Lecture 15- Posture and Passive-Stay Apparatus

Question 1

Tarsus in layman’s terms

Answer 1

Hock

Question 2

Carpus in layman’s terms

Answer 2

Knee

Question 3

Second metacarpal in laymen’s terms

Answer 3

Splint bone

Question 4

Third metacarpal in layman’s terms

Answer 4

Cannon bone

Question 5

4th metacarpal in layman’s terms

Answer 5

Splint bone

Question 6

Metacarpophalangeal joint in laymen’s terms

Answer 6

Fetlick

Question 7

phalanx 1 in laymen’s terms

Answer 7

Long pastern

Question 8

Phalanx 2 in laymen’s terms

Answer 8

Short pastern

Question 9

Phalanx 3 in laymen’s terms

Answer 9

Coffin bone

Question 10

When standing it is optimal to place axis of each joint where?

Answer 10

Directly under th line of gravity of the limb

Question 11

What are the two problems with horses standing for long periods of time

Answer 11

1: exact positioning of muscles is possible so without support force due to gravity joints would collapse
2: muscles are energetically costly

Question 12

What is the solution to preventing joint collapse and not using lots of muscular energy

Answer 12

Passive stay apparatus

Question 13

What is the passive stay apparatus

Answer 13

Combines force of gravity with properties of skeleton, tendons, and ligaments to maintain balance during standing while reducing muscular effort to a minimal level

Question 14

What are the three components of passive stay apparatus

Answer 14

Suspensory, check, and stay

Question 15

What is the suspensory apparatus composed of

Answer 15

Interosseous ligaments and distal sesamoid

Question 16

What is the interosseous ligament, where does it arise, insert

Answer 16

Part of suspensory ligament. Arises from palmar carpal ligament and MCIII and travels between Splint bones and splits to insert on abaxial side of proximal sesamoid

Proceeds along dorsal surface of 1st phalanx and attaches to extensor digitorum

Question 17

What extends the suspensory apparatus to the pastern

Answer 17

Distal sesamoidean ligaments

Question 18

The suspensory apparatus prevents ____ of the manus and pes

Answer 18

Hyperextension of MCP, pastern, and coffin

Question 19

What will happen if you pull on suspensory apparatus

Answer 19

Coffin joint will flex and move palmar surface into caudal position

Extensor branch of interosseous passes dorsally from suspensory lgiament to join extensor diagtorum communis. Coffin bone is extended back into proper position without extension of fetlock and pastern

Question 20

What is the check apparatus composed of

Answer 20

Flexor digitorum profundus (fore and hindlimb)

Flexor digitorum superficialis

Question 21

Check ligament in flexor digitorum superficialis

Answer 21

Accessory/superior/proximal ligament is tendenous radial head of superficial digital flexor that joins muscle tendon distal to carpus

Forms ligamentous connection from radius to pastern joint

Question 22

What does the accessory/superior/proximal ligament prevent

Answer 22

Hyperextension of carpal and fetlock joints

Question 23

What is check ligament in flexor digitorum profundus

Answer 23

Accessory/inferior/distal check ligament arises from carpal joint and inserts on FDP

Forms ligamentous connection all the way to coffin joint

Question 24

What does the accessory/inferior/distal check ligament prevent

Answer 24

Hypertension of fetlock, pastern, and coffin joints

Question 25

What muscles are involved in stay apparatus of thoracic limb

Answer 25

Serratus ventralis, biceps brachii, lacertus fibrosus, extensor carpi radialis

Question 26

What muscles are involved in reciprocal mechanism of pelvic limb

Answer 26

Perioneus teritus and flexor digitorum superficialis and fibrous band of gastrocnemius

Question 27

What supports the cranial part of body and connects costal side of scapula to caudal cervical vertebrae and cranial ribs

Answer 27

Serratus ventralis

Question 28

Stay apparatus

Answer 28

Flexion of GH pulls on internal biceps brachi tendon cranially Bicep tendon connects to leg via lacertus fibrosus and extensor carpi radialis. As leg is fixed this causes tendon of biceps to pull distally and pull scapula back into place Weight of body will cause carpal joints to collapse into Flexion if left uncheck so force through lacertus fibrosus and extensor carpi radialis prevents carpal joints from going into flexion

Question 29

Reciprocal mechanism

Answer 29

Ensures that when femur swings one way distal limb will swing opposite way. Ensures that when patella is locked the hock is also immobile Allows joints to move in unison

Question 30

What causes flexion of stifle to produce flexion of hock

Answer 30

Opposing fibrous connections of flexor digitorum superficialis and perooenus tertius

Question 31

Rupture of peroneus tertius

Answer 31

Decoupling of reciprocal mechanism, flexion of stifle will not force flexion of hock

Question 32

What causes locked patella

Answer 32

Medial patellar ligament remains hooked over medial epicondyle ridge Temporary can startle or exercise out Permanent- startling does not release stifle