DISTAL LIMB Flashcards
Where would you administer the palmar digital nerve block
Pattern region
How can you palpate the position for the palmar digital nerve block
Neurovascular bundle abaxial to the flexor tendons
What does the digital palmar nerve block desensitise
Hoof region except the dorsal coronary band
Where do you insert the palmar digital nerve block
Abaxial surface of the proximal sesamoid bones
What structures do you palpate for the abaxial sedamoid nerve block
Neurovascular bundles over the proximal sesamoid bones
What does the abaxial sesamoid nerve block desensitise?
The digit and caudal fetlock joint
When should you not administer regional anaesthesia
Animals with:
Severe tendon injury
Suspected fracture
Localised infection
What are the 4 synovial joint places in horses
- PIP
- MCP
- DIP
- Common flexor tendon sheath
Where are the extensor tendons of the digits found
Dorso lateral aspect
What innervates the extensor of the digits in forelimb
Radial nerve
What is the main extensor tendon of the digits in forelimb
Common digital extensor
(They do have lateral extensor but not really in horses as they only have one digit)
Where are the extensor tendons found in the hindlimb
Dorsal lateral aspect
What innervates the extensor tendons in the hindlimb?
Fibula nerve
What is the main digital extensor tendon in the hindlimb
Long digital extensor
(There is a lateral digital extensor but horses only have one toe)
Where are the flexor tendons of the digits located
Palmar aspect
Where is the SDFT located?
Subcutaneous and palpable
From hock and at P2 splits into two
What is the function of the SDFT
Stabilises fetlock joint
Flexes whole digit
Where is the DDFT
Runs deep to SDFT
Starts at same place as SDFT but goes down to P3
Inserts on distal phalanx of each functional digit
What is the function of the DDFT
Stabilises fetlock joint
What is the manica flexoria
The DDFT goes more distal than the SDFT so needs to go through it
The SDFT splits into two and DDFT goes through tube it created
What is the difference in the interosseus muscle in different animals
Dogs/ cats —> muscular
Horses —> tendonous
Where does suspensory ligament divide
Just above fetlock joint into branches on each sesamoid bone
Which limb is accessory (check) ligament more prominent
Forelimb
What is the function of the accessory (check) ligaments
Ligament of SDFT connects tendon to radius
Ligament of DDFT connects tendon to carpal region
What are annular ligaments
Thickenings on fascia
Stabilises tendons
What allows cats to retract the claws
Dorsal elastic ligament
What nerves supply to the extensors of the digits
Radial nerve
What nerves supply to the flexors of the digits
Ulnar
Median
How does the palmar digital nerve block work
Desensitises hoof structures other than coronary band
Palpate Neurovascular bundles abaxial to flexor tendons
How does the abaxial sesamoid nerve block work?
Palpate Neurovascular bundles over proximal sesamoid bones
Desensitise digit and caudal aspect of the fetlock joint
How do you block fibula nerve on hindlimb
Block dorsal and plantar aspect
How do you block dorsal supply in forelimb
Can be blocked on palmar aspect
What is important about the vasculature of digits in ruminants
Dorsal supply
Dorsal common digital vein can be used for IV access
Stump of axial palmar artery bleeds on amputation of digit so ,just be ligated
In ruminants which claw takes more weight
Lateral claw
In front feet which claw in ruminants is bigger
Media;
In ruminants himd feet which claw is bigger
Lateral clawwhat
What is the white line
Unpigmented joim between inner hoof wall and sole
What is the periodic epidermis
Thin membrane that grows from outer edge of coronary band down the hoof wall
Produces a thin waxy waterproof cover
What are the two layers of claw horn
Living dermis
Epidemis
What is the dermis like on hoof of ruminants
Living tissue
Blood vessel s
Nerve supply
What is the epidermis of hoof like on ruminants
Inner part has living cells producing horn
Outer part is dead horn
How quickly does the wall horn grow
5mm a month
What length should the foot horn be in ruminants
90mm
How is horn formed
Keratinsatiom (differentiation of living epidermal cells)
Cornficiagiom (programmed cell death of living epidermal cells)
This final product makes home
What is different between between hoof in pigs and cows
In pigs, wall is straight not bent mediallynat toe
In pigs soft bulb is well distanced from the wall and sole
How does the suspensory apparatus work in cows
Collagen fibre bundle holds and supports P3 within hoof capsule
Underneath P3 is an interdigital fat pad cushion
Where does the suspensory ligament divide into two branches
Just proximal to fetlock joint
What tissue makes up the footpads
Subcutis
Adipose tissue
Collagen
Elastic tissue
What is the function of the foot pads
Supports animals weight
Distributed weight
Friction
What structure enables cats to retract their claws
Dorsal elastic ligaments
What veins/ arteries are there in the distal limb
Lateral and medial digital vein/ artery
Medial palmer artery/ vein (and nerve)
What is special about the veins in the equine distal limb
No valves In plexuses (congregation of veins)
Horses need to move to drain blood back up towards heart
How does the epidermis and dermis fit onto one another in hoof
Via lamallea
Why does laminitis occur?
Failure of adhesion of cells to basement membrane
Detachment and deformation of dermal/ epidermal junction
How does the hoof grow
In coronary band Dermal papillae (tentacles/ out pouches of dermis) creates tubes of squamae
The tubes fit over the papillae
Intertubular horn is made by cells in the base of the papillae
What are so,e complications that can arise at the white line
Sub solar absess
Seedy toe
White line disease
What is the stratum internum
The layer with the epidermal lamallae
What is the stratum medium
Bulk of the hoof wall
Layer with horn tubules and intertubular horn
What is the stratum externum
Thin, waxy layer of keratin
What are the adaptations to help P3 weight load
Suspended from, hoof wall
Collagen fibre bundles run between P3 and inner aspect of claw capsule
