Lecture 16 3/8/24

Question 1

What are the functions of the passive stay apparatus?

Answer 1

-energy conservation
-relax/nap without laying down
-allows for quick return to sprint

Question 2

What are the osseous components of the thoracic limb involved in passive stay?

Answer 2

-scapula
-humerus
-radius/ulna
-carpals
-metacarpal
-phalanges

Question 3

Which aspects of the humerus are important for passive stay?

Answer 3

-intertubercular groove
-intermediate tubercle

Question 4

Which adaptations of the carpals help to prevent extension?

Answer 4

-column nature
-front of carpus is squared off
-back side is rounded for flexion

Question 5

Which ligament aids the carpals?

Answer 5

palmar carpal lig.

Question 6

What are the characteristics of the biceps brachii tendon of origin?

Answer 6

-partially locks humeral joint
-grips intermediate tubercle

Question 7

What are the characteristics of the biceps brachii tendon of insertion?

Answer 7

-anchors muscle to proximal radius
-tendinous connection with lacertus fibrosus to extensor carpi radialis m.

Question 8

Which bone does the extensor carpi radialis m. anchor to?

Answer 8

MC 3

Question 9

What are the characteristics of the interosseous m.?

Answer 9

-entirely tendinous
-non-stretchable
-contributes to passive stay apparatus

Question 10

What are the characteristics of the SDF and DDF?

Answer 10

-contain muscle fibers/will stretch
-have proximal and distal check lig.
-part of passive stay bc of check ligaments
-applied weight pulls against these structures to fix into place

Question 11

What are the characteristics of the proximal and distal check ligaments?

Answer 11

-tendinous
-prevent joint hyperextension

Question 12

What is the function of the extensor branches of the interosseous m.?

Answer 12

prevent knuckling

Question 13

What are the characteristics of the pelvic limb reciprocal apparatus?

Answer 13

-involves peroneous tertius, which is entirely tendinous
-also involves SDF, which is mostly tendinous
-both muscles act on the stifle joint and hock

Question 14

Which components contribute to the patellar locking mechanism?

Answer 14

-medial patellar ligament
-patella
-medial aspect of patellar fibrocartilage
-ridge of medial trochlea

Question 15

What are the steps of the patellar locking mechanism?

Answer 15

-extension of stifle joint
-patella moves over ridge
-fibrocartilage catches and shifts medial patellar lig.
-rest without flexion of joints due to reciprocal app.
-exit lock via flexion of quadriceps femoris m. and extension of stifle joint

Question 16

What are the characteristics of the coxal joint?

Answer 16

-no contribution to passive stay
-must engage hip muscles to remain standing
-results in horse alternating pelvic limbs when fatigued

Question 17

What are the characteristics of persistently locked patella?

Answer 17

-can be due to trauma, fatigue, muscle atrophy
-can cut medial patellar lig. to treat

Question 18

What are the characteristics of reciprocal apparatus failure?

Answer 18

-can be identified during lameness exam
-both joints are no longer “connected”
-peroneous tertius ruptures are most common cause