Forelimb anatomy (Yr 1)

Question 1

what is the weight bearing digit of horses?

Answer 1

3rd

Question 2

what is the function biceps brachii?

Answer 2

extends shoulder and flexes elbow

Question 3

what part of the stay apparatus connects to the biceps brachii?

Answer 3

lacertus fibrosis

Question 4

what is the lacertus fibrosis?

Answer 4

fibrous extension of the biceps brachii that inserts onto the proximal third metacarpal

Question 5

what are the carpal bones present in horses?

Answer 5

radius, intermediate, ulna, accessory
2, 3, 4 (3rd is largest)

Question 6

what joint of the carpus has the most movement?

Answer 6

antebrachial-carpal joint

Question 7

what joint of the carpus has the least movement?

Answer 7

carpometacarpal joint

Question 8

what structures support the carpus?

Answer 8

collateral ligaments
palmar fibrocartilagenous plate (check ligament origin)

Question 9

what forms the carpal canal?

Answer 9

palmar fibrocartilagenous plate
palmar retinaculum
accessory carpal bone

Question 10

what passes through the carpal canal?

Answer 10

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

Question 11

what does the tendon sheath cover?

Answer 11

deep digital flexor tendon
superficial digital flexor tendon

Question 12

what is the third metacarpal bone known as?

Answer 12

cannon bone

Question 13

what are the second and fourth metacarpal bones known as?

Answer 13

splint bones

Question 14

what is the palpable section at the bottom of the splint bones known as?

Answer 14

button

Question 15

what connects the cannon bone to the splint bones?

Answer 15

fibrous joint that mineralises with age

Question 16

what is the proximal phalanx known as?

Answer 16

long pastern bone

Question 17

what is the middle phalanx known as?

Answer 17

short pastern

Question 18

what is the distal phalanx also known as?

Answer 18

pedal or coffin bone

Question 19

what tendon attaches to the coffin bone?

Answer 19

common digital extensor tendon
deep digital flexor tendon

Question 20

why is the dorsal surface of the coffin bone striated?

Answer 20

due to blood vessels and hoof attachment

Question 21

how many centres of ossification do the metacarpal bones have?

Answer 21

third (cannon) has 2
second/fourth (splints) have 2

Question 22

how many centres of ossification do the phalanges have?

Answer 22

proximal - 2
middle - 2
distal - 1

Question 23

what is the distal sesamoid called?

Answer 23

navicular

Question 24

where is the navicular bone located?

Answer 24

palmar aspect of the distal interphalangeal joint

Question 25

what tendon runs over the navicular bone?

Answer 25

deep digital flexor tendon

Question 26

what is the metacarpophalangeal joint known as?

Answer 26

fetlock

Question 27

what bones form the fetlock joint?

Answer 27

third metacarpal and proximal phalanx

Question 28

what features limit the metacarpophalangeal joint to just flexion and extension?

Answer 28

saggital ridge on third metacarpal along with the groove on the proximal phalanx

Question 29

where is the suspensory ligament found?

Answer 29

runs from the palmar third metacarpal between the splint bones and then attaches to the common digital extensor tendon

Question 30

what are the structures that support the carpal joint?

Answer 30

intersesamoidean ligaments collateral sesamoidean ligaments

Question 31

what are the four sesamoidean ligaments supporting the carpus?

Answer 31

cruciate short oblique straight

Question 32

what is the proximal interphalageal joint known as?

Answer 32

pastern joint

Question 33

what is the distal interphalageal joint known as?

Answer 33

coffin joint

Question 34

what structures coordinate movement of the distal interphalangeal joint?

Answer 34

common digital extensor tendon deep digital flexor tendon

Question 35

what ligaments attach to the navicular bone?

Answer 35

collateral (to proximal phalanx) impar (to distal phalanx)

Question 36

what separates the distal interphalangeal joint from the navicular bursa?

Answer 36

impar ligament

Question 37

what is the mineralization of the medial/lateral cartilages of the distal phalanx called?

Answer 37

sidebone

Question 38

what are the extensor tendons of the forelimb?

Answer 38

common digital extensor (joint by suspensory ligaments) lateral digital extensor

Question 39

what are the flexor tendons of the forelimb?

Answer 39

superficial digital flexor tendon deep digital flexor tendon

Question 40

what ligament attaches to the deep and superficial digital flexor tendons?

Answer 40

accessory check ligament

Question 41

what does the superficial digital flexor tendon insert onto?

Answer 41

middle phalanx

Question 42

what are the layers starting with skin of the dorsal metacarpal region?

Answer 42

skin superficial digital flexor tendon deep digital flexor tendon accessory check ligament suspensory ligament

Question 43

what is the function of the annular ligaments?

Answer 43

hold deep and superficial digital flexor tendons against the bone

Question 44

what are the two main branches of the median and ulnar nerves (they combine distal to carpus)?

Answer 44

palmar metacarpal nerves (supply dorsal aspect of the digit) palmar nerves (becomes palmar digital nerve)

Question 45

what are the anatomical aspects of the solar surface of the hoof?

Answer 45

frog (rubbery wedge between the bars) bars of heel sole (shouldn't contact ground) white line walls (weight bearing) central and collateral sulcus

Question 46

what is the periople?

Answer 46

surrounds the coronary region providing a waterproof layer

Question 47

what is the function of the digital cushion?

Answer 47

provide shock absorption and protection to DDFT, distal phalanx, navicular bursa and navicular bone

Question 48

what ere the functions of the lateral cartilages of the hoof (distal phalanx)?

Answer 48

shock absorption

Question 49

what is the function of the coronary band?

Answer 49

produce epidermis in the form of keratin tubes that extend distally

Question 50

what is the weight bearing surface in horses?

Answer 50

hoof wall

Question 51

what is the dermis of the hoof made from?

Answer 51

vertical ridges (laminae) that attach to the distal phalanx

Question 52

how does a horse weight bear?

Answer 52

frog contacts ground first and passes forces into digital cushion and lateral cartilages hoof wall then contacts the floor and transfers weight via laminae to the distal phalanx