Understanding the Anatomy, and Home Examination of Pets
In this module you will learn:
The anatomy of the dog
How to carry out a physical examination of your pet
Common issues to check for
The importance of trimming claws, and how to do it yourself
The signs and causes of lameness and limping
One of the most important aspects of pet care is the ability to identify whether problems are minor, or require professional intervention.
As discussed in Module 1, effective first aid can make a real difference in the outcome of an emergency, until it is possible to get the animal to a vet. In the event of a crisis, time is a luxury that is often not available. Lack of preparation can result in stress and pain for both owners and pets.
The first step in improving your ability to handle an emergency, and which will also assist with daily care, is a working knowledge of your pet’s anatomy. This will also enable you to identify when your pet needs medical attention.
This module will explain the anatomy of the dog, detail the steps involved when making a complete physical examination of your pet, and discuss common issues that you should look for.
2.1 The anatomy of a dog
While it is not necessary for pet owners to complete a course in physiology, they should consider familiarising themselves with the basic anatomy of their dog. Looking at your dog’s frame should enable you to be able to
identify the parts described.
Dogs have many of the same organs, bodily processes, and anatomical parts as humans. As with humans, the heart pumps the blood around the body; the lungs are necessary for breathing; the liver removes toxins from the blood; the kidneys regulate the blood’s water and wastewater content.
Dog’s digestive system
A dog’s digestive system is similar to a human’s, although there are some differences. The canine digestive system is the shortest of all mammals, and so the entire digestive process takes around 8-9 hours.
The key parts are:
- Mouth: dog’s mouths are different from humans’. Their teeth are designed to tear and bite off large chunks of food, chewing is minimal, and saliva plays little part. Saliva is mainly used for the cooling process, as the tongue is one of the few places that dogs can effectively lose heat.
- Oesophagus: the pipe which transports food from the mouth to the stomach.
- Stomach: where food is digested. It contains high levels of hydrochloric acid, which causes the breakdown of the large pieces of protein that dogs eat. They also have an automatic regurgitation impulse, which allows incorrectly processed food to be brought back up and then reswallowed. Food is usually processed in the stomach within around three hours, although this depends upon the type of food. The capacity of the stomach will depend upon the size of the dog.
- Small intestine: the small intestine extracts the nutrients from the now-liquid food. It is where the main process of digestion takes place.
- Large intestine/colon: removes the last of the water from the food, and processes the waste before it is expelled through the rectum.
As a pet owner, you are probably already familiar with parts of the head area, as we often clean the face, wipe over their eyes, check their ears, and brush their teeth. The head is also an important area when grooming.
The key parts of the head are:
- Nose: dogs’ noses should be wet cold. The wetness is due to a combination of mucus secretion, licking, and moisture from the environment. Some breeds of dog have wetter noses than others.
- Muzzle: the muzzle can also be known as the foreface, and is the area from the eyes to the nose, and includes the upper and lower jaws and lips.
- The stop: this is the indentation between the muzzle and forehead that runs centrally and vertically between the eyes. It is not visible in all dog breeds.
- The forehead or braincase: similar to a human, it extends from the stop to the back of the skull.
- Occiput: the occipital bone is the protuberance at the back of the skull. The size varies dependent on the breed, and it was traditionally believed that the larger the projection, the better the sense of smell, although there is no evidence for this. As a result of this belief, scent hounds have been bred to have particularly prominent occiputs. The actual occipital bone reaches down the full length of the back of the skull and meets the neck.
- Ears: these may be pricked (upright), button (with a fold), or dropped (hanging down).
- Eyes: dogs’ eyes are usually brown, although some breeds may have blue eyes, for example border collies, or Siberian huskies.
- Whiskers: these are sensory and can detect subtle changes in air currents, and the speed and size of nearby objects. This can help them sense danger.
- Flews: the lips. In some breeds, for example bloodhounds, these are large and heavy.
- Cheeks: the sides of the muzzle.
Neck and shoulders
- Nape: the back of the neck, where it meets the skull.
- Throat: the front of the neck, below the jaw.
- Withers: the highest point of the shoulders, and the tallest part of the body.
Chest and trunk
- Chest: for dogs, this is not the front of the body. It is actually where the rib bones are, which are situated at the front of the trunk, and ends just above the shoulder blades.
- Back: technically, this runs from the shoulders to the end of the rib cage, but more colloquially, usually refers to the entire length of the spine, from the shoulders to the top of the tail.
- Loin: the correct term for the area between the end of the rib cage and the start of the pelvis.
- Abdomen: the soft, fleshy underneath of the dog.
- Flank: the side of the dog between the end of the chest and the back legs.
The front and hind legs of a dog are very different from each other.
Although known as legs, the sections of the front limbs of a dog are called by the same names as human arms. The upper part consists of the humerus bone, and is similar in structure to human upper arms. The lower leg meets the upper leg at the elbow, which is positioned just below chest height. This
section is lengthier and, as with a human, consists of the ulna and radius bones. The joint where the lower leg meets the paw is known as the wrist. While the elbow bends the same way as in a human, the wrist is limited to an up and down movement.
We use little of the same terminology for dogs’ back legs compared to human legs. The area above the knee is the upper thigh. The knee is also known as the stifle, and sits at the front of the leg, in line with the abdomen. The lower part of the leg is the lower thigh. What we would consider the ankle is called a hock. The hock is the sharply-angled joint at the back of the leg.
A dog’s paw is surprisingly complex, so we will break it down into sections.
- Bones: The bones found in a dog’s paws are similar to the bones that we have in the palms of our hands, and our feet excluding the toes.
- Pads: The paw is comprised of five pads on the bottom – the main pad and four toe pads – plus an additional small pad, just below the wrist. This pad is technically called a carpal pad, but more commonly known as a stopper pad. It provides additional traction when stopping, or going downhill.
Toes and claws
Although there are four toe pads, a dog has five toes. The last one, which is located on the inside of the leg, at wrist and ankle height, is very small. Each of the normal toes has a curved claw.
The claw on the small, inside toe, is known as a dew claw. Most breeds only have these on the front paws, although some breeds, such as Pyrenean Mountain dogs, also have them on their rear legs.
Dew claws can seem to have little function but they can be used to help grip bones for chewing. However, sometimes they are very loosely connected to the leg, and so may be removed to prevent them snagging on furniture or floors, and becoming painful.
Unlike humans, dog claws are part of the last toe bone, and so have blood flow to them. Unless care is taken, it is easy to catch the ‘quick’ when trimming them, causing them to bleed.
Tail and pelvis
The area around the pelvis is the croup, or rear, while the tail set is where the tail is attached to the dog. The tail can be set high or low.
2.2 Physical examinations at home
Detailed examinations carried out at home, can help identify illnesses or health conditions that need care or treatment.
There are a number of health problems that can develop and become serious within a relatively short space of time. The good news for owners is that monitoring your pet can help you detect signs of disease early on. This allows for timely intervention, which will minimise the potential for ongoing
issues. The earlier a problem is identified, the more treatable it is.
Animals that are handled regularly will be more comfortable with being examined. A physical examination once a month, checking for lumps, bumps, and other unusual features, is sufficient. Keep a record of dates of checks, and details of anything unusual. Should you need to consult a vet, this information will be invaluable.
2.3 Examining the head
To carry out an examination and make an assessment of your pet’s health is relatively simple, and gently placing your hands in a few key areas will provide a good insight.
Check the mouth by gently lifting the upper lip and checking the colour of the teeth and gums. Teeth should be white, while gums should be a healthy pink. Dogs can be prone to the buildup of tartar, which can lead to gingivitis. Gingivitis causes irritation to the gums and tissues, leading to gum disease if
untreated. There has been some correlation between organ damage and gingivitis, but this has not been studied enough to draw a definitive conclusion. If the gums have darkened in colour, or there is discolouration of the teeth, your vet may recommend professional teeth cleaning.
Just like humans, dogs have pulp inside their teeth. If teeth crack or break, this can be exposed, causing extreme pain to your dog. However, if a tooth has been worn this is unlikely to be causing them pain.
As possible in older dogs.Owners should also check for growths in the mouth. Mouth cancer is fairly common in dogs, with tumours typically found in the roof of the mouth, or around the upper teeth. Larger dogs aged between 6 and 22 months are most prone. In addition to lumps, other signs are excessive drooling or foaming, problems chewing, blood in the mouth, weight loss, and loose teeth.
Even a healthy dog’s nose may not be wet and cold all the time. Weather and humidity may cause it to be drier or warmer. However, noses that are dry and cracked, scabby, or red and sore, should be checked. Equally, any sort of unusual discharge should be investigated, as it may indicate a respiratory infection or a blockage.
Check for abnormal growths in the whites (sclera) of the eyes, by gently lifting the upper eyelids. The sclera should be white, although there may be a few visible blood vessels. If the vessels look enlarged, you may want to get them checked. Sclera that are discoloured could be a sign of metabolic
problems, while yellowishness can indicate liver malfunction.
Runny eyes are common, particularly in breeds like pugs or bulldogs, which have bulging eyes. If, however, the dog is rubbing its eyes, or has a greenish discharge around them, this could suggest such issues as blocked tear ducts, turnedin eyelids, or ingrowing eyelashes. This should be checked by
a vet, as it may require minor surgery. Other things to look for are discharge, redness, crustiness, or irritation. These could be indicators of allergies, or
foreign objects becoming lodged in the eye, or chronic conditions such as glaucoma.
Young dogs’ eyes should be bright and clear. In older dogs, eyes can become cloudy. Owners may wish to monitor how this progresses over time, and seek professional advice if they have concerns.
Some dogs are prone to excessive wax and dirt in the ears. This is because the length of the ear canal in a dog’s ears allows for the accumulation of debris and other irritants, which cannot easily be shaken out.
Breeds with pricked ears rarely have hidden problems. However, those with long, dropped, or particularly furry ears should be examined carefully on a regular basis, as the warm, damp environment encourages the growth of fungus, yeast and bacteria.
Crustiness, bleeding, scabs, sores, and bad odours should all be checked for. A dark, waxy discharge can indicate ear mites, while a foul smell accompanied by a pus-like fluid suggests a bacterial infection.
Where there are signs of excessive wax and dirt, but not infection, a vet-approved liquid cleaner, gently applied with cotton wool to the outer ear in a circular motion, is a safe and simple treatment. Owners should be careful not to push dirt towards the ear canal, as it can become more deeply lodged. After cleaning, your pet may shake its head. This also helps to loosen dirt.
Dogs with thick fur can develop mats behind the ear, which can affect freedom of movement, or even cause sores. The fur should be kept brushed, be clipped if necessary and matted hair removed. Some breeds, like Lhasa Apsos, have thick fur inside the ear. This should be trimmed regularly to help prevent infection.
2.4 Examining the body
Pet owners can gently feel along the body to identify sensitive areas, and check for lumps or changes in the musculature. This is easier on short, thin coated breeds. For dogs with thicker fur, owners may need to get their fingers into the fur to be able to feel any changes to the skin or tissues below.
The examination should encompass the neck, back, shoulders, abdomen and legs.
Lumps and bumps deserve special attention. The speed of growth does not indicate whether or not they are malignant, and all lumps should be checked by a vet. If you find a lump, make a note of the size and appearance, and when you last checked the area. This will give the vet an indication of how quickly it is growing.
When performing an examination, owners should be particularly careful to check areas such as under the leg joints, under the tail, behind the ears, and anywhere where small foreign objects can become lodged. Anything found should be removed.
2.5 About ticks
Sometimes, small bumps can be a sign of ticks or other biting insects.
Ticks can cause Lyme disease, which has symptoms including fever, appetite loss, lameness, joint swelling, and stiffness, and can lead to kidney failure, heart and neurological problems. Other diseases carried by ticks include ehrlichiosis and babesiosis, although the latter is very rare in the UK.
There are different species of ticks, with around twenty types indigenous to the UK. Some soft bodied, while others are hard bodied. In the UK, it is usually the hard bodied ticks that are found on pets or people.
Ticks are a member of the arachnid family, having eight legs, and are black or brown in colour. Sizes range from around 0.5mm up to 11mm, although the larger sizes are achieved only after they have managed to feed on a host for several days. Dogs that spend time outdoors, particularly if they are
exercised in leafy or woody areas, are more prone to picking up ticks. Ticks are more common in warmer weather, although even a few milder days in winter can cause them to become active.
As ticks have to burrow to attach themselves to a host, brushing after walks will help to dislodge them before they have time to attach. In addition, the head, face, paws, and joints should be checked for signs.
Tips for safe and effective tick removal
- Before removing a tick, have the following available:
- A clean pair of tweezers, preferably pointed OR a tick remover
- Pet-safe antiseptic cream
- Isopropyl alcohol in a container
- Someone to help if possible
Then follow this method:
- Put on the gloves as ticks can transfer diseases to human.
- Keep your pet calm. Many animals get nervous if they are poked or prodded, so this is where another person will come in useful.
- If using tweezers, grasp the tick as close to your dog’s skin as possible. If using a remover, slide the notch under the tick.
- Pull it out in a straight, steady action, ensuring that it is removed entirely. Anything left behind can lead to infection.
- Drop the tick into the container of isopropyl alcohol to kill it. Note the date, and keep the tick. If the dog displays signs of infection, your vet will want to know the date you found the tick, and may want to see it to help them identify the type of infection.
- Clean the wound with the antiseptic cream.
- Clean the tweezers or tick remover with the alcohol, and wash your hands carefully.
2.6 Examination of the abdomen
Make your pet lie on its back.
Gently run your hands over the belly region, from the ribs to the loin. Check for lumps, bumps, swelling, or distention (a particularly swollen stomach area). Distention can be caused by trapped gas or fluid.
If your pet experiences pain from being touched, it requires immediate medical attention. Pain may be caused by digestion, internal bleeding, tumours, or abscesses.
2.7 Examination of the paws
Animals often do not like having their paws touched, so examining them may be trickier than when looking at other areas.
Gently take each paw in turn, and examine the spaces between the toes and the area under the paw. Look for signs of soreness, particularly between the toes, as this area is warm and moist, and so can breed bacteria and fungus.
If you see your pet licking its paws excessively, this can be a sign that they are experiencing discomfort.
If you exercise your dog on concrete, the pads can become dry and cracked. Although the UK rarely experiences especially hot or cold weather, pet owners should take some precautions when it happens.
In hot weather, dog owners may prefer to exercise their pets before the sun gets too strong, and after sunset, particularly if you normally exercise them on tarmacked areas. This will help prevent their paws getting burned and causing them pain.
In winter, snow and ice can cause paws to become sore, both because of the cold and because of the products used to melt the ice. If you notice your dog limping after its walk, this can be a sign that it has been affected. In this case, wipe your dog’s paws with warm water.
Another problem in snowy conditions can be the formation of ice balls between their toes. To reduce the likelihood of this happening, keep the hair between the toes trimmed, particularly if the fur is thick. Short, frequent walks are better in cold conditions to prevent the risk of frostbite or hypothermia.
While you may not have heard of it, foxtail is a pointed, arrow-shaped weed whose seeds can penetrate the skin between the toes and cause abscesses. It can also get into ears or be inhaled.
If left untreated, embedded foxtail can become painful and cause infections; these infections can even be fatal. Loose seeds can be removed using tweezers but if one has become embedded, you should seek veterinary attention.
2.8 The problems associated with overgrown claws and how to trim them at home
Nail trimming is not only a cosmetic issue; long nails can cause pain, irritation, and even permanent deformities.
As discussed earlier in this module, a dog’s claws are an extension of the toe bone, so walking on hard surfaces can push them back into the nail bed. This creates pressure on the toe joints, or forces the toes to move sideways, which causes pain and can lead to musculoskeletal issues such as arthritis if left. Traditionally, dogs’ claws have been kept short by walking on hard surfaces, which wears them down, however for dogs walked on soft surfaces, this is not the case.
Long claws can cause other problems. Dogs, and other animals, use nerves in their feet to understand the terrain and environment. They also use their claws to judge depth
When climbing stairs.
Long claws can cause the dog to instinctively shift its posture forward to lean on its forelegs, to replicate the motion used when going uphill. However, because they are on a level surface, it will have to compensate by using its hind legs to prevent it falling forward. This forces the dog to bring its legs closer to the body.
Over time, these unnatural adjustments cause the joints to be overused and become painful. The hind legs are particularly affected, and this can lead to the dog being unable to climb stairs or jump into a car. The wrists of the front legs may also drop, which can make the dog look flat footed.
It is a good idea to trim claws on a regular basis but how often will depend on the dog’s activity levels. The more active a dog, particularly if this involves walking on hard surfaces, the less frequently they will need cutting. As with anything, it is best to start trimming the nails when the dog is still a puppy, as this familiarises them with the process, and reduces stress.
Some dogs will happily allow you to trim their claws, while others will be unsettled and skittish. Speaking calmly and reassuringly during the process will help to keep them still.
To cut the claws, you may wish to get your dog to lie on a table, to make it easier for you to reach. Whether on the floor or table, stand on the opposite side from the paw that you are about to trim, and reach over. A forearm rested on the neck will help to prevent the dog from lifting its head. If the dog won’t stay still, get it to lie on its side and lean across it with your upper body.
Owners should be careful to trim only the tips of the claws; as discussed above, claws have a blood supply as they are part of the toe, and cutting too far down will cause them to bleed from the ‘quick’.
For dogs with light coloured claws, it is easy to spot the pink-coloured section. Where dogs have dark nails, the owner will need to exercise caution, as it is not visible. You may need to trim the fur on your dog’s feet to be able to see the claws properly. Where nails are particularly long, the ends tend to be dry and cracked, making it easier to identify the living tissue.
There are two main types of nail clippers available: scissor and guillotine. Many people find the guillotine style easier to use, although if a nail is particularly long, scissors are the better option. The guillotine style encircles the nail, while the scissors should be used at a right angle. Owners should ensure that the blade portion faces them rather than the animal. Rather than make one big cut, trim the nail little by little. Hind paws are less sensitive than front paws, so it may be best to start there, although you may find that the claws of the rear paws need trimming less often than front ones.
Should you catch the quick, a styptic powder pencil should stop the blood flow within 3-4 minutes. Hold the pencil to the cut and rotate. Alternatively, dipping the claw into cornflour will also aid clotting. Dip the claw into the flour until it stops bleeding completely.
2.9 Limping and lameness in dogs
There are different reasons that dogs may limp, or display signs of lameness. Lameness is the inability to place weight on a painful limb, and reduced mobility. It may affect one leg or several, and may be worse at different times of the day, or following rest or exercise.
Lameness may be caused by a number of factors, including accident; bone, joint or muscle problems; or foreign objects becoming embedded. Problems are more likely, or can be exacerbated by obesity, or by excessive exercise and strenuous activity, and are also more prevalent in certain breeds of dog
Retriever breeds commonly suffer from hip dysplasia.
Common signs of lameness are:
- Reduced range of motion
- Loss of muscle mass or tone
- Abnormal posture, whether moving, sitting or lying
- Abnormal movements while walking, trotting, or climbing stairs
- Unusual trembling
- Clicking or other sounds during movement of joints
If a dog is holding its legs further forward than normal, it may be because it is experiencing pain in the hind legs, and is trying to reduce the pressure. Over time, you will notice that the claws on that paw will be longer than those on the other feet, as the reduced usage means that they are not getting the same wear.
If the lameness is in a front leg, the head and neck may drop forward as the affected limb is used, then go back to the normal position when the other legs are used. If it is in a back leg, the pelvis will drop, then rise back into position when the weight is removed. If the animal appears to be moving its weight forward to its front legs, with them appearing lower, it could be that both back legs are affected.
If seeking professional advice, owners should make a note of any patterns of lameness as this will aid the vet in making a diagnosis and prescribing treatment.
Time of day, or after rest or exercise.
Treatment by a vet may include bandage, splint, or cast. At home, owners may be instructed to restrict the amount of activity, or to ensure that it is not too strenuous. If the dog has a strain, sprain, or torn tendons or ligaments, the vet may recommend that the pet be kept in a crate or restricted space to prevent further damage and increase the likelihood of healing without surgery.
2.10 Examination around the tail
Finally, it is important to check the rear area of the dog, especially under the tail and around the loin region.
In this area, look for redness, swelling, or skin irritation, particularly if you have noticed your dog licking itself more than usual. If your dog has been dragging itself across the floor on its bottom, this is a common sign that it needs its anal gland emptying, which should be done by a vet. If you see small, whitish, grain-like items around the anus, wipe them away with a paper towel while wearing latex gloves, and carefully dispose of them. These may be a sign of tapeworm, and you should request a worming medication from your vet.