Pelvic Limb VII Flashcards
The equine foot includes?
epidermal hoof and all structures contained within.
Where do horses bear all of their weight?
hoof walls
Other ungulates (besides horse) bear weight on…
hoof walls and tissues of sole of foot
Components of epidermis of foot?
wall, sole and frog.
Epidermis of foot equals?
hoof
Epidermis sensitive or insensitive? Produced by?
insensitive; Germinal epithelium
Dermis is also called? Sensitive or insensitive? Function? What does it not do?
Corium
Sensitive
Provide nutrition to epidermis
Does not produce the epidermis
Is the dermis of the foot also continuous with the skin of the limb?
Yes
Perioplic corium fits into the ________ groove.
perioplic
Coronary corium fits into the ________ groove.
coronary
Hoof wall divided into?
toe, quarter, heel
Bars of hoof wall lie adjacent to the …
collateral grooves of the frog
Where does heel turn to become bars?
angle of the wall/sole
Components of the frog?
apex, two crura, a central groove, deep collateral groove
On the inner surface of the hoof the central groove is mirrored as the __________.
spine of the frog
Three major layers of the hoof wall?
Stratum externum, medium, internum
Stratum externum also called?
periople
Stratum externum produced by the
perioplic GE covering the perioplic corium
What is the coronet?
junction of haired skin and hoof wall.
What makes up the bulk of the hoof wall?
stratum medium
Stratum medium produced by?
GE of epidermis at the coronary corium location
Inner part of stratum medium is
non-pigmented
coronary corium papillae project into holes in the ___________ of the hoof wall and nourish the GE that produces __________; intertubular horn fills in between tubules.
coronary groove
tubular horn
Stratum internum comprised of?
deepest layer; rows of parallel, vertically oriented, non-pigmented epidermal lamina
Stratum internum produced by?
produced by GE of epidermis at coronary corium location, NOT by the GE of epidermis covering the laminar corium.
Stratum internum interdigitate with the
sensitive dermal laminae (laminar corium)
What is fused to the surface of Pd?
laminar corium
What is the critical structure linking epidermis to dermis?
basement membrane
The horse is suspended in its hoof by?
basement membrane
Growth of hoof wall direction?
towards the ground
How does the epidermis moves past the dermis as the hoof grows?
constant remodeling at the junction
How are gaps (once occupied by dermal laminae) filled in between the continuing epidermal laminae?
GE covering terminal papillae at the distal end of the dermal laminae produce horn to fill the gaps between the epidermal laminae.
What is the white zone?
non-pigmented inner stratum medium + non-pigmented stratum internum (epidermal laminae) + pigmented horn produced by terminal papillae.
What is the White line? Clinical relevance?
non-pigmented inner stratum medium
clinically relevant landmark on ground surface of hoof wall, used by farriers to set hoof nail position so as to avoid nail penetration of sensitive dermal tissues.
Sole is softer epidermis than?
Wall
Sole produced by?
Produced by the GE covering the sole corium.
Softest epidermis?
frog
Frog produced by?
GE covering the frog corium
Frog function?
weight bearing function – shock absorption and foot pump.
Medial and lateral collateral cartilages of the foot extend from the
palmar processes of Pd
What is sidebone?
ossification of the cartilages; age-related change or related to foot imbalance.
How much does the hoof wall grow per month?
8 mm
How long does it take for the hoof wall to grow out?
9-12 months
Growth of hoof wall affected by?
genetics, environment, and nutrition
What do growth rings reflect?
stressors on normal foot physiology
Average timeline of hoof trimming?
4-8 weeks
What is laminitis? Structural failure of the _________________ bond occurs.
inflammation of the sensitive laminae (laminar corium) of the foot.
hoof wall–laminar corium bond
As disease progresses, Pd separates from hoof wall and _______ palmarly due to pull of DDFT.
rotates
Clinical signs of laminitis?
reluctance to walk; elevated HR, RR; characteristic stance; throbbing digital pulses.
If severe failure of bond, entire bony column of limb will ____ directly towards the ground.
sink
Heel blub and digital cushion of artidactyl hooves form? Function?
digital pad
provides weight bearing support
For cattle the which PL claw bears the most weight? TL?
Outer and inner
What do you have to cut through to perform a digit amputation?
distal interdigital ligament
Importance of the equine foot pump?
At stride impact, the structures listed above change shape (expand or compress) and compress on the venous plexuses, forcing blood out of the foot proximally into digital vv.
This expansion and compression absorbs shock and pumps venous blood back out of the foot.
Where do farriers not place nails and why?
Because heels naturally expand (spread out) on foot fall, shoe nails are not placed in the heel region of the foot.
