Hindlimb Flashcards
What allows horses to sleep standing up?
Their stay apparatus - can lock legs without muscular energy
What is the passive stay apparatus made of?
Is it in the hindlimb and forelimb?
Tendons, ligaments, muscles with fibrous content
Both hindlimb and forelimb
What are the 3 components of the suspensory apparatus in both the fore and hindlimb?
- suspensory ligament
- sesamoid bones
- distal sesamoidian ligaments
Which component of the suspensory apparatus resists carpal and fetlock extension?
The distal sesamoidian ligament
Where does the suspensory ligament originate and where does it run?
Originates on metacarpal/tarsal 3 and splits into 2 branches attaching to the sesamoid bones and then continuing down further
What type of injury is common in the stay and check apparatus?
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
How do horses remove the weight of their thorax off of their forelimbs?
Through the tendinous layer of the seratus ventralis muscle that suspends the thorax when the muscles relax
What is the check apparatus made up of?
What do the ligaments do?
- superior check ligament ie. accessory ligament of SDFT
- inferior check ligament ie. accessory ligament of DDFT
Resist fetlock and carpal hyperextension without muscular effort
What does patella locking allow?
How many ligaments are involved?
Prevents tibial flexion
3 patella ligaments
How does patella locking work?
Contract quadricep
Patellar fibrocartilage + medial patellar ligament lock over medial trochlear ridge
Stifle locked in extension
Is patellar locking an active or passive process?
Active process
Why could a patellar stay locked?
Poor muscle condition so quadriceps can not contract well enough to unlock patellar
What is the reciprocal apparatus?
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
What are the two tendons involved in the reciprocal apparatus?
- peroneus tertius - cranial (blue)
- superficial digital flexor - caudal (red)
What are some of the musculoskeletal adaptation horses have for speed?
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
What is the calculation for cardiac output?
Cardiac output = stroke volume x heart rate
Organise the following into the correct boxes:
What are Squamata?
What are testudines/chelonians?
Lizards and snakes
Turtles, tortoises and terrapins
What is the quadrate bone in exotic species?
Bone that allows reptiles like snakes to open their mouth fully when eating
What is the difference between mammal and exotic vertebrae?
Mammal - built for rigidity, strength and stability
Exotic - built for flexibility (ie. one occipital condyle for extra head movement)
Do exotic species have ribs?
Yes, they have true endochondral ribs
May also have gastralia which are ribs caudal to the sternum covering the abdomen
How doe bones grow and repair in reptiles?
Growth:
- slow epiphysis, physis nerves close in some specie
- dependant on external factors
Repair:
- very slow, takes months
- less remodelling and periosteal growth
What is a lizard anti predator defence mechanism involving their tail?
What is the problem with this?
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
What are the vertebrae like in snakes?
Do snakes have sternums?
Precloacal - flexible ribs, flexible
Cloacal + Caudal - no ribs
No as they would reduce flexibility
What do snakes rely on for locomotion?
Friction on surfaces
What are the 2 suborders of snake necks?
- cryptodira (draws head in shell)
- pleurodira (turns head into/under shell)
What are the 3 layers of chelonian shell?
Why is this important to know?
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
What is the name given to the dorsal aspect of the shell?
What is the name given to the ventral aspect of the shell?
Dorsal = carapace
Ventral = plastron
How does metabolic bone disease usually present in chelonians?
Misshapen shells but remember this has a large impact on the internal structures
How many ….. vertebrae do chelonians have?
… cervical
… trunk/dorsal
… sacral
… caudal
cervical - 8
trunk/dorsal - 10
sacral - 2
caudal - <24 (gender specific)
Which is male and which is female?
A = male
B = female
What is a lizards sternum made from?
What is the pelvic girdle like compared to domestic species?
Cartilage (can be calcified but not true bone)
Very similar
Do snakes have pectoral and pelvic girdles?
No (some exemptions for pelvic)
Where in some snakes are their vestigial spurs found?
Caudal to their cloaca
Where is the pelvic girdle located within chelonians?
vertically orientated within their ribcage
Label the diagram:
Label the diagram:
What types of muscle do snakes have?
- Hypaxial + epaxial muscles
- Intercostal muscles
What causes metabolic bone disease in reptiles?
Is metabolic bone disease just one disease?
How does it present in reptiles?
Imbalance in calcium phosphate levels or lack of UVB light
No, it encompasses multiple diseases
Misshapen limbs and bone deformities
What are the treatment aims for metabolic bone disease?
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
