The Equine Distal Limb

Question 1

canon bone aka?

Answer 1

metacarpal/metatarsal bone III

Question 2

long pastern aka?

Answer 2

proximal phalanx

Question 3

short pastern aka?

Answer 3

middle phalanx

Question 4

navicular aka?

Answer 4

distal sesamoid bone

Question 5

pedal bone aka?

Answer 5

coffin or distal phalanx

Question 6

there are distal sesamoid bones and?

Answer 6

proximal sesamoid bones

Question 7

what joints are found in the distal limb of horse?

Answer 7

MCP/MTP
PIP
DIP

Question 8

MCP/MTP/fetlock joint?

Answer 8

metacarpophalangeal/metatarsaophalangeal joint

Question 9

PIP joint?

Answer 9

Proximal interphalangeal joint aka
pastern joint

Question 10

DIP joint?

Answer 10

distal interphalangeal joint; coffin joint

Question 11

five parts of the hoof dermis?

Answer 11

perioplic
coronary
lamellar
solar
frog

Question 12

dermis =

Answer 12

corium

Question 13

subcutis =

Answer 13

coronary cushion and digital cushion

Question 14

what is the breakdown of the ligaments in horse distal limb?

Answer 14

collateral ligaments
palmar ligaments
sesamoidean ligaments

Question 15

how can diagnosis be narrowed down to individual ligaments?

Answer 15

diagnostic perineural anaesthesia, ‘nerve blocking’

Question 16

what are the two palmar ligaments?

Answer 16

palmar axial and abaxial ligaments (PIP)

Question 17

what are the annular ligaments?

Answer 17

palmar (PAL) over MCP
proximal digital over prox P1
distal digital over distal P1

Question 18

what do the palmar and annular ligaments do?

Answer 18

keep flexor tendons in place (retinaculum)
tendon sheaths pass deep to the annular ligaments

Question 19

what are the proximal sesamoidean ligaments?

Answer 19

short
collateral
oblique
cruciate
intersesamoidean
straight
AND distal (navicular) sesamoidean ligaments as well

Question 20

flexor tendons?

Answer 20

suspensory ligament (aka interosseus muscle)
superficial digital flexor tendon (SDFT)
(and its associated proximal check ligament)
Deep digital flexor tendon (DDFT)
(and its associated distal check ligament)

Question 21

extensor tendons?

Answer 21

common and lateral digital extensor tendons
common inserts on extensor process of distal phalanx

Question 22

suspensory ligament?

Answer 22

tendinous remnants of the interosseus muscle
palmar aspect MC3
originates from distal row of carpal bones and proximal MC
inserts upon abaxial aspect proximal sesamoids
extensor branches connect with common digital extensor

Question 23

deep digital flexor tendon (DDFT)?

Answer 23

inserts upon palmar distal phalanx
passes over palmar aspect navicular bone
distal ‘check’ ligament anchor tendon to proximal MC bone

Question 24

distal check ligament?

Answer 24

AKA the accessory ligament of the DDFT
attaches the DDFT to the palmar carpal ligament
Stiffens the tendon
Less tension is placed on the DDF muscle
Hindlimb equivalent is less developed

Question 25

deep digital flexor tendon (DDFT)?

Answer 25

inserts upon palmar distal phalanx passes over palmar aspect navicular bone distal 'check' ligament anchors tendon to proximal MC bone

Question 26

superficial digital flexor tendon (SDFT)?

Answer 26

closely associated with DDFT inserts either side of proximal interphalangeal joint flattens and wraps around the DDFT at level of prox. sesamoid bones - the manica flexoria Divides and allows emergence of DDFT at mid-level of proximal phalanx

Question 27

bursae and sheaths: cushions and sleaves?

Answer 27

a cavity lined with synovial membrane either forms a cushion (A) or sleave (B)

Question 28

Bursae of the distal limb?

Answer 28

navicular bursa on palmar aspect of navicular bone others too but less significance

Question 29

tendon sheath of distal limb?

Answer 29

DDFT/SDFT share the digital tendon sheath digital sheath starts proximal to MCP, terminates mid-level of middle phalanx Lubricate passage of tendons as they slide against neighbouring structures and against each other potential site of damage and infection

Question 30

what does the navicular apparatus consist of?

Answer 30

navicular bone collateral sesamoidean (navicular) ligaments Distal sesamoidean impar (navicular) Navicular bursa Deep digital flexor tendon (DDFT) Distal digital annular ligament

Question 31

functions of navicular apparatus?

Answer 31

navicular bone displaces DDFT away from DIP - increases leverage Bursa cushions both the DDFT and the navicular bone

Question 32

sensory innervation of palmar aspect of distal limb?

Answer 32

medial and lateral palmar nerves alongside SDFT branch at MCP into dorsal branches and palmar digital nerves palmar metacarpal nerves - from deep branch of lateral palmar nerve Palmar digital nerves: innervate heel of foot

Question 33

sensory innervation of dorsal aspect of distal limb?

Answer 33

dorsal branches of digital nerves: innervate toe of foot additional dorsal foot innervation in hindlimb by dorsal metatarsal nerves

Question 34

what is diagnostic anaesthesia - 'nerve blocking'?

Answer 34

used to locate a source of pain/lameness sensory nerves are blocked in a distal to proximal direction until lameness disappears

Question 35

what happens during diagnostic anaesthesia?

Answer 35

local anaesthesia injected close to nerve locations (perineural anaesthesia) skin and deep tissues distal to the site will be desensitised

Question 36

give examples of diagnostic anaesthesia?

Answer 36

palmar/plantar digital nerve block abaxial sesamoid nerve block low 4 point nerve block

Question 37

what nerves are blocked during a palmar/plantar digital nerve block?

Answer 37

medial and lateral palmar/plantar digital nerves

Question 38

which region of the foot will be blocked if the medial and lateral palmar/plantar digital nerves are blocked?

Answer 38

heel

Question 39

if the medial and lateral palmar/plantar digital nerves are blocked, what will they block pain from?

Answer 39

from sole, navicular bone, palmar fractures of distal phalanx and bulbs

Question 40

what nerves are blocked for an abaxial sesamoid nerve block?

Answer 40

medial and lateral palmar/plantar digital nerves + dorsal branches

Question 41

which region of the foot will be blocked if the medial and lateral palmar/plantar digital nerves + dorsal branches are blocked?

Answer 41

whole hoof (up to coronary band)

Question 42

what will the nerve blockage of medial and lateral palmar/plantar digital nerves + dorsal branches block pain from?

Answer 42

PIP, distal sesamoidean ligaments, toe, heel structures

Question 43

what nerves are blocked during a low 4 point nerve block?

Answer 43

medial and lateral palmar/plantar metacarpal/metatarsal nerves medial and lateral palmar/plantar nerves

Question 44

during a low 4 point nerve block - which region of the foot will be blocked?

Answer 44

entire foot up to MCP/MTP

Question 45

the low 4 point will block pain from?

Answer 45

all structures of the foot SDFT/DDFT up to MCP insertions of suspensory ligament

Question 46

how do you diagnose pain in the toe region?

Answer 46

start off w/ digital nerve block - block out heel abaxial sesamoid nerve block - now it's blocked out as toe is now included in nerve block we can tell it was toe as toe wasn't covered in first one

Question 47

suspensory ligament and check distal ligament are actually...

Answer 47

tendons (I think)