Distal limb Flashcards
What region is considered distal limb?
Distal to carpus/tarsus joint all the way to the end of the distal phalanges
How is the distal limb different in animals adapted for speed?
Limb elongation and reduced mass
What are the 3 synovial structures used ft intra-articular injection?
- MCP joint
- PIP joint
- DIP joint
Where are the extensor tendons of the forelimb located?
What does damage to them result in?
Which is the main extensor?
Dorso-lateral aspect
Dropping of elbow and knuckling
Common digital extensor
Where are the extensor tendons of the hindlimb located?
Which is the main extensor?
Dorso-lateral aspect
Long digital extensor
How is weight distributed in the legs?
Muscles at top as the are heaviest and then tendons running down for support of the lower limb
How many and which nerves innovate the forelimb extensors and flexors?
Extensors = 1, radial
Flexors = 2, median and ulnar
How many and which nerves innovate the hindlimb extensors and flexors?
Extensors of hock, flexors of digits = 1, fibula
Flexors of hock, extensors of digits = 1, tubular
Where are the flexor tendons located?
What are the two main for both fore and hind?
Palmer/plantar aspect of both fore and hind
Superficial digital flexor tendon
Deep digital flexor tendon
SDFT
Where is it located?
How does it travel down the leg?
What is the name of the sleeve it form around the DDFT?
What is it’s function?
Subcutaneous and palpable
Distal end of P1 splits and insets on P2
Manica flexoria
Flexes whole digit and stabilises fetlock
DDFT
Where is it located?
How does it travel down the leg?
Deep to SDFT
Passes through the maniac flexor and inset onto the flexor tuberosity of each functional distal phalanx
What are the main distal limb support structures?
What is different about them in horses?
Third/middle interosseous muscle/Suspensory ligament
- sesamoid ligament
AND
Accessory check ligament
(TIOM) Completely tendinous
What part of the distal limb is part of the suspensory apparatus?
third interosseous muscle/suspensory ligament, prevents excessive extension of the fetlock
What path does the third interosseous muscle/suspensory ligament follow down the distal limb?
Where is it located?
Origin = proximal metacarpal between splint bones
Inserts = divides above fetlock to insert on surface of proximal sesamoids
Then, continues past the sesamoid as the seamoidean ligaments to the phalanges
(extensor branches run to the extensor tendon)
Deep to the SDFT and the DDFT
What is the other name for the accessory ligaments?
Where are they located?
What are their functions?
What is the difference between them in the fore and hind limb?
Check ligaments
Accessory of the SDFT - connects the SDFT to the radius just above the carpus
Accessory of the DDFT - connects the DDFT to the carpal region
Limit movement of the tendon to prevent ver stressing and to support the MCP joint through the anchoring of those flexor tendons
Weak/absent in hind
2 (proximal and deep) prominent in fore
Name the 4 protection mechanisms in the distal limb and explain what they are:
- Bursae - Cushing tendons in areas at risk of damage, distributing the pressure (example = navicular bursae)
- Digital flexor tendon sheath - encompasses flexor tendons in both fore and hindlimb extending from the fetlock joint to the middle of P2
- Annular ligament - local thickening of facia to stabilise the tendons
- Dorsal elastic ligament - allows retraction of the vital phalanx pulling it lateral to the middle (dogs and cats)
What nerves supply sensory innervation to the forelimb?
What are the 2 nerve blocks that can be done in the equine distal forelimb?
- Palmar digital nerve block
- pastern region
- neuromuscular bundle palpated next to abaxial flexor tendon
- desensitises hoor structure (not dorsal coronary band - Abaxial sesamoid nerve block
- Palmer digital nerves on abaxial surface of proximal sesamoid bones
- neuromuscular bundle palatable over sesamoids
- desensitises digit and caudal fetlock joint
What does VAN help you remember when doing a nerve block?
VeinArteryNerve
so nerve is most palmar/closest to surface so pull needle back to ensure not in vein or artery
What nerves supply sensation innervation to the distal hindlimb?
Fibular = dorsal
Tibial = palmar
Which nerves are blocked in the forelimb?
Which nerves are blocked in the hindlimb?
Radial nerve terminates at carpus, so dorsal supply comes from medial and ulnar nerves – can be blocked on palmar aspect
Fibular nerve supplies dorsal aspect and must be blocked on here
