Hindlimb

Question 1

What allows horses to sleep standing up?

Answer 1

Their stay apparatus - can lock legs without muscular energy

Question 2

What is the passive stay apparatus made of?

Is it in the hindlimb and forelimb?

Answer 2

Tendons, ligaments, muscles with fibrous content

Both hindlimb and forelimb

Question 3

What are the 3 components of the suspensory apparatus in both the fore and hindlimb?

Answer 3

• suspensory ligament
• sesamoid bones
• distal sesamoidian ligaments

Question 4

Which component of the suspensory apparatus resists carpal and fetlock extension?

Answer 4

The distal sesamoidian ligament

Question 5

Where does the suspensory ligament originate and where does it run?

Answer 5

Originates on metacarpal/tarsal 3 and splits into 2 branches attaching to the sesamoid bones and then continuing down further

Question 6

What type of injury is common in the stay and check apparatus?

Answer 6

stay - Suspensory branch desmitis & Sesamoiditis
= repetitive stain injury as when horses run and jump the ligament is stretched. Causes bone damage as well as damage ti the ligaments.

check - check ligament desmitis

Question 7

How do horses remove the weight of their thorax off of their forelimbs?

Answer 7

Through the tendinous layer of the seratus ventralis muscle that suspends the thorax when the muscles relax

Question 8

What is the check apparatus made up of?

What do the ligaments do?

Answer 8

• superior check ligament ie. accessory ligament of SDFT
• inferior check ligament ie. accessory ligament of DDFT

Resist fetlock and carpal hyperextension without muscular effort

Question 9

What does patella locking allow?

How many ligaments are involved?

Answer 9

Prevents tibial flexion
3 patella ligaments

Question 10

How does patella locking work?

Answer 10

Contract quadricep
Patellar fibrocartilage + medial patellar ligament lock over medial trochlear ridge
Stifle locked in extension

Question 11

Is patellar locking an active or passive process?

Answer 11

Active process

Question 12

Why could a patellar stay locked?

Answer 12

Poor muscle condition so quadriceps can not contract well enough to unlock patellar

Question 13

What is the reciprocal apparatus?

Answer 13

When two tendinous cords unite the movement of the stifle and hock
Stifle flexed - Hock forced to flex
Stifle extends - Hock forced to extend
So, when the stifles locked the hock is also locked

Question 14

What are the two tendons involved in the reciprocal apparatus?

Answer 14

1. peroneus tertius - cranial (blue)
2. superficial digital flexor - caudal (red)

Question 15

What are some of the musculoskeletal adaptation horses have for speed?

Answer 15

Increased stride length
- long legs
- scapula can swing
- flattened thorax mediolaterally
- reduced distal mass - 1 digit
- muscle weight proximal
- long tendons
Minimal energy wastage
- limbs move in single plane
- stretched tendons store kinetic energy to release on next stride
- hinge joints

Question 16

What is the calculation for cardiac output?

Answer 16

Cardiac output = stroke volume x heart rate

Question 17

Organise the following into the correct boxes:

Answer 17

Question 18

What are Squamata?

What are testudines/chelonians?

Answer 18

Lizards and snakes

Turtles, tortoises and terrapins

Question 19

What is the quadrate bone in exotic species?

Answer 19

Bone that allows reptiles like snakes to open their mouth fully when eating

Question 20

What is the difference between mammal and exotic vertebrae?

Answer 20

Mammal - built for rigidity, strength and stability
Exotic - built for flexibility (ie. one occipital condyle for extra head movement)

Question 21

Do exotic species have ribs?

Answer 21

Yes, they have true endochondral ribs

May also have gastralia which are ribs caudal to the sternum covering the abdomen

Question 22

How doe bones grow and repair in reptiles?

Answer 22

Growth:
- slow epiphysis, physis nerves close in some specie
- dependant on external factors
Repair:
- very slow, takes months
- less remodelling and periosteal growth

Question 23

What is a lizard anti predator defence mechanism involving their tail?

What is the problem with this?

Answer 23

Caudal tail drop off and continues to thrash when lizard grabbed or startled
The have fracture planes in their tail that allow this

Costly as tail has fat storage (so this is lost) and replaced with cartilage not bone so doesn’t function the same causing problems with locomotion and reproduction

Question 24

What are the vertebrae like in snakes?

Do snakes have sternums?

Answer 24

Precloacal - flexible ribs, flexible
Cloacal + Caudal - no ribs

No as they would reduce flexibility

Question 25

What do snakes rely on for locomotion?

Answer 25

Friction on surfaces

Question 26

What are the 2 suborders of snake necks?

Answer 26

1. cryptodira (draws head in shell) 2. pleurodira (turns head into/under shell)

Question 27

What are the 3 layers of chelonian shell? Why is this important to know?

Answer 27

Epidermal (keratinised) Dermal (mineralised bone in dermis, blood + nerves, metabolically active) Endochondral (ribs, vertebrae, clavicles, inter clavicle - fused to shell, blood + nerves, metabolically active) So that we understand that shell damage is like a fracture and treat it accordingly including pain relief

Question 28

What is the name given to the dorsal aspect of the shell? What is the name given to the ventral aspect of the shell?

Answer 28

Dorsal = carapace Ventral = plastron

Question 29

How does metabolic bone disease usually present in chelonians?

Answer 29

Misshapen shells but remember this has a large impact on the internal structures

Question 30

How many ..... vertebrae do chelonians have? ... cervical ... trunk/dorsal ... sacral ... caudal

Answer 30

cervical - 8 trunk/dorsal - 10 sacral - 2 caudal - <24 (gender specific)

Question 31

Which is male and which is female?

Answer 31

A = male B = female

Question 32

What is a lizards sternum made from? What is the pelvic girdle like compared to domestic species?

Answer 32

Cartilage (can be calcified but not true bone) Very similar

Question 33

Do snakes have pectoral and pelvic girdles?

Answer 33

No (some exemptions for pelvic)

Question 34

Where in some snakes are their vestigial spurs found?

Answer 34

Caudal to their cloaca

Question 35

Where is the pelvic girdle located within chelonians?

Answer 35

vertically orientated within their ribcage

Question 36

Label the diagram:

Answer 36

Question 36

Label the diagram:

Answer 36

Question 37

What types of muscle do snakes have?

Answer 37

- Hypaxial + epaxial muscles - Intercostal muscles

Question 38

What causes metabolic bone disease in reptiles? Is metabolic bone disease just one disease? How does it present in reptiles?

Answer 38

Imbalance in calcium phosphate levels or lack of UVB light No, it encompasses multiple diseases Misshapen limbs and bone deformities

Question 39

What are the treatment aims for metabolic bone disease?

Answer 39

Increase calcium uptake (dusting is supplement not solution) Improve nutrition Allowance for more exposure to UVB light (provides vitamin D3 which improves calcium uptake) Improved husbandry Pain relief