Lecture 7: Hoof anatomy Flashcards
Protective layer to prevent desiccation
Analogous to a cuticle
Periople
Primary weight-bearing structure
wall
what does the wall provide? what is it made of
Protection, force dissipation, traction
Keratinized, tubular epidermis
Extension of wall is known as
bars
purpose of the bars on the hoof of a horse
Provides additional weight bearing surface
Prevents excessive expansion → buttress
purpose of the heel
Shock absorption → Distributes of forces
**commonly diseased
Junction between solar and laminar epidermis
Area where nails are driven in on a shod horse
white line
white line (not actually white)
(bacteria can get in here and cause white line disease)
the wall is what shaped structure
tubular (a bunch of little tubes/straws together)
Protects bottom of P3
Bears less weight compared to wall (bottom of hoof is concave) and provides traction
sole
Lies over the digital cushion → Peripheral pump; provides traction
Frog
identify the parts indicated by the 3 colors
Hoof wall (coronary epidermis) overlying coronary dermis
Coronary band
Coronary band
Junction between hoof wall (coronary epidermis) and skin (epidermis)
Coronet
what happens if the coronary band is injured
impacts how the nail will grow; therefore can lead to how sound the horse is
T/F Hoof epidermis is keratinized
true
Corium is another word for
dermis
what are the dermal layers of the hoof
Coronary dermis
Laminar dermis
what does the Laminar dermis supply
Supplies laminar epidermis
what does the Coronary dermis supply
Supplies keratinized coronary epidermis that
forms tubule and intertubule horn
what are the epidermal layers of the hoof
Coronary band
Coronary groove (sulcus)
Coronary epidermis (Stratum medium)
Laminar epidermis (Stratum internum)
Hoof Growth: _____ per month
6-9 mm (may slow to about 3mm in the winter)
is the CORONARY EPIDERMIS or CORONARY DERMIS keratinized
List the 3 step process of hoof wall growth
- Keratinized coronary epidermis
formed by basal epidermal cells at
coronary band **TUBULAR - Continuous with keratinized laminar
epidermis - Desmosomes detach between
epidermal and dermal lamina to let
coronary and laminar epidermis
“ratchet” or move down
___________ detach between epidermal and dermal lamina to let coronary and laminar epidermis “ratchet” or move down
Desmosomes
SOLE GROWTH:
Horn tubules orientated _______
Growth limited by _________ at ground
vertically; curling of tubules
T/F The horse walks directly on its third phalanx
FLASE; P3 is suspended in hoof capsule by the lamina
what is the suspensory appartus of P# and what interdigitates
Laminar dermis interdigitates & supplies laminar epidermis
WHAT HAPPENS IF THE SUSPENSORY APPARATUS FAILS?
P3 rotates, laminitis because bone is no longer supported
WHAT HAPPENS IF THE SUSPENSORY APPARATUS FAILS (AFTER rotation occurs)
sinking, which means the horse is basically walking directly on P3
if P3 has sunk, can’t treat
(pink shows where it should be)
what does this show
sinking due to failure of the suspensory apparatus
WHY DOES THE SUSPENSORY APPARATUS OF P3 FAIL?
Still under investigation
* Insulin dysregulation
* Endothelial cell and vascular dysfunction
what are some conditions mentioned with regards to P3 suspensory apparatus failure
- Metabolic syndrome and insulin resistance
- Pars Pituitary Intermedia Dysfunction (PPID or Cushing’s)
- Endotoxemia (Colic,Retained placenta, Colitis)
- Physical demand
BLOOD & NERVE SUPPLY TO THE HOOF
Medial/Lateral Palmar/Plantar Digital
* Vein, Artery, Nerve
Medial/Lateral Palmar/Plantar Digital vessels enter on palmar and plantar aspect of P3
how does the artery enter vs. vein exit
- Arteries though foramen in P3
- Venous drainage primarily along dorsal border of P3
T/F there is extensive branching of blood supply to the hoof
true Extensive branching
* Venous plexuses
what venous plex is this:
In sole corium, around toe, between sole and digital cushion
Palmar venous plexus
what venous plex is this:
In laminar corium
Dorsal venous plexus
what venous plex is this:
At coronet – in coronary and perioplic corium
Coronary venous plexus
purpose of venous plex
Drains into digital veins; very unique
“hoof pump”
what is this showing?
what vessel??
NEED TO CHECK
Venography- way to assess disease
vessel= palmar/plantar digital
Normal or abnormal venogram
abnormal; absent of contrast tells us which side is compromised
Collateral cartilages attach to ___ and provide structural support for
P3, heel bulbs
purpose of Collateral cartilages
- Shock absorption- Dissipates force through
their expansion - Involved in blood pumping
action of foot
what is in teal? purple?
NAME ALL OF THESE STRUCTURES?
which nail would cause probably most trouble
becuase of the navicular bursa
(leave nail in while you XRay to see what it hit)
synovial structures of the foot:
since they are all connected what does this mean
infection can spread easily
Hoof function (5 main)
- Traction
- Shock absorption
- Support of skeletal column
- Protection of inner structures
- Venous return (peripheral pump)
list the structures of the hoof involved in:
traction
- Frog, shape of hoof (concave), wall
list the structures of the hoof involved in:
shock absorption
- Digital cushion, ability to expand at heels
list the structures of the hoof involved in:
support of skeletal column
- Weight of horse transmitted via lamina to hoof wall
- Suspends P3
list the structures of the hoof involved in:
protection of inner structures
- Periople protects from evaporation
- Hoof wall protects lamina
list the structures of the hoof involved in:
venous return
Frog, digital cushion, collateral cartilages
Synovial fossa
Superimposed on medullary cavity
Flexor tendon runs at flexor surface
idnetify ligament
Synovial fossa
Superimposed on distal border
list in order from top to bottom
first arrow: p2
second arrow: navicular bone
identify ligaments
navicular bone
what happens when there is navicular disease
navicular bone remodels and medullary cavity fills
identify the borders of the navicular bone
***navicular bone articulates with P2 and 3
name the bone
navicular bone
what makes up the navicular apparatus
what bone is this
navicular bone
anatomical name for navicular bone ?
what is its function?
distal sesamoidean bone
Acts as pulley:
* ↓ strain on DDFT as it changes direction to cross coffin joint
* ↓ work of DDFT to act on P3 (↑ its mechanical effect)
what phase is this
Stance Phase
(diastolic)
what phase is this
Flight Phase
(systolic)
Hoof as a pump:
Muscle normally required to achieve effective _______ in periphery
venous drainage
T/F No muscle in digit
true
Digital cushion functions as “pump”
explain
- When horse bears weight digital cushion expands and veins compressed → blood pools in venous plexus and digital cushion
=Diastolic phase - When horse lifts hoof digital cushion contracts and veins open → blood forced out
=Systolic phase
