical serratus

Question 41

What is the function of the nuchal ligament?

Answer 41

support weight of head & neck | conserve elastic energy when head lowered to assist raising head

Question 42

List the deep muscles of the neck.

Answer 42

``` flexor: long muscle of head long muscle of neck scalenus extensor: semispinalis capitis longest muscle of head ```

Question 43

Describe lordosis.

Answer 43

Downward deviation of lumbar & distal thoracic spine giving horse a dipped back appearance

Question 44

Describe scoliosis.

Answer 44

Lateral deviation of parts | of the spinal column

Question 45

Describe kyphosis.

Answer 45

Upward deviation of spine giving horse | a hunched, camel-like appearance

Question 46

Describe the sacrum in a horse.

Answer 46

5 vertebra fused by 5y old soft tissue structures replace foraminae

Question 47

What's special about the synovial sacroiliac joint?

Answer 47

different cartilages for each surface of the synovial joint sacral - hyaline ilial - fibrocartilage

Question 48

Describe the effects of raising the neck.

Answer 48

cervicothoracic extension | relaxes the ligaments, brings the spinous processes back together and extends the thoracic spine

Question 49

Describe the effects of lowering the neck.

Answer 49

ligaments under tension, separates the thoracic spinous processes and flexes the thoracic spine

Question 50

How is the back extended?

Answer 50

T-L and L-S extension achieved by longissimus & spinalis & multifidus L-S extension Middle gluteal

Question 51

How is the back flexed?

Answer 51

T-L and L-S contraction of rectus & internal oblique L-S flexion contraction of psoas major & minor

Question 52

How is the back flexed laterally?

Answer 52

unilateral contraction of: iliocostal longissimus oblique abdominal

Question 53

How do you know a horse has back pain?

Answer 53

resists flexion of back | pain on palpation

Question 54

Where can you collect CSF?

Answer 54

atlantooccipital space | lumbosacral space