VAP practical MT 25-26

Contains the questions and answers from the VAP practical handbook.

What is the length of gestation in the pig?

115 days

Which joint is the pig’s equivalent of the human ‘knee’?

stifle

Which joint is sometimes loosely termed the ‘knee’ in horses and cattle?

carpus

What is the difference between an artery and a vein?

artery: from the heart

vein: to the heart

Of the umbilical arteries and veins, which carry oxygenated blood and which deoxygenated?

Umbilical artery: deoxygenated blood

Umbilical vein: oxygenated blood

Where else do arteries carry deoxygenated and veins oxygenated blood?

Pulmonary circulation

How would the contents of a fetal lung differ from those of a newborn animal that had breathed? How could you tell whether a neonate had breathed using just a pot of water?

Fetal lung: filled with liquid, so would sink

Newborn: filled with air so would float

After birth, the left side of the heart receives blood from the lungs and pumps it around the body. The right side receives blood from the body and pumps it around the lungs. Why do you think this is not the case in the fetus?

The lungs are not perfused well

If you cut through the ventricles you will see that their muscular walls are approximately the same thickness. After birth, the left ventricle becomes much thicker – how does this relate to its change in function after birth?

Systemic/pulmonary resistance

Bos indicus

Indian ox

Bos taurus

ox

Camelus dromedaries

camel

canis familiaris

dog

capra hircus

goat

cavia porcellus

guinea pig

cervus elephas

red deer

chinchilla laniger

chinchilla

dama dama

fallow deer

elephas maximus

elephant

equus asinus

donkey

equus caballus

horse

felis catus (occasionally ‘domesticus’)

cat

meriones unguiculatus

gerbil

mesocricetus auratus

syrian hamster

mus musculus

mouse

mustela putorius furo

ferret

oryctolagus cuniculus

rabbit

ovis aries

sheep

rangifer tarandus

reindeer

rattus norvegicus

rat

sus scrofa

pig

What is a fossa, a trochlea, a tuberosity, a foramen?

ditch, pulley, bump, hole

What are the relative positions of the proximal ends of the radius and ulna in the standing dog?

Radius: cranio-lateral

Ulna: caudo-medial

What are the relative positions of the distal ends of the radius and ulna in the standing dog?

Radius: medial

Ulna: lateral

Why are the radius and ulna more similar in thickness in cats?

Animals that supinate need these bones of similar strength

Why are the radius and ulna fused in ungulates?

do not supinate

In which species are the radius and ulna…

separate

tightly moulded

fused

incomplete?

Carnivores

pigs

ruminants

horses

What is the difference between pelvis and hip?

pelvis is the bone, hip is the joint

How do the iliac crests, tuber coxae and tuber sacrale compare in the dog and ungulates?

Tuber sacrale is the equivalent of the dorsal iliac spines

tuber coxae the ventral iliac spines

What do ‘malleolus’, ‘tibia’ and ‘fibula’ mean?

Little hammer

the needle

front of a brooch

Why might you expect fractures of the pelvis to be multiple?

Because it forms a bony ring, so unless the sacroiliac joint or sacrum is disrupted, there must be more than one fracture

How do the fore- and hind- cannon bones differ in the horse?

The fore is circular in cross-section, hind is flattened into an oval

Which species have scapular cartilage?

Ungulates

Small in carnivores

Which species do not have an acromion?

horse and pig

Which species have a tuber spinae?

horse and pig

Which species have a two-pronged acromion?

rabbits and cats

Which species have a double bicipital groove?

equids and camelids

Which species has a median foramen on the humerus?

cats

What digits do carnivores retain?

1-5

What digits do equids retain?

3

What digits do even-toed ungulates (cattle, sheep, pigs) retain?

3-4

Is brachiocephalicus or latissimus dorsi more massive?

latissimus dorsi

retraction is the power stroke

What other, minor functions do you think brachiocephalicus and latissimus dorsi might have?

Brachiocephalicus: shoulder extension

Latissimus dorsi: shoulder flexion

In which two major domestic species is the clavicle still present?

cat and rabbit

Considering the structure and location of the scapula, how common do you think scapular fractures are?

Rare, since proximal and embedded in muscle

How easy would a scapular fracture be to repair? What treatment would you recommend?

Difficult since inaccessible (surrounded by muscle) and very fragile bone

usually rest

What are the flexor aspects of the…

elbow

carpus

hip

stifle

hock?

cranial

caudal

cranial

caudal

cranial

What extrinsic muscle may also act to flex the shoulder?

Latissimus dorsi

Examine the origins and insertions of triceps on a skeleton. Is it monarticular or polyarticular?

The long head is polyarticular, the other three heads are monoarticular

Minor, secondary roles of triceps?

Flex shoulder

What feature of radius and ulnar anatomy suggests that cats can supinate?

Similar size

unfused

extensive articular facets

During supination, which bone rotates about which?

Radius about the ulna, as the ulna retains a fixed relationship to the humerus

Why are the main muscles moving the digits in the antebrachium and not in the manus itself?

Shifts the muscle mass proximally - cursorial specialisation

Where would be a convenient place to screw a bone plate to fractured radius?

craniomedially - it is subcutaneous here

What is the clinical relevance of extensor of digits I & II?

sesamoid looks like a radial carpal fracture fragment on radiographs

At which joints might SDF, DDF & interossei act?

SDF: proximal interphalangeal joint

DDF: distal interphalangeal joint

Interossei: metacarpophalangeal joint

What are the common vernacular names for the joints in horses?

Knee, fetlock, pastern, coffin

What are the equine equivalents to the pads?

Digital: frog

Metacarpal: ergot

Carpal: chestnut

What is the major difference between the bones of digit I and the others?

2 phalanges

Give two reasons why the palmar/caudal aspect of the manus/antebrachium receives more blood than the dorsal/cranial aspect.

Flexors are supportive/propulsive

pads are for absorbing concussion

Do you think the accessory carpal is a sesamoid in the tendon of flexor carpi ulnaris?

Has a growth plate, so probably not

The accessory carpal is prone to fracture in a particular type of dog. What do you think causes such fractures, and which foot would you expect them in?

Overstrain in the right outer limb on corners

The caudal shoulder joint is one of the commonest sites of osteochondrosis in the dog. In which breeds? What signs might you expect in a dog with a painful shoulder?

Giant and deep-chested breeds

progressive, intermittent forelimb lameness; pain on shoulder extension

State two differences between the biceps tendon and its associated structures in the horse and dog.

tendon has a central groove, interlocking with the ridge in the bicipital groove of the humerus

bursa is continuous with the shoulder joint

What is the difference between a tendon and a ligament?

Tendon: muscle to bone

ligament: bone to bone

In which breeds is the elbow prone to osteochondrosis?

Labrador

German shepherd

Wolfhound

Basset hound

Rottweiler

Two common forms of osteochondrosis involve a failure of the anconeal process or the medial coronoid process to unite with the ulna. How might you differentiate these on clinical examination? What radiographic views might you take to ‘skyline’ these prominences?

Pain on elbow flexion or extension

radiograph flexed and extended (also maybe slightly rotated due to coronoid process)

The canine lateral humeral condyle fractures more often than the right, and usually there are two fracture lines. Why?

Smaller

usually fractures through foramen

The carpus contains three major joints. What are their anatomical names, and how much movement occurs at each?

Antebrachiocarpal joint > intercarpal joint > carpometacarpal joint

The flexor aspects of the carpus, MCPj, PiPj and DiPj are all on the same aspect – which is it?

palmar

Which end of the antebrachium grows most rapidly in puppies?

distal

The carpal canal is roughly triangular in cross section. What are the three structures that form the canal and what tendons does it carry?

Carpal bones (dorsal), Accessory carpal (lateral), Flexor retinaculum (palmar);

SDF, DDF, FCR

On a rather different scale, find the collateral ligaments and the complex ligaments running distally from the accessory carpal. The force of which muscle do they transmit?

Flexor carpi ulnaris

Note the complex articular facets in the joint. How does its bony constitution differ from the dog?

radius and ulna not fused; 1 vestigial, if present

Apart from any carpal bones, there should be nine bones in your specimen. Give their anatomical and common names. Which ones can you palpate in a live horse (or your specimen for that matter.)

Metacarpal III (cannon bone)

Metacarpal II (medial splint bone)

Metacarpal IV (lateral splint bone)

Lateral proximal sesamoid bone

Medial proximal sesamoid bone

P1 (long pastern)

P2 (short pastern)

P3 (coffin bone)

Distal sesamoid bone (navicular bone)

All can be palpated apart from P3 and navicular bone

Which splint makes more contact with the carpal bones?

Metacarpal II

articulation with the carpus is larger and less oblique

more force transmitted through it

This tendon can pull with so much force that it can pluck the extensor process from P3. What signs would you expect from such an ‘avulsion fracture’, and how might you repair it?

often just swelling

screw back on if large fragment

The neurovascular bundles, and their v.-a.-n. composition are very important clinically. Do you know any reasons why?

local analgesia

neurectomy for navicular disease

taking pulse

abnormal pulse in laminitis

What range of movement can the fetlock joint undergo?

120^o flexion and extension

Arrange the following in descending order of incidence of osteochondrosis in horses.

Hock > stifle > shoulder > fetlock > C3-7

The cannon, long pastern, short pastern and coffin are ‘orientated’ the same way round. Which is always the distal articular surface – is it the trochlea or the fovea?

trochlea is distal, as in dogs

Why “navicular”? Is it a sesamoid?

boat shaped

not in tendon but not really in ligament either

What other ligaments attach navicular to the rest of the digit?

2 laterals, 1 impar

What are the functions of the navicular bone?

moving DDFT away from the fulcrum of distal interphalangeal joint to increase torque

transmit weight down to frog

When might the ergot touch the ground?

on extreme weight/impact bearing on soft ground

Why do you think the three commonest fractures of racehorses are…

i. microfractures of the dorsal cortex of MCIII

ii. slab fractures of the cranial faces of the carpal bones

iii. fractures of the proximal sesamoid bones

i. much weight transferred down dorsal aspect; flat racers are young with fine, thin cannons

ii. same dorsal aspect argument; also carpus locks in straight position and the front faces of the bones transmit huge forces

iii. overextension of the fetlock in immature racers

Why does P1 often fracture sagitally, but P2 fracture in a different plane?

P1 is ‘log-split’ by ridge on trochlea of MCIII

P2 palmaroproximal process is avulsed by suspensory apparatus/SDF

Where is the sacrosciatic ligament?

sacrum to sciatic tuberosity

How does sacrosciatic ligament differ in ungulates?

broad sheet extending to the pelvis

How do the insertion and function of superficial gluteal differ in horses?

inserts on the 3rd trochanter and acts as a hip flexor