Suspensory Stay and Reciprocal Apparatus, Hindleg locking mechanism Flashcards
What is the function of the suspensory apparatus?
Support the fetlock joint during the weight-bearing phase of the stride
Main contributing causes for suspensory apparatus injuries:
Uneven loading of the limb during weight bearing (lunge lining),
Uneven ground
Poor foot balance
Rider balance
It takes a _____ time to heal suspensory.
Long
The structures that make up the suspensory apparatus include:
Suspensory ligament 2 proximal sesamoid bones Intersesamoidean ligament Distal sesamoidean ligament Collateral sesamoidean ligament Superficial digital flexor tendon Deep digital flexor tendon
The stay apparatus enables the horse to _____ with _____.
Stand for long periods of time with minimal fatigue
The stay apparatus consists of _____, _____, and _____ that _____ and _____.
Muscles, ligaments and tendons that stabilize all the joints of the forelimb and the lower joints (fetlock and pastern) of the hind limb.
_____ is needed to hold tension on these ligaments and tendons, which in turn prevent _____ and _____.
Minimal muscular activity needed; Prevent flexion of the joints and collapsing of the leg
The suspensory apparatus supports the _____ and prevents it from…
Supports the fetlock to prevent it from collapsing and falling to the ground
Of the stifle joint: The end of the femur consists of 2 _____ that roll their way back and forth across the articular surface of the _____.
2 condyles; tibia
Of the stifle joint: There is the _____, which consists of 2 ridges that serves as a _____ system and provides a track for the _____.
There is the trochlea, serves as a pulley system, provudes a track for the patella
Condyles of the stifle joint are _____, while the articular surface of the tibia is _____ and _____.
Condyles - round
Tibia surface is flat and horizontal
The articular surfaces of the tibia in the stifle joint do not correspond, so there are 2 _____ inserted between the two bones. The intercondylar eminence separates the two.
Menisci (mandarin shaped cushions)
The patella rests in the groove of the _____ and is located underneath the end of the _____. It slides between the _____’s ridges in response to the muscle’s movement.
The patella rests in the groove of the trochlea. Located underneath the end of the Quadriceps femoris muscle. Slides between the trochlea’s ridges
When the horse is moving and the _____ is operational, the patella enables the passage of the muscle over ridges of the trochlea.
Quadriceps femoris muscle
When the horse is resting, the patella is a _____ device.
Labor-saving
By raising one hip, the horse can cause the _____ muscle to lift the patella into position above the _____. This _____ the hinge and _____ the limb so that it can become _____. When one hindlimb is fixed, the other can rest on its toe
Cause the quadriceps muscle to life the patella into position above the medial trochleal ridge
This locks the hinge and fixes the limb so that it can become self-supporting.
The hind leg locking mechanism is unlocked by the _____ and _____.
Contraction of the quadriceps femoris muscle and biceps femoris
What can occur if the hind leg locking mechanism doesn’t work properly?
Disease: Upward fixation of the patella
Upward fixation of the patella is seen mostly in _____.
Young, immature horses ad ponies (Shetlands especially)
What are the causes of Upward fixation of the patella?
Straight hindlimb conformation Poor muscle tone Poor condition Hereditary factors Trauma to the stifle
One treatment for Upward fixation of the patella is to establish a _____ to increase level of _____ and _____ of muscle tone.
Establish a “conditioning program” to increase level of fitness and strength of muscle tone
Exercise tediously
One treatment for Upward fixation of the patella is _____. (Hint: Results are unpredictable)
Injecting irritants (“blistering”) into and around middle patellar ligaments to thicken and shorten them.
One treatment for Upward fixation of the patella is _____ with raised heels to help by limiting the degree of _____ of the stifle joint.
Corrective shoeing
Limiting the degree of extension of the stifle joint
Surgical treatments for Upward fixation of the patella:
Med. Pat. Lig. desmotomy (cutting)
Med. Pat. Lig. splitting
One treatment for Upward fixation of the patella is _____ by allowing _____ to increase the strength of the ligament. Administered weekly.
Hormonal therapy
Estrogen
Recpricol apparatus: The _____ cannot move without the _____.
Hock cannot move without the stifle
The _____ (corresponds with the human heel) works as a lever.
Calcaneus
2 fundamental structures of the reciprocal apparatus
1) Peroneus tertius (in front of limb)
2) Superficial digital flexor muscle (behind limb)
The reciprocal apparatus pulls the hock _____
Forward
If the stifle flexes, the _____ closes the angle of the hock and the hock flexes.
Peroneus tertius
The _____ is also connected to the mechanism. It automatically adpots the correct position for whateve the stifle and hock are about to do.
Fetlock joint
The action of the _____ is to extend the stifle joint. In doing this, it automatically engages the _____.
Quadriceps femoris muscle
Engages the reciprocal apparatus
The _____ contracts and extends the hock. This action is limited and influenced by the pelvis’ position.
Gastrocnemius
The _____ gives rise to the Achilles’ tendon, which inserts on the calcaneus tuberosity.
Gastrocnemius
If a horse ruptures it’s peroneus tertius, the leg of the horse…
Can only be held extended
If a horse ruptures the gastrocnemius and superficial digital flexor tendon, the leg of the horse…
Can only be held in a flexed/bended position
