Reciprocal and Stay Apparatus

Question 1

what is the goal of the stay apparatus?

Answer 1

to prevent flexion of the stifle and tarsal/carpal joints and overextension of the metatarsophalangeal (fetlock) joint when horsey at rest; help horsey stay standing without expending too much energy

Question 2

describe the fetlock joint at rest in the stay apparatus

Answer 2

fixed in extension; supported by the SDFT, DDFT, suspensory apparatus, and distal sesamoidean ligaments

Question 3

do ruminants have a stay apparatus?

Answer 3

nope

Question 4

what is the goal of the reciprocal apparatus?

Answer 4

to link the action of the stifle and tarsal joints

Question 5

describe the reciprocal apparatus (3)

Answer 5

1. patellar ligaments lock to extend the stifle
2. SDF and the fibrous band of the gastrocnemius keep hock extended while stifle extended by the patellar ligaments
3. peroneus tertius flexes hock when stifle is flexed

Question 6

do ruminants have a reciprocal apparatus?

Answer 6

sure do

Question 7

what are the components of the stay apparatus in the forelimb? (9)

Answer 7

1. tendon of serratus ventralis
2. internal tendon of biceps brachii
3. lacertus fibrosus of biceps brachii
4. collateral ligaments of the elbow
5. SDF and proximal check ligament
6. DDF and distal check ligament
7. interosseus suspensory ligament
8. distal sesamoidean ligaments
9. extensor branches of interosseus

Question 8

what are the components of the stay apparatus in the hindlimb?

Answer 8

1. SDF
2. fibrous band in gastrocnemius
3. patellar ligaments
4. peroneus tertius
5. DDF and distal check ligament
6. interosseus
7. distal sesamoidean ligaments
8. extensor branches of interossues
   (1-3 are most important)

Question 9

what are the 2 parts of the reciprocal apparatus?

Answer 9

1. peroneus tertius
2. SDF/gastrocnemius fascial band
   allow for simultaneous flexion and simultaneous extension of stifle and hock