CHP 6 - STAY APPRATUS IN HORSES

Question 1

A mechanism in horses that allows them to stand for long periods with minimal muscular effort

Answer 1

Stay apparatus

Question 2

Prevents flexion in the stifle and hock joints and overextension in the fetlock and phalangeal joints

Answer 2

Passive stay apparatus

Question 3

Forms bony columns that would collapse without the support of intrinsic limb muscles

Answer 3

Forelimb angulation

Question 4

Become fatigued without the support of tendons and ligaments in the stay apparatus

Answer 4

Intrinsic limb muscles

Question 5

The primary weight-bearing muscle in the forelimb with tendinous tissue reducing effort

Answer 5

Serratus ventralis

Question 6

Achieved by the biceps tendon pressing against the cranial surface of the joint

Answer 6

Shoulder stabilization

Question 7

Caps the intermediate tubercle of the intertubercular groove to help lock the joint

Answer 7

Biceps tendon

Question 8

Connects the biceps tendon to the extensor carpi radialis aiding in stability

Answer 8

Lacertus fibrosus

Question 9

Maintained by carpal and digital flexors that originate from the humerus

Answer 9

Elbow stabilization

Question 10

Structures that assist in elbow stability but play a minor role in preventing flexion

Answer 10

Collateral ligaments

Question 11

Appears inactive when the horse is standing but may contribute to joint stabilization

Answer 11

Triceps brachii

Question 12

Maintained by extensor carpi radialis and supported by accessory ligaments

Answer 12

Carpal joint stabilization

Question 13

Contributes to stability by pulling on the flexor surface of the carpal joint

Answer 13

Flexor carpi ulnaris

Question 14

Works with flexor carpi ulnaris to stabilize the carpus under body weight

Answer 14

Ulnaris lateralis

Question 15

Structures that attach to the palmar surface of the radius and metacarpal bone for additional support

Answer 15

Accessory ligaments

Question 16

Prevents overextension through the suspensory apparatus and digital flexor tendons

Answer 16

Fetlock stabilization

Question 17

A system consisting of the interosseous muscle proximal sesamoid bones and sesamoidean ligaments

Answer 17

Suspensory apparatus

Question 18

Originates from the carpus and metacarpus and inserts on the proximal sesamoid bones

Answer 18

Interosseous muscle

Question 19

Reduce friction and provide a bearing surface for digital flexor tendons

Answer 19

Proximal sesamoid bones

Question 20

Include short cruciate oblique and straight ligaments extending support past the fetlock

Answer 20

Sesamoidean ligaments

Question 21

Assists in stabilizing the fetlock by spanning from the radius to the phalanges

Answer 21

Superficial digital flexor tendon

Question 22

Provides additional support and inserts on the distal phalanx

Answer 22

Deep digital flexor tendon

Question 23

Prevented from overextension by pastern ligaments and the suspensory apparatus

Answer 23

Pastern stabilization

Question 24

Supported by the navicular bone and ligaments but not critical to the stay apparatus

Answer 24

Coffin joint stabilization

Question 25

Provides a bearing surface for the deep flexor tendon and reduces friction

Answer 25

Navicular bone

Question 26

Supports the horse while standing on one hindlimb while the other rests

Answer 26

Hindlimb stay apparatus

Question 27

Links the movement of the stifle and hock ensuring simultaneous motion

Answer 27

Reciprocal mechanism

Question 28

A tendinous muscle that connects the femur to the metatarsal bone for coordinated movement

Answer 28

Peroneus tertius

Question 29

Connects the femur to the calcanean tuber aiding in reciprocal movement

Answer 29

Superficial digital flexor

Question 30

Include short cruciate oblique and straight ligaments extending support past the fetlock

Answer 30

Sesamoidean ligaments

Question 31

Achieved through the interosseous muscle and digital flexor tendons

Answer 31

Fetlock and phalangeal joint stabilization

Question 32

The hindlimb has a thinner or absent check ligament compared to the forelimb

Answer 32

Accessory ligament differences

Question 33

Compensates for the lack of a check ligament in the hindlimb

Answer 33

Calcanean tuber attachment

Question 34

A system that locks the stifle joint converting the hindlimb into a rigid support

Answer 34

Patellar locking mechanism

Question 35

Features a large medial ridge that interacts with the patella for locking

Answer 35

Femoral trochlea

Question 36

Medial and intermediate ligaments that form a loop securing the patella in place

Answer 36

Patellar ligaments

Question 37

A medial shift of about 15 degrees that fully engages the locking mechanism

Answer 37

Patellar rotation

Question 38

A behavior where the horse shifts weight to the opposite hindlimb after a period of standing

Answer 38

Weight shifting