NMSK - Behaviour a movement

What are 2 components when considering welfare?

Physiological components and behavioural components

Why is understanding behaviour important?

• provides an insight into an animal’s emotional state and welfare state

• law and legal obligations

• client, practice and human-animal bond

• clinical and surgical success

• minimising negative experiences of a vet clinic

What 2 behavioural competencies should graduate vets show

Do no harm

Apply ‘behavioural first aid’

How do we assess welfare

Behaviour, physiology, longevity and reproduction

How can we use locomotion as an indicator?

• •evaluate what is normal/abnormal
  •assess gait patterns
  •identify gait adaptations - e.g. lameness
  •performance indicators
  •welfare indicators

what are some locomotive indicators of pain

time spent lying down, no. times food stamped, no. ear flicks and time walking (restless)

list some examples of the impact of behaviour on NMSK system

• stereotypical behaviour (e.g. weaving leading to worn feet/muscle injuries and awkward weight bearing leading to musculoskeletal system remodelling itself in response)

• Scales to Assess Paint and Quality of life in companion animals

• Success of operations - pre/post-op considerations and prognosis, ensuring gentle exercise

what are some things to consider before assessing locomotion

• space available

• surface conditions (firm (can listen to foot falls and assess gait pattern), level, non-slip)

• age of animal

• any medical conditions

• handler

• speed of gait (slow or fast)

How do you assess locomotion

• visual observation, analysis equipment (high speed treadmills, video cameras, data analysis software, force plates) - vets don’t tend to use these

• We can assess quality and divergence from the ‘norm’.

Compare using human observation to technical equipment

Human observation:

• subjective, biased

• frame rate - can miss detail

• low technical effort and convenient

• requires experience

• low cost

Technical equipment:

• measurable

• objective, less bias

• required dedicated equipment, space, resources, personnel

• higher cost

What do we as vets need to do for assessing locomotion?

Get good at observing it and recognising what’s normal/abnormal

observe lots of animals

familiarise yourself with the processes

EXPERIENCE

be able to describe patterns of locomotion

What do we mean by gait? Give an overview

The specific patterns of footfalls during locomotion - walk, trot, canter

They change with speed

Characteristic sequences

Strides take place within a gait

Define ‘stride’

Complete cycle of movement

what are the 2 phases of a stride

stance phase (weight bearing limb)

Swing phase (non-weight bearing limb)

Describe the walk gait
- How many beats ?
-Symmetry ?
-Sequence of foot-falls

• 4-beat

• symmetric

• RH-RF-LH-LF

• never more than 3 or less than 2 limbs weight-bearing at any one time

• centre of gravity always been a triangle of weight bearing feet.

Describe the trot gait
- How many beats ?
-Symmetry ?
-Sequence of foot-falls

• 2 beat

• very ancient pattern seen in horses

• symmetric

• diagonal gait

• body supported alternately by left and right diagonal pairs (LH and RF, RH and LF)

• period of suspension b/w successive stance phases

• Marked axial twisting (resisted by design of axial system - evolution)

Describe the canter gait
- How many beats ?
-Symmetry ?
-Sequence of foot-falls

• 3 beat

• asymmetric

• rocking horse motion:

RH RF+LH LF

LH LF+RH RF

• one moment of suspension, after single forelimb leaves the ground, prior to single hindlimb contact

• lead leg - L/R

• one diagonal pair

• 2 limbs out of phase

Describe the gallop gait
- How many beats ?
-Symmetry ?
-Sequence of foot-falls

• fast, 4 beat

• asymmetric gait

• horses usually lead with their inside leg around a turn (called the lead leg)

• moment of suspension

What is meant by the moment of suspension?

• period when no feet are in contact with the ground e.g. fast trot, canter or gallop

• normally one per cycle

• greyhounds and cheetahs have 2 per gallop cycle

what are the 3 kinds of gallop

1. Transverse - LH RH, LF RF* (*one moment of suspension

2. Rotary - RH LH* LF RF* (*two moments of suspension)

3. Counter rotary - anticlockwise footfalls LH RH, RF, LF (asymmetric motion)

Who uses each type of gallop

Transverse - dogs at low speed, horses (odd-toed ungulates) and cattle (large even-toed ungulates)

Rotary - all cats, dogs at high speed, gazelle, antelope (small, even-toed ungulates), running rodents - in a horse it’s called a disunited canter

Counter-rotary - greyhounds on the track (race anticlockwise)

Why may gait change?

• physically necessary (limb flied off the ground - pendulum effect, centrifugal force acting upwards and froude number = ratio of inertial force: gravitational force (>1 = suspension phase)

• Metabolic advantages - optimal speed for each gait at which energy cost is minimal. (treadmill study - measured O2 consumed at each gait). Respiratory pattern and locomotion/respiratory coupling

• Mechanical advantages (reduced bone strain)

Explain the neurological basis of limb coordination

• sensation: vision, vestibular system (inner ear, balance orientation), mechanoreceptors (touch), nociceptors (pain), proprioceptors (body position)

• Motor response to stimuli: Nervous system (in/voluntary control and reflexes), central pattern generators, brainstem, cerebellum (balance), constant monitoring of muscle length and tension (muscle spindles and golgi tendon organs)

how are equines adapted to high speed locomotion?

• increase stride length: distal limb elongates, mobile scapula (increase length of limb, whiplash effect (small motion of the upper limb > flick of the lower limb)

• Minimise limb mass - most of the work done involves accelerating and decelerating limbs, muscles positioned proximally (near pivot-point), reduced number of bones in limb.

• Adaptions decrease mass (inertia) of lower limb.

• Conservation of energy - whiplash effect, long tendons (transfer load, shock absorbers and energy store), stable joints (limit range of movement but little extra support is required).

• Relatively rigid spine/sacroiliac junction: large gut, large body mass, transfer of energy from powerful hind quarters which minimised up and down movements of the body during locomotion.

how are canines adapted to high-speed locomotion

• elongation of limbs (mass proximal)

• digitigrade (claws for catching prey, claws may assist grip)

• flexible back (arches and straightens which increases stride length), no gut restriction

• tail - assists with balance when out of balance

what are some clinical consequences of adaptions in equines

• low safety margins - bones and tendons (fractures and tendon strains)

• little soft tissue covering distal limbs - poor wound/fracture healing

• little soft tissue to absorb impact loads (joint injuries/osteoarthritis

Outline the evolutionary adaptions of horses

• survive on prairies and grasslands

• flight not flight

Detect dangers = good hearing, sight and smell

Sleep standing up: stay apparatus

Speed and endurance: cardiac, musculoskeletal and respiratory

Survive on large volumes of poor-quality roughage

what well developed senses do horses have?

• large eyes, far back on an elongated head = high visual acuity and wide field of view

• excellent hearing - mobile ears

• accomplished sense of smell

how are horses adapted to sleep standing up?

• stay apparatus

• uses tendons, ligaments and muscles with high fibrous content

• very few muscles used = lower energy demand

If the muscles were used = lots of energy needed, which would be disadvantageous

Outline what is involved in the passive stay apparatus of both the fore- and hindlimbs

Forelimb: serratus ventralis, check apparatus

Hindlimb: patella locking and reciprocal apparatus

BOTH: suspensory apparatus

Outline the suspensory apparatus

1. suspensory ligament (interosseus muscle in dogs), splits into the sesamoidian ligaments) at the sesamoid bones

2. distal sesamoidian ligaments resist carpal and fetlock extension without muscular effort

3. prevents movement

what sesamoidian ligaments are there?

1. Intersesamoidian

2. Short sesamoidian (sesamoid to P1)

3. Oblique sesamoidian (sesamoid to bottom of P1)

4. Straight sesamoidian (sesamoid to P2)

How may suspensory branch desmitis/sesamoiditis appear on an ultrasound/radiograph

Ultrasound:

• no clear ligament/bone barrier

• hypoechoic areas within the long white lines

• broken bone/ligament border

Radiograph:

• can see radiolucent areas on the bone

• see ostephytes

• abnormal bone growth

Outline the serratus ventralis and the role it has in the stay apparatus

• only in forelimb

• forms a link between the costal side of scapula and the ribs and vertebrae

• contains a tendinous layer

• suspends the thorax when the muscles relax - due to tendinous quality, prevents the trunk from sinking

• two parts of the muscle: cervical and thoracic.

outline the check apparatus and its role in the stay apparatus

• forelimb only

Superior check ligament = accessory ligament of the SDFT

• palmar radius to the SDFT in the distal radius

• resists carpal and fetlock extension without muscular effort

Inferior check ligament = Accessory ligament of DDFT

• palmar carpus to the DDFT mid metacarpus

• resists fetlock extension without muscular effort

How may we identify check ligament desmitis?

On observation:

• swelling may be visible on the limb where theses ligaments are located

Ultrasound:

• may appear larger than normal with evident hypoechoic areas which indicate tearing

Outline patella locking

When relaxed:

• the patella is free to slide within the trochlear groove as stifle moves

When locked:

• medial patellar ligament sits over the proximal medial trochlear ridge

• Stifle can no longer bend

• Patella is locked in position without muscular effort

is patella locking active? how is it controlled and undone?

yes it’s active

Controlled: - quadriceps extends, patella rotates medially

Unlocked: Quadriceps flexes, patella rotates laterally

What is upward fixation of the patella?

• when the patella locks into place and won’t unlock

• Horse will struggle to walk, with stifle and hock extended

How can we treat upwards fixation of the patella?

• cut the medial ligament

• over time it fuses again, but will be shorter and fatter, which prevents unwanted locking

in what kind of horses is upwards patella fixation more likely?

Horses with a straight hindlimb conformation e.g. minatures and shetlands

Weak quadriceps - older and non-athletic horses and breeds.

Outline the reciprocal apparatus

Only in the hindlimb

two tendinous cords cause united movement of the stifle and hock

• peroneus tertius - cranial

• superficial digital flexor - caudal

Powerful proximal muscles act upon distal limb

When stifle is locked, hock is also immobile:

• stifle extends, so must hock (proximal SDF is pulled, so is proximal calcaneus)

• stifle flexes, so does hock

How can we identify a ruptured peroneus tertius?

• upon examining hindlimb

• stifle is flexed

• hock remains extended

How are horses adapted for speed?

Increased stride length:

• long legs (especially distally)

• mediolaterally flattened thorax (legs can slide easily along the thorax body)

• scapula positioned laterally and free to swing

• vestigial ulna (increases lever action of the triceps)

Increase stride rate:

• reduced distal limb mass (single digit)

• muscle weight proximal

• long tendons (pulley effect)

Minimise energy wastage:

• single plane of movement of limbs

• stretched tendons store kinetic energy as heat - can act as springs

what two things factor into speed of an animal?

• stride length

• stride rate

Outline some factors of the thoracic limbs in comparison to the hindlimbs

• carry more static body weight - translate horizontal velocity provided by hindlimbs, minimise wasteful vertical energy

• shorter and straighter than hindlimbs (no bone articulation to skeleton - act as suspension)

• broader, more rounded hoof

• energy storage (tendons)

Outline some factors of the hindlimbs in comparison to the forelimbs

• provide forward impulsion of the horse

• direct bone articulations

• narrower, more pointed hoof

What is meant by the power train

Other adaptions of the horse for high speed

• heart

• lungs

• muscles

How do horses have efficient airflow?

• less complicated nasal passage

• easy access to trachea

• muscles can dilate the nostrils

• straight line from nostrils to trachea

what affects cardiac output?

CO = SV x HR

stroke volume x heart rate

why are horse hearts so well adapted for speed and high CO?

• 2% body weight

• SV is closely related to heart size

• SV only slightly increases during exercise, HR increases a lot

What is:

Heart size (% body)

Resting HR

Max HR

Increase in HR

resing CO (L/min)

max CO (L/min)

increase in CO

In a horse

a) 2%

b) 32 bpm

c) 240 bpm

d) 7.5

e) 35L/min

f) 280 L/min

g) 8 x increase in CO

why do horses have so many muscles?

• create lots of KE

• store KE as heat - act as springs - return on the next stride?

what do we need to be careful of with horses due to their adaptions?

• horses have been adapted to the very limits of optimal function

• they’re easily pushed past the limit

  Easily injure:

• Stress fractures

• tendon tears

why do tendons tear?

Hyperthermia

• very few cells and blood vessels

• Due to high KE, high temperatures reached, more prone to injury

Common locations:

• Half way down cannon bone in the middle of the SDFT

Name 4 other adaptions of horses

• long teeth continually erupt - hyposodont

  (large grinding surface to reduce stem length)

• long GI tract - hind gut fermenters, can digest poor quality roughage

• Excellent thermoregulators - efficient sweat glands

• Breed variations: size, shape, coat length, dietary requirements, sensitivity to medications.

what features have been highly conserved during evolution?

Relative position of CNS and GIT:

• invertebrates: CNS below GIT

• Vertebrates: CNS above GIT
  

4/6/8 legs

segmentation

head-tail orientation

why do vertebrate animals e.g. dogs and cats have the digits/forelimbs they have?

Forelimbs:

• change in weight placement

• Limbs have moved further from the head - as head has extended away - now have necks

  Digits:

• tend to be teh same length: due to weight placement and the fact limbs are under the body - not on the sides

Outline evolutionary adaptions in the cat and dog in the pectoral girdle

Scapula:

• now a limb bone

• laterally flattened

Coracoid:

• fused and part of the scapula in mammals = coracoid process

Clavicle:

• many variations in mammals

• not in dogs, present in cats (very small/cartilaginous)

Interclavicle:

• derived from skin armour, now on the cranial end of the sternum

what are some general cursorial specialisations?

• anatomical (evolutionary) adaptions for running along the ground

• longer limbs (there is an optimal length)

• reduced lower limb mass

• recruitment of scapula as a limb bone

• loss of clavicle

give 2 adaptions of the proximal forelimb for cursorial specialisation

no clavicle (or rudimentary)

• allows scapula to become an extra limb bone

Scapula vertical against lateral thorax:

• acromion is less prominent than primates and fossorial animals

• shoulder joint constrained by muscles to pro/retraction

what is an important rule of evolution?

• You can’t change the nerve supply

• nerve that supplies something will move with it during its adaption

name some cursorial specialisations in the carnivore distal forelimb

limited pronation/supination in dogs, more in cats

• reduces muscle work since antebrachium is more stable

• cats can do this better because they’re ambush predators, therefore grappling with their prey is more important

Radio-carpal joint has limited abduction/adduction:

• far less than primates, more in than in horses

Digitigrade:

• accessory pad becomes redundant

• plantigrade: tarsus/metatarsus/phalanges on ground

• digitigrade = phalanges on the ground

• unguligrade = only P3 on the ground

what is meant by a)plantigrade b)digitigrade c)unguligrade

• plantigrade: tarsus/metatarsus/phalanges on ground

• digitigrade = phalanges on the ground

• unguligrade = only P3 on the ground

what are some cursorial specialisations in the carnivore hindlimb?

• small abdomen = larger hip movement

• hip joints are more mobile

• strong stifle joint, doesn’t lock

• large muscles for acceleration and high speed

• limb joints move independently

• strong gastrocnemius supported by long hip extensors

compare the hip joint in carnivores and herbivores

Carnivores:

• very good RoM

• angled femoral neck

Large herbivores:

• much more supportive

• asymmetric femoral head

• femoral neck is more compact and vertical

• limited RoM

Outline some evolutionary features of dogs

1. able to survive hot and cold - adverse conditions

2. diet - anatomically carnivore, actually omnivore

3. ability to locate prey - hunt at dawn/dusk/night, good senses

4. stalk prey - soft footed, posture, controlled MSK movements

5. catch prey: work as a team, run to fatigue hunting strategy, turn quickly

6. kill prey: strong jaws/teeth

outline some MSK adaptions for function in dogs

• muscles - fast twitch fibres for speed

• slow twitch fibres for endurance

• mixed type fibre IID

• rely more on fat stores than glycogen for muscle energy

• laxity and flexibility of joints for posture and manoeuvrability

• light body frame

• long limbs - jumping leverage

• tail for balance

• flexible neck = wide range of vision

• muscles to ears to locate sound

  breed conformation and differences

Outline cat evolutionary factors

• evolved from territorial, solitary, hunting cat

• able to survive dry conditions (water retention, urine conc)

• obligate carnivores

• good senses and hunt at night/dawn/dusk

• stalk prey: posture, soft footed, controlled MSK movements

• catch prey: jumping, standing start to fast running, turn quickly, flexibility, claws

• kill prey: claws, jaws

• equipped to defend territory: marking, signalling, fighting

why can’t cat species run for a long time like dogs?

• heat generated can’t be removed quickly enough

• run very quickly but for short periods of time.

Outline some MSK adaptions of cats (1)

1. type Ii fibres for speed - short bursts, anaerobic

2. IIA fatigue resistant

3. IIB - power but fatiguable

4. laxity/flexibility in joints - 3% elastin content (1% in dogs)

5. light body frame - wider medullary cavities and thinner cortices in long bones.

6. long limbs - more cylindrical than dogs

7. tail for balance

8. flexible ligament - no nuchal ligament = greater range of motion

Outline some MSK adaptions in cats (2)

9. muscles to ears to locate sound

10. retractable claws to secure prey

11. greater range of movement in the spine and hsoulder

12. longer and more slender vertebrae

13. broader and shorter scapula

14. weight bearing is more evenly shared b/w front and back limbs (in comparison to dogs)

15. antebrachium range of pronation is 45-55 degrees

16. masseter muscle = strongest depending on definition.

what is the scapula equivalent to

the pelvis

how have the pelvis and scapula developed differently in evolution?

pelvis: wasn’t attached, now is

scapula: was attached, now isn’t

• to axial skeleton

what is the humerus the equivalent of in the hindlimb and what is its latin name?

• femur

• stylopodium

what is the radius/ulna the equivalent of in the hindlimb and what is its latin name?

• tibia/fibula

• zeugopodium

what is the latin name for the carpus/tarsus, metacarpus/tarsus and phalanges?

• autopodium

Outline anatomical difference in dog and cat triceps brachii

Dog: 4 heads: accessory, medial, lateral, long

Cat: 5 heads (lateral head is in 3 parts), no accessory

Outline anatomical difference in dog and cat radius and ulna

• dogs can’t supinate as much as cats

Outline anatomical difference in dog and cat manus/Pes

• Digit I small/absent

• digits III and IV longer than II and V

• paired sesamoid bone at each McPh/MtPh joint

Cats:

• claw retraction by hyperextension of DIP joint

• natural position is retracted — dorsal elastic ligament

• extended by pull from DDFT

Outline anatomical difference in dog and cat shoulder/elbow

Cats:

• Acromion has 2 processes - hamate is distal, suprahamate is flat and proximal

• Coarcoid process - beak-like, extends craniomedially from glenoid cavity (risk of fracture)

• Vestigial clavicle: small ossicle

• Supracondylar foramen: proximal to medial epicondyle (medial nerve and brachial artery pass through)

• Ulnar nerve: lies under the medial head of triceps

• No supratrochlear foramen in olecranon fossa (less likely to fracture distal epiphysis)

• Incomplete ossification of humeral condyle

Outline anatomical difference in dog and cat brachioradialis

cats:

• well developed - elbow flexor supplied by radial nerve

• because cats climb trees.

Outline anatomical difference in dog and cat hip/thigh

• round ligament supplies significant blood supply

• muscles around the hip are broader

• tensor fasciae lata needs longer incision and vastus lateralis greater subperiosteal elevation

• caudofemoralis muscle is caudal to gluteal group, cranial to and acts with biceps femoris

• sartorius muscle: single in cat (2 in dog), lat approach to shaft of femur

• sacrotuberous ligament - absent in cats (sacrum to tuber ischium in dogs)

• acetabulum is load-bearing central and caudal thirds (dog is cranial third)

Outline anatomical difference in dog and cat stifle

cats:

• poorly or unmineralised sesamoid bones

• CrCl is larger than caudal

Outline anatomical difference in dog and cat tarsus

Cats:

• no long component to medial and lateral collateral ligaments just two short components

Outline anatomical difference in dog and cat tibialis cranialis and extensor digitorum longus

• united in cats

Outline anatomical difference in dog and cat flexor digitorum profundus

• tibilais caudalis stays separate with its own tendon

Outline anatomical difference in dog and cat soleus

• origin with DDR, inserts with gastrocnemius in cats

• not really present in dogs

Outline anatomical difference in dog and cat flexor digitorum superficialis (SDF)

• cats have extra muscle fibres distal to tarsus

Outline anatomical difference in cats compared to dogs: axial system:

Flexible lumbar region: increases stride length

Lower gut mass: increased RoM of hips

Nuchal ligament reaches C2 in dogs: not to skull, no laminar part, same function to suspend head and neck in front of the body

No nuchal ligament in cats - lots of fast muscle fibres instead

why are the thoracic spinal processes angled?

• applies weight downwards

• enables the head and neck to be supported

Outline anatomical difference in dog and cat neck and spine

Neck:

• no nuchal ligament in cats- prone to ventroflexion when weak

• Dogs nuchal ligament runs from C1 to T1 spinous process

  Spine:

• more flexibe IV discs in cats - 20% length (15-17% indogs)

• longer cord in cats relative to vertebral column in dogs

what is meant by a congential disease?

• exists at or before birth usually through heredity as a disorder.

• acquired at bird/during uterine development usually as a result of environmental influences

what is meant by a hereditary disease

• genetically transmitted from parent to offspring

what is meant by development of orthopaedic conditions

• normal at birth and the condition develops during growth (usually early post-natal period)

what is meant by dysplasia

abnormality of development

what are some factors that predispose cats/complicate MSK diseases in cats

Lifestyle:

• climbers

• fighting

• sleeping under cars

• running across roads

Diet:

• excess/insufficient nutrient intake

• all meat = nutritional secondary hyperparathyroidism

• ventroflexion of neck with thiamine deficiency

• multiple extoses in hypervitaminosis A

Obesity

Ageing changes

Metabolic problems - neck ventroflexion in hypokalaemia

How do developmental MSK diseases compare in cats to dogs?

• rare

• congenital luxated patella and pectus excavatum due to taurine defiency

How does treatment of ulna and radius fractures differ in cats and dogs

Cats need 2 plates, as radius and ulna aren’t fused

Only 1 plate in dogs because R +U are linked by fibrous tissue, providing stability.

what factors predispose/complicate MSK diseases in dogs

• size/weight - biomechanical forces

• genetic conformation

• activity

• diet

• obesity

• trauma

• ageing changes