How Companion Animals Have An Identifiable Form

cats have how many bones

about 245 bones

how many bones do dogs have

about 319 bones

major functions of the skeleton

protect internal organs

support the body

provide attachment sites for muscles

osteoblasts

bone formation

osteoclasts

bone resorption

chondrocytes

maintain cartilage

skeletal system- mineral bank

Ca +2 (calcium ion)

P (phosphorus)

skeletal system- blood production

bone marrow (hematopoiesis)

skeletal system- acid-base

by absorbing/releasing alkaline salts as needed

skeletal system- detoxification

heavy metals, toxins

skeletal system- sound management

bone conduction

ex: ear canal

scapula

shoulder blade

humerus

upper arm

radius and ulna

forearm

carpus

wrist

paws

feet

angulation of the shoulder/hind affects ____

gait

sacrum, ilium, ischium, pubis, acetabular bones

components of the pelvis

femur

upper thigh bone

tibia/fibula

shank

tarsus

hock

angulation

the angles created by the bones meeting at various joints, especially at the shoulder, stifle, and hock

a dog being well-angulated or well-turned

a dog exhibiting proper joint angles for its breed

forequarters (thoracic limb) proper angle degrees

45, 90, 20

hindquarters (pelvic limb) proper angle degrees

30, 110

forechest

the portion of the dogs that shows in front of the forelegs (amount varies by breed)

shoulder layback

the angle at which the scapula lies against the ribcage, usually 45 degrees (doesn’t apply to all breeds)

the shoulder angle

the angle between the shoulder and humerus

achondroplastic breeds

about 90 degrees because their elbows lie close to the ribcage and well above the brisket

ex: dachshunds, corgi

working breeds

a more open-angled shoulder because the upper arm needs to be long enough to place the elbow properly under the body so that the legs can converge towards a center line during gaiting

galloping breeds

a more open shoulder because the upper arm often drops quite sharply. Consequently, the elbow will be below the brisket to allow flexibility during the typical double-suspension gallop

ex: greyhound, Irish wolfhound, Saluki

front assembly

when a shoulder assembly is correctly placed, the well-laid shoulder and good shoulder angle will be obvious and there will be a good length of neck and usually some prosternum visible in profile

pelvic angle

the length and set of the pelvic girdle in relation to the spine, often affects the angulation of the whole hindquarters

a moderate pelvic slope

allows a smooth transition from the back through the croup to the hindlegs

hindquarters

most standards have an angle of 90-110 degrees of the hindquarter to bring it in line with the forequarter angulation

the slope of the pelvis can also affect the slope of the croup and the set of the tail

the stifle joint angle

rear angle measured along longitudinal axes femur and tibia/fibula: 110-130 degrees (150 degrees for Chow-Chow)

hock joint

the joint formed with the connection of the tibia and fibula and the tarsals (“pastern”)

straight hock

often accompanied by straight stifle

sickle hock

where the joint is over-angulated, often accompanied by long tibia and or long pasterns

cow hock

when the hocks are set inwards, resulting in a splayed appearance in the back legs

gait

the pattern of footsteps at various rates of speed, each pattern distinguished by a particular rhythm and footfall

most commonly recognized gaits

walk, trot, gallop

other normal gaits

amble, pace, and canter

show ring

when a judge requests an exhibitor to “gait your dog,” the dog is to be led at a trot across the ring in a prescribed pattern

the flying trot (in GSD)

all 4 feet are off the ground for a brief period of time

it’s a faster gait in which the dog hurdles all of its feet off the ground at the same time

extreme angulation for the flying trot

kinematic gait analysis

quantifies the positions, velocities, acceleration/deceleration, and angles of various anatomic structures

kinetic gait analysis

measures the ground reaction forces that are the result of an individual’s steps

cat + dog spines

has 7 cervical vertebrae, 13 thoracic vertebrae, 7 lumbar, 3 sacral, and (22-23 caudal/coccygeal vertebrae for cats)-(20-23 coccygeal vertebrae for dogs)

the extra lumbar and thoracic vertebrae in cats results in

a cat’s higher spinal mobility and flexibility

the cat caudal vertebrae

the tail (a counterbalance to the body during quick movements)

elastics discs

useful for cushioning the jump landings

C-1 cervical vertebra

the atlas; articulates the base of the skull (occiput)

“atlanto-occipital joint” — “yes joint”: allows up and down motion of the head

vertebral subluxation complex (VSC)

the cervical vertebrae that are quite flexible

C-2 cervical vertebra

the axis- the joint between the atlas and the axis is “atloaxoid” or “atlantoaxial” joint

“no joint”- allows side-to-side motion of the head

intervertebral disk disease

a degenerative disease of the spinal column: compression of the spinal cord and spinal nerves

in small breeds- spinal disks can begin degenerating first few months of life

herniated or “slipped” disk

can occur suddenly (1-2 yrs of age); in large breeds (5 yrs), signs continue to worsen

herniated disks

most common in the neck and the middle of the back

herniated disks in the neck

neck pain, stiffness, muscle spasms; mild partial paralysis to total paralysis of all legs

herniated disks in middle of the back

back pain, possible curvature in the spine, reluctance to move; loss of motor control in the hind legs to paralysis and incontinence

cervical vertebral malformation-malarticulation

a compression of the cervical spinal segments

genetic factors and possibly nutrition

disc-associated wobbler syndrome (DAWS)

middle-aged (7 yrs), large-breed dogs (doberman pinschers)

ventral compression of the spinal cord due to the protrusion of one or more caudal cervical discs- “wobbly gait”

cat bones

joints between spinal vertebrae very flexible: aid in climbing, stalking, and pouncing

arched spine allows impressive spring

tail is used effectively as a rudder and for balance … but a Manx does fine without a tail

vestigial clavicle (cat)

enhances mobility of front legs needed for hunting

retained in 2 carnivoran families: canidae + felidae

represents the degenerate remainder of the ancestral clavicle; in the Canidae (dogs, foxes, jackals, lycaon) the clavicle is often absent

a similar situation is present in rabbits and some rodents (guinea pig- Cavia porcellus)

rotating carpals (cat)

allow more varied use of front paws than dogs have

vestigial structure

a biological structure that has lost a major ancestral function and is usually drastically reduced in size

dog clavicle

in dogs, there is no collarbone

the front assembly literally floats on its muscular and ligamentous attachments

this arrangement suits the need for max cushioning and flexibility of the front end of a predator which must catch its fast-moving prey

Type 1 IVVD

the outer layer of the discs harden and damage the disc, allowing it to break easily

Type 2 IVVD

the discs slowly harden over time and eventually start to break down and bulge, putting pressure on the spinal cord