Hindlimb comparative Anatomy

Question 1

What is the horse stay apparatus

Answer 1

Ability to lock weight bearing hind limb in extension

Question 2

Mechanism of stay apparatus in hindlimb

Answer 2

1. stifle joint - patella and patellar ligaments. Tuber on medial trochlear ridge, locks patella
2. Hock - recriprocal apparatus
3. Digits - suspensory apparatus of the fetlock

Question 3

The stay apparatus - which muscle suspends the weight of the body between forelimbs?

Answer 3

Serratus ventralis

All weight down to distal strucutre

Question 4

Ratio of weight bearing fore to hindlimb stay apparatus

why?

Answer 4

60% fore
40% hind
More pressure on forelimb from head and neck!

Question 5

What structures contribute to passive mechanism of stay apparatus horse proximally

Answer 5

1. Serratus ventralis
2. Shoulder - biceps brachii fibrous sheath of connective tissue attached to extensor carpi radialis, inserts to proximal metacarpal bone
3. Elbow - collateral ligs (caudal)
   alignment of bones
4. Carpus: lacertus fibrosis