Reciprocal apparatus of horse

1. On cranial aspect is peroneus tertius from between trochlea and lateral condyle..inserting in tarsometatarsal region

1.1. Ensure flexion of stifle accompanied by flexion of hock

2. Patellar locking

2.1. Immobilization of stifle joint

2.1.1. decrease muscle fatigue

2.2. Lateral,medial patellar ligament bind patella to tibia,while medial patellar ligament attach patellar cartilage to tibia

2.3. Patella move to proximal extremity of trochlear groove

2.4. Patella is locked and further extension is not possible

2.5. No muscle activity needed to maintain the leg in this position

2.6. Horse rest lot of its weight on this leg

3. Reciprocal mechanism

3.1. On caudal aspect,superficial digital flexor and fibrous band of gastocnemius

3.1.1. Ensure extension of hock when stifle is in extension

4. Check apparatus

4.1. Accessory ligament of deep digital flexor tendon