THRA.24 Flashcards
The architecture of the trunk is referred to as…
‘Bow and string’ theory
Bow: thoracolumbar vertebrae
String: abdominal muscles
Design of the body is to allow…
Low energy expenditure
The joints of the animal should be stabilised to…
- Prevent unwanted abduction/adduction
- Coordinate flexion/extension
Maximising efficient transmission of thrust
M. serratus ventralis is adapted to…
- Carry considerable weight with minimum effort
- Due to high tendinous tissue
The function of collateral ligaments
- Limit range of flexion and extension
- Exception: Shoulder joint
The function of collateral ligaments in the shoulder
- Present a force which must be overcome to move
- Prevents flexion of the elbow due to body weight
Stay apparatus
- Tendinous-ligamentous support system in equine
- Allows the horse to stand for long periods
Give the mechanism of the stay apparatus
Whilst standing
- Contraction of the supraspinate and triceps muscles
- Tension of superficial + deep digital flexor muscles
Results in passive tension → Maintains elbow extension
Why is weight-bearing on the carpus effortless?
Axis of the radius + cannon bone are in the same vertical line
The carpus is prevented from buckling forward by the…
Lacertus fibrosus
Overextension of the carpus is prevented by…
- Caudal ligaments
- Ligaments of the accessory bone
- Check ligaments
What provides the main support of the fetlock?
Suspensory ligament
(Palmar + planter)
Suspensory ligament prevents…
Overextension of the fetlock during locomotion
During locomotion, the suspensory ligament is supported by…
SDF + DDF
Suspensory ligament
Lacertus fibrosus
Effect of body weight on the fetlock joint
Extends the fetlock
Which structures prevent muscular effort in the equine hindlimb?
- Collagenous bands derived from muscular tissue
- Skeletal adaptations
What does this figure represent?
The patellar lock/loop
Middle patella ligament
Superficial digital flexor tendon
Third fibular muscle
Accessory ligament
Suspensory ligament
Patellar loop causes
- Locking of patella
- Immobilisation of the stifle
- Immobilisation of the hock
Initiation of the patella loop
- Extension of stifle beyond the proximal trochlear groove
- Medial twist of the patella
- Parapatellar cartilage is hooked over the trochlear tubercle
Function of patella loop
- Allows the horse to rest its weight on one hindlimb
- With minimum effort
How is the patella loop stopped?
- Weight is shifted to the other limb
- Quadriceps draws the patella proximally
If the patella loop cannot be unlocked, what can be observed?
The horse drags the toe
Reciprocal apparatus
- Flexion of the stifle
- Flexion of the hock
Muscles involved in the reciprocal apparatus
- Gastrocnemius
- Third peroneal muscle
- SDF
Give the natural gaits
- Equine:
- Walk
- Trot
- Gallop
- Other animals:
- Pace
- Amble
- Rack
Walk
- 4-beat gait
- 2 feet always in contact with the floor
- Left hind
- Left fore
- Right hind
- Right fore
Trot
- 2-beat gait
- Opposite fore + hind feet hit the ground together
- Right fore + left hind
- Left fore + right hind
Gallop
- 4-beat gait
- Either left or right forelimb leads
- Right fore
- Left hind
- Right hind
- Left fore
Walking
Trotting
Gallop
What is a stride sequence?
Movement of a limb with:
- Swing phase
- Stance phase
