How companion animals walk

flashcards regarding bones, joints + teeth

the appendicular skeleton

legs + feet

the axial skeleton

the main axis of support, the head, neck, spine, ribs + sternum

the visceral bones

small bony parts (inner ear)

grow plates

long bones, epiphyseal plates, produce cartilage which is converted to bone as the dog grows

puppy bones

depending on the breed, puppies bones continue to grow and develop until about 1-2 yrs

grows rapidly until about 6 months then slows down

growth plate closure

don’t begin trying puppy until around 10-18 months

closure happens around late puberty

growth plates close after exposure to hormones

spayed + neuters

spay + neuters occurring prior to puberty

delay in the closing process of growth plates

delay neutering in large dog breeds

pastern

phalanges; should not be used in reference to dogs and cats (used for horses + live stock etc)

front pastern

metacarpus

rear pastern

metatarsus

paws and claws

dogs + cats are digitigrade: walk on their toes

humans, bears are phantigrades: walk on plantar surface of foot

hyperextension or subluxation/luxation of the pasterns

seen as a flat-footed condition wherein the dog walks on the palmar surface on its wrists

palmigrade or plantigrade stance

normally an acute phenomenon caused by a traumatic event that ruptures the palmer ligaments in a front foot.

ligament degeneration —> dog becomes progressively palmigrade

carpal hyperextension in adult cats

usually associated with a fall from a significant height; diabetes neuropathy in cats

early stages is reversible

treatment is like dogs, fusion of the wrist; cats more mobility in the joint

overangulation

steep pelvis, steep lumbar spine angle, low hip + knee, overlong tibia

dog paws + claws

four functional toes (phalanges) on each foot and one that is vestigial (dewclaw)

cat paws + claws

generally, five toes on front feet and four on back feet

P3 toe

produces claws, important for traction + digging (dog & cats) and for cats: climbing, hunting, defense

elastic ligament in cats

located between distal end of P3 and middle phalanx (P2) that allows contraction and extension of claws

the dewclaw

candiae + felidae: the thumb is the dewclaw

shorter than the other digits and doesn’t contact the ground

5th digit on a paw

can be on front and/or hind legs

dewclaw is not reduced enough to satisfy the _______

1st criterion for vestigiality

the dewclaw does not satisfy the ____

(lost of specialized morphology)

2nd criterion of vestigiality

the dewclaw does not satisfy the 3rd criterion because _______

lost of salient ancestral function

dewclaw removal

removal at 2-3 days is generally standard (attachment is small then)

double dewclaw

refers to a 5th and 6th digit on the paws of some breeds (great pyrenees, beaucerons, lundehunds)

folklore: have a natural immunity to the venomous effects of snake bites it the dewclaws remain intact

Polydactyly

cats that lave more toes than the average cat (5 toes on front paw, 4 toes on back paws)

result of a single, autosomal dominant gene

two types: postaxial + preaxial

postaxial polydactyly

extra digit on lateral side of the limb; “patty foot”

preaxial polydactyly

extra digit on the medial side of the limb; “thumb cats” or “mitten cats”

squitten cats

kangaroo cats/ (“squirrel” + “kitten”)

radial hypoplasia/foreleg micromielia with “patty feet” or “humburger feet”

cats have short forelegs, genetic mutation

kittens may be unable to knead effectively to stimulate milk flow from the mother

radial hypoplasia

underdeveloped radius bones

foreleg micromelia

small forelegs

radial aplasia

absent radius bones

radial agenesis

failure of radius bones to form

brachycephalic skull

a short, wide, round skull, short muzzle (bulldog, pug, Persian cat, exotic short hair cat)

mesaticephalic/mesocephalic skull

medium skull and muzzle (labrador, DSH cat)

dolichocephalic skull

a long, narrow skull, long muzzle (greyhound, Siamese cat)

Cephalic Index

the measure of the width vs the length of the cranium

The Craniofacial ratio

compares the size of the cranium to the length of the muzzle

cat face shape(s)

facial features of cat not as neoenized as those of dogs (baby scheme response)

(with the exception of the Scottish fold)

hypertelorism

wide spaced eyes, due to an underlying disease

some cats may have cleft palates

usually shortens lifespan, depending on severity

joint

formed when two bones are brought together and held in place by supporting tissues

movable union between two bones

articulations/joints

bones are held together by ______

ligaments

what are three types of joints

fibrous, cartilaginous, synovial

Canine hip dysplasia (CHD)

a multifactorial abnormal development of the coxofemoral joint

characterized by joint laxity, degenerative joint disease (DJD) or osteoarthritis (OA)

pathophysiologic basis

a disparity between hip joint muscle mass and rapid bone development

bone spurs

stifle joint: femur and tibia/fibula

patella/kneecap: knee extension

luxate: comes out of the groove and usually shifts medially

patellar luxation

hereditary disorder in dogs + cats: ectopic development of the patella medial or lateral to the trochlear groove of the femur

when the dog’s kneecap (patella) is dislocated from its normal anatomic position in the groove of the thigh bone (femur)

can be returned to its normal position once the quadriceps muscles in the hind legs of the animal relax and lengthen

most common in toy + mini dog breeds (dog that have this should not be breed)

can occur in cats of all ages and breeds

medial patellar luxations

can be involved with a reduced coxofemoral angle (coxa vara)

coxa vara

the femoral d, almost perpendicular to the shaft.

this deformity is frequently seen in patellar luxation, or ”lipped stifles”

dog teeth

dogs are carnivores and have teeth that reflect this

pet dogs have been turned into omnivores as most dry dog foods contain substantial amounts of plant material

do have grinding surfaces on their molar teeth

cat teeth

cats are obligate carnivores although pet cats consume a lot of plant material

they do not have a grinding surface on any teeth

brachydont or low-crowned teeth

dogs and cat have these type of teeth

a crown above the gingiva, constricted neck at gum line and root embedded in the jawbone

enamel is the hardest substance in the body

crown is incased in enamel

hypodont or high-crowned teeth

lagomorphs and rodents (radicular hypsodent) have these type of teeth

lagomorphs have a white incisor enamel color

rodents have a yellow incisor enamel color

cementum

calcified connective tissue

dentin

a bonelike material is under the enamel and makes up most of the tooth; it can transmit pain to the pulp if exposed —> tooth sensitivity

the pulp cavity contains

blood vessels, lymphatics, nerves

dogs and cats have 4 types of teeth

heterondonty- different functions

incisors, canines, premolars, molars

incisors teeth (I)

cutting and nibbling food

Canines (C)

holding and tearing food

Premolars (P)

cutting, holding, and shearing food

Molar (M)

grinding food (dogs)

deciduous set of teeth

milk teeth, baby teeth

permanent set of teeth

adult teeth

dental formulae

used to indicate the number of each type of tooth for a given species

Order: I, C, P, M

the maxillary arcade or upper jaw is listed over the mandibular arcade or lower jaw

Individual teeth can also be denoted:

the 1st lower incisor would be I1, and the 2nd upper molar would be M2

canine permanent teeth count

42

canine deciduous (baby) teeth count

28

feline permanent teeth count

30

Feline Deciduous teeth count

26

dental formula

2( I/I, C/c, P/p, M/m )

kittens + puppies deciduous teeth begin to erupt at _____ weeks , and permanent teeth begin to emerge at ______ months

3-4

by 24 weeks of age (about 6 months) all _____ teeth have emerged

permanent

the 1st premolars and molars erupt as permanent teeth without deciduous predecessors

carnassial teeth

enlarged and often self-sharpening edges to pass by each other in a shearing manner to permit the more efficient consumption of meat (sectorial teeth)

carnassial teeth in dogs

the modified 4th upper P and the 1st lower M

carnassial teeth in cats

3rd upper P and the 1st lower molar

carnassial tooth abscess

the large carnassial tooth (4th upper P) has 3 roots

carnassial tooth infections and/or abscess- the individual root usually involved; the front one that is closest to the skin below and in front of the eye

retained deciduous tooth

a deciduous tooth should be lost before its permanent replacement appears

occurs when a carnivore has both a permanent and deciduous tooth

it needs to be removed surgically to prevent abnormal alignment of the permanent tooth

class 1 malocclusions

both jaws are a proper length and do not result in any over or underbite.

individual or multiple teeth maybe crowded, rotated, or misaligned

class 2 malocclusions

“overbite”: some or all the maxillary (upper) teeth are located in front of the mandibular (lower) counterparts

class 3 malocclusions

“underbite”; some or all of the maxillary teeth are located behind the mandibular incisors or canine teeth

gum trauma and tooth-to-tooth contact

reverse scissor bite

considered normal in breeds such as boxer, shih tau, pug, etc