Comparative Hindlimb

Question 1

What is the function of the hindlimb stay apparatus ?

Answer 1

Ability to lock weight bearing limb combined with front stay apparatus to allow horse to sleep whilst standing

Question 2

What are the key components of the HL stay apparatus?

Answer 2

Stifle- patella and patellar ligaments
Hip/stifle/hock- prevention of collapse into flexion
Hock- reciprocal apparatus
Digits- suspensory apparatus of the fetlock

Question 3

How is the patella ‘locked’?

Answer 3

Stifle extends, patella moves proximally and rotates medially, engages horizontal, tubercle of medial trochlear ridge between middle and medial patellar ligaments

Question 4

What makes up the reciprocal apparatus?

Answer 4

Peroneus tertius

Superficial digital flexor- fibrous bands

Question 5

What is the MTP joint?

Answer 5

Metatarsal pharyngeal joint

Question 6

What do the MTP/PIP/DIP do in the stay apparatus?

Answer 6

Prevention of hyperextension

Question 7

What are the different distal sesamoidean ligaments and what joint are they in?

Answer 7

Straight
Oblique
Short 
Cruciate 
Found in the MTP

Question 8

What are the three annular ligaments?

Answer 8

Proximal
Proximal phalanx
Distal

Question 9

What are the 4 bones of the pelvis?

Answer 9

Ilium, ischium, pubis, acetabulum

Question 10

What are the species differences between the wing of the ilium?

Answer 10

Dog and Pig- vertical orientation, flat or convex on cranial margin
Horse and ruminants- horizontal orientation, concave cranial margin

Question 11

What are the differences between tuber ischium between species?

Answer 11

Cow- trifid (3 way projection)

Sheep less distinct but still triffid

Question 12

What is palpable in ruminants?

Answer 12

Tuber sacrale
Tuber coxae
Tuber ischium

Question 13

How does the sacrum vary between species?

Answer 13

Hose, cow and goat- 5 fused sacral vertebrae
Pig/sheep- 4
Dog- 3
Cow- dorsal spinous process of sacrum fuse as ages
Horse- dorsal spinous processes not fused

Question 14

How does the sacrotuberous ligament vary between species?

Answer 14

Dog- fibrous band, S3 to tuber ischium
Cow and horse- fibrous sheet, sacrum to dorsal ilium/ischium, forms lateral wall of pelvic cavity, protects and allows passage of nerves

Question 15

What is the differences between the hip joint between species?

Answer 15

Cow, horse and pig- same features as dog, ligament head of femur
Horse- accessory ligament
Cow- acetabulum has divided articular surface

Question 16

Describe the structure and function of the accessory ligament?

Answer 16

Continuation of the prepubic tendon
runs from pecten under transverse ligament
Tension due to weight of abdominal contents

Question 17

What is different about a cows femur compared to other species?

Answer 17

Medial trochlear ridge larger than lateral- equal in other species
No tubercle
3 patellar ligaments
No patellar locking mechanism

Question 18

How does the tibia and fibula vary between species?

Answer 18

Pig- fibula complete and separate from tibia
Ruminants- remnant of fibula proximally fused distally joined by ligament
Horse-proximal half fused to tibia and distal fused

Question 19

What is the differences in the tarsus between species?

Answer 19

Pig- all 7 bones present
Ruminant- 5 central and 4 fused, 2 and 3 fused
Horse- 6 bones, 1 an 2 fused

Question 20

Why can cows kick laterally?

Answer 20

Rotation possible at proximal intertarsal joint