A general understanding of the anatomy of a dog’s body is very important for any dog ​​owner: a kennel owner, a breeder or a simple fancier. Anatomy studies the external and internal structure of a dog's body. The internal structure consists of the skeletal system and internal organs. It is this knowledge, combined with physiology, that can help, for example, provide timely first aid to a pet or correctly assess a dog’s exterior.

Anatomical parts of a dog's body

Features of the location of various parts of the body, physique and general appearance of the dog in accordance with their breed characteristics are called exterior. To evaluate the exterior Anatomically, there are several parts of a dog’s body:

• Head. The skull and muzzle, eyes, ears, and dental system are assessed.
• Torso. Along the top line look at the withers, back, loin, croup and tail. The chest and abdomen are assessed along the bottom line.
• Limbs. Presented front and rear.

Knowledge of exterior features is especially necessary for owners of purebred dogs. It helps control, preserve and develop dog breeds.

Skeletal system

Studying anatomy is necessary start by considering the skeletal system. The skeleton is the bony basis of a dog's body. The development and productivity of the dog’s body as a whole depends on its condition. The skeletal system, together with joints, ligaments, muscles and tendons, makes up the musculoskeletal system. There are axial and peripheral sections of the skeletal system.

Axial section of the system

The structure of the axial skeleton includes:

• Scull.
• Spinal column.
• Chest with ribs.

Skulls are either dolichocephalic (long) or brachycephalic (short). The first are typical for the breeds of shepherd dogs, Dobermans, collies, the second type of skull is for Pekingese, pugs, and bulldogs. Dog skull has a cranial and facial (muzzle) part. The bones of the skull, with the exception of the lower jaw, are fixedly connected. The mobility of the lower jaw is due to the need to grasp, hold and chew food. The dental system actively participates in this process. Adult dogs have 42 teeth, puppies have 28. There are incisors, canines, premolars and molars. The puppies are missing molars and one premolar.

Depending on breed characteristics When the front teeth (incisors) occlude, they form a defined bite. The most preferred and most often mandatory for most breeds is the scissor cut, in which the upper incisors fit tightly behind the lower ones. In a straight bite, which is acceptable for some breed groups, the surfaces of the incisors are brought together by the cutting edges. Underbite is manifested by a strong protrusion of the upper jaw in front of the lower jaw, so that a large gap is formed between them. Underbite is characterized by protrusion of the lower jaw, causing the lower incisors to protrude in front of the upper ones and is a characteristic feature of breeds with a short muzzle.

The spinal column of a dog consists of seven cervical, thirteen thoracic, seven lumbar, three sacral and several caudal vertebrae.

The cervical region consists of seven cervical vertebrae, which begin with the first, the atlas, and the second, the epistrophea. The skull is attached to them and they allow the dog's head to be movable in different directions.

The thoracic region is represented by thirteen vertebrae, to which curved ribs of varying lengths are attached. The first four pairs of ribs close into the costal arch, the remaining nine pairs are shortened towards the lumbar region and bend freely. The ribs serve as protection for the dog’s internal organs and are involved in the breathing process.

The lumbar region consists of seven segments. The loin should not be long - this is considered a big drawback. Ideally, it is desirable to be short, convex and wide, reliably connecting the thoracic and pelvic spine and capable of acting as a spring. A long loin greatly affects the dog’s movements, the gait becomes slack, and the rear begins to wag.

Typically, dogs have 20–23 caudal vertebrae. There are also smaller numbers. To meet the standard, in some breeds the tail vertebrae are cut off (cropped), leaving several segments.

Peripheral skeletal system

The section is represented by the front and hind limbs of the dog.

The forelimb consists of a shoulder blade, preferably set obliquely, to which the humerus is attached through the glenohumeral joint. The shoulder is connected through the elbow joint to the bones of the forearm, consisting of two bones - the ulna and the radius. For most breeds, it is highly desirable that the lowest point of the costal arch reaches or is below the elbow joint . Chest depth- one of the important parameters of the exterior. A fairly deep chest, with a moderate width, creates the basis for good development of the internal thoracic organs: heart, lungs, blood vessels.

The wrist joint consists of seven bones that connects the bones of the forearm to the five bones of the metacarpus. The forelimb ends with fingers, each of them is equipped at the end with a hard claw that cannot retract. Four fingers have three phalanges, and one has only two.

The forelimb is attached to the vertebral skeleton by very strong shoulder muscles. The protrusion of the obliquely set shoulder blade, rising above the thoracic vertebrae, creates a prominent withers. Measurements from the highest point the withers to the ground of a calmly standing dog is a very important exterior parameter and is called “height at the withers” for evaluation. Depending on the accepted breed standard, the height at the withers has a different meaning. The fluctuation in height at the withers in various breeds sometimes simply amazes the imagination with the wonders of the selection work of breeders and breeders. So great is the difference in height between a miniature lap dog and the giants of the canine world, Great Danes and wolfhounds - from 6.5 cm to 111.8 cm in height at the withers.

The hind limb girdle begins at the hip joint, which articulates the entire hind limb with the pelvic bone of the dog's spine. The hind limb consists of the femur, which through the knee joint is connected to two bones of the lower leg: the tibia and tibia.

The usually unnoticeable stifle joint serves an important function in the dog's musculoskeletal system. . Straightening up, he gives a start to the push y, which produces the hind limb. This thrust ends with extension of the hock joint (tarsus), which connects the shin bones to the metatarsus. The large heel bone is clearly visible on the hock joint. Four metacarpal bones, occasionally five, transform into three phalangeal fingers, which end in strong claws.

Puppies are sometimes born with a fifth toe on their hind limb. These dewclaws are often injured, so they are removed, as prescribed by breed standards. In rare breeds, dewclaws are left behind. Among the Beaucerons(French Shepherd) they must be double, their absence will lead to the disqualification of the dog. In the Tibetan Mastiff and the Italian Pointer, the dewclaws are left at the request of the breeder or owner.

Internal structure of a dog's body

The internal organ system consists of the digestive, respiratory, excretory and reproductive systems.

Digestive

Its main purpose is in consumption, promotion, digestion, absorption of food and water. Starting in the mouth with the teeth, it passes into the esophagus, which is adjacent to the stomach. In the stomach, food and water are mixed and, with the help of released hydrochloric acid, are broken down into nutrients (digestion process). Moving further, the food bolus enters the duodenum of the intestine.

The intestine is the main organ for further digestion and absorption of broken down particles - nutrients. The pancreatic secretions and bile, the pancreas and the liver and gall bladder, respectively, open their ducts into it and secrete the substances necessary for digestion. The intestinal section is very long, its length is from two and a half to seven meters. The intestine is divided into the small and large intestine, which ends in the anus.

Respiratory

The respiratory system is designed for gas exchange in the lungs. Oxygen enters the blood from the air, and carbon dioxide is removed back. By contracting and relaxing, the rib muscles cause the lungs to contract to remove carbon dioxide and inflate to suck in oxygen. The respiratory system consists of from the nasal and oral cavities, larynx, trachea and lungs.

excretory

The system is represented by two kidneys with a ureter, bladder and urethra. The end products of metabolism from the blood in the kidneys pass through filtration into urine, which is collected in the bladder through the ureters and periodically removed from the body through the urethra.

Reproductive system

The organs of the reproductive system serve for procreation. Their structure is different in different sexes. In males, it includes the testes located in the scrotum, the vas deferens, the penis, covered by the prepuce . Bitches have a reproductive organ system has an internal location in the body and consists of the ovaries, fallopian tubes, uterus, vagina and external genitalia.

Management of the entire body as a whole

To control all systems of the body, the nervous, circulatory, immune, lymphatic, hormonal, skin and sensory systems are used.

Nervous

The system is divided into central and vegetative. It consists of nerve fibers. Thanks to its high development, dogs have enhanced senses such as smell, vision and hearing. The central nervous system, together with the cerebral cortex, through congenital and acquired reflexes during life, regulates all systems of the dog’s body.

Blood

The cardiovascular system includes the heart and blood vessels: arterial, coming from the heart, and venous, coming to this organ. The main arterial vessel is called the aorta. The cardiovascular system designed to supply all organs and cells of the body with oxygen and nutrients and remove metabolic end products. The location of the heart is the chest. It is located on the left side of it.

Sense organs and skin

External and internal influences are perceived and analyzed by the senses. A dog has five senses: visual, auditory, olfactory, gustatory and tactile. The optic eye consists of the eye with the pupil, eye muscles and nerves.

Hearing analyzer includes the ear, the structure of which is such that it not only perceives vibrations of sound waves, turning them into sound, but also has the function of correct orientation in space - balance. The sense of smell in dogs is very developed, its acuteness depends on individual characteristics and training. Taste buds are located on the dog's tongue and serve to analyze the composition and quality of substances that enter the mouth.

The cutaneous organ of touch represents primarily a barrier between the external environment and the internal system of the dog’s body. The tactile function protects the organs from adverse effects. Skin composition:

• Subcutaneous tissue.
• Epidermis.
• Wool is a derivative of leather.

Knowledge of the anatomy of the canine body It allows us to better understand the reasons that motivate our pets to behave in one way or another.

Surely every dog ​​breeder or simply a fan of man’s four-legged friends will be interested in learning about what the “internal structure” of dogs is like? What do we and our pets have in common, and how are we strikingly different? Therefore, we suggest making a detailed excursion into the world of canine anatomy right now!

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Skeletal structure

Naturally, studying the anatomy of any animal begins with studying the structure of its skeleton. The skeleton of a dog is the foundation, the frame that holds all the organs and muscles of the dog inside. Let's look at all the “components” of a dog’s skeleton one by one.

Scull

The skull of dogs is usually divided into facial and brain parts. Both of these parts consist of paired and unpaired bones (discussed in the table below).

It is easy to calculate that a dog’s skull will consist of 27 bones, which are securely connected to each other by connective cartilage tissue. As the dog gets older, this tissue ossifies. In this case, the lower jaw is attached to the skull with the help of a strong movable joint, which allows the dog to chew food.

Note that the shape of the skull of dogs can vary greatly. In the process of selection, people contributed to the fact that some breeds were recognizable precisely due to the original structure of the skull.

Thus, according to the shape of the skull, dogs are divided into long-faced, short-headed and dogs with normal head length. Moreover, it is the facial part of the skull that will make the biggest differences. The general name for all breeds with a shortened facial part of the skull is brachycephalic.

Vivid examples of the brachycephalic structure of the skull are Pekingese, Bulldogs, Pugs, Boxers, and Shar-Peis. These dogs have a wide parietal part of the skull, a greatly shortened and flattened facial part and a protruding jaw. This special structure is the result of many years of selective breeding work, when individuals with the desired trait, in this case a flattened muzzle, were deliberately selected. However, such an unusual symptom turned out to be associated with significant health problems.

After all, the disproportionately short muzzle caused degenerative changes in the structure of the dog’s respiratory tract. Because of this, all of the above breeds are prone to tracheal collapse, pulmonary hypertension and excessive tear production. Surely everyone has noticed that outwardly cute Pekingese or Pugs often walk around “tear-stained”, and every breath they take is accompanied by wheezing or grunting. To describe all the inconveniences that a brachycephalic dog experiences, there is even a special term - brachycephalic syndrome.

However, let's return to the structure of the skull and say a few more words about the teeth and bite of the dog. Thus, the dental system of dogs requires the presence of canines, incisors, molars and premolars. An adult dog should have 42 teeth, and the baby jaw consists of 28 teeth. The bite of dogs can be different, it depends on the breed and the standard prescribed by this breed.

There are the following types of dog bites:

1. Scissor-shaped, when the upper incisors in a closed form cover the lower ones. In this case, the lower incisors are closely adjacent to the upper ones.
2. Pincer-shaped, the incisors of both jaws adjoin each other with a cutting surface.
3. Undershot, the lower jaw is inferior in length to the upper, so there is free space between the dog’s incisors.
4. An undershot jaw, the lower jaw protrudes forward, is also called a “bulldog” jaw.

Torso

The dog’s body itself will consist of the spinal column - the axis of the body and the ribs that are attached to it and together make up the dog’s skeleton (in the picture below you can see the dog’s skeleton).

The dog's spine, in turn, consists of the following sections:

• cervical - formed by seven vertebrae, the first two are more mobile and are called atlas and epistropheus, like in cats;
• thoracic - made up of 13 vertebrae;
• The lumbar region, like the cervical region, consists of 7 vertebrae;
• The spinal column is completed by the sacral section, the single sacral bone of which is made up of 3 fused vertebrae.

The tail consists of 20-23 movable vertebrae. The chest is represented by 13 pairs of ribs, 9 of which are true and attached to the sternum, and 4 false form the costal arch. Dogs' ribs provide reliable protection for the heart and lungs and have different curves depending on the breed. The lumbar vertebrae are large and have many spurs, thanks to which the muscles and tendons that hold the abdominal organs are securely attached to them. The sacral vertebrae fuse into a single strong bone, which serves as a transition between the loin and the tail.

The first five vertebrae of the caudal region are the most developed and mobile. According to the standard of some breeds, the caudal vertebrae are docked in the quantity prescribed by this standard.

Limbs

The limbs of dogs have a rather complex structure. The forelimbs are a continuation of the obliquely set scapula, which passes into the humerus with the help of the glenohumeral joint. Next comes the forearm, where the radius and ulna bones are connected by the elbow joint. This is followed by the carpal joint, which consists of 7 bones connected to the 5 bones of the metacarpus.

The metacarpus consists of 5 fingers, 4 of them have three phalanges, and 1 has two. All fingers are “equipped” with claws, which, compared to cats, are not retractable and consist of strong keratinized tissue.

The front legs are attached to the spine by strong shoulder muscles. Due to the fact that the upper parts of the shoulder blades protrude beyond the thoracic vertebrae in dogs, a withers is formed - an indicator of the dog’s height. The hind limbs are represented by the femur and tibia, where the connecting elements are the hip and knee joints.

The lower leg, which consists of the tibia and fibula, is attached to the tarsus using the hock joint. The tarsus, in turn, passes into the metatarsus and ends in 4 fingers with three phalanges. A detailed explanation of the structure of the dog's foot is available in the video below.

Internal organs

Naturally, familiarity with the anatomy of a dog cannot be limited only to the skeleton and musculoskeletal system. If we already have some idea about the skeleton of a dog, let's talk about its internal organs and systems.

Digestive system

The digestive system of dogs is very similar to the digestive system of other mammals, including you and me. It begins with the oral cavity, which is equipped with strong and sharp teeth. Our pets are predatory animals, and therefore their jaws are adapted to eating large pieces of meat. Moreover, food is not always crushed in the mouth; dogs often swallow fairly large pieces whole. Our pets begin to actively produce saliva from the mere smell of food and its appearance, and the enzyme composition of saliva is slightly different; each breed has its own.

The food then moves through the esophagus and reaches the stomach. The main “digestion” occurs in this muscular organ. Gastric juice and special enzymes, under the influence of peristaltic processes, transform food into a homogeneous mass called chyme. At the same time, the stomach valves should not allow food to return back into the esophagus or enter the small intestine prematurely. At least this is how a healthy dog's digestion should proceed.

Well, the small intestine, which is next in line, closely “interacts” with the pancreas, duodenum and liver. Pancreatic and gallbladder enzymes continue to act on the chyme. And the walls of the small intestine actively absorb useful substances from it in order to “transmit” them into the blood. At the same time, the small intestine is quite long, and its absorption area is impressive - depending on the breed, it can be equal to the area of ​​a room!

The digested food then moves into the large intestine. By this point, all the beneficial substances have already been taken from it, only water and coarse fiber can remain. Feces will be formed from the remains of waste food, water, some bacteria and inorganic substances. Defecation occurs under the control of the central nervous system; in case of nervous disorders or old age, bowel movements may be uncontrollable.

Respiratory system

The dog's respiratory system performs a vital function: thanks to it, all cells of the body receive the required dose of oxygen, and waste carbon dioxide is removed. The respiratory system of all mammals, and dogs are no exception, is usually divided into upper and lower sections. The upper section consists of the nasal cavity, nasopharynx, trachea and larynx. The movement of air begins through the nasal passages - nostrils, the shape and size of which depend on the breed of the dog. In the nasopharynx, the inhaled air is warmed, and thanks to the nasal glands, the air is “filtered” from dirt and dust.

Next, the air moves through the larynx, a cartilaginous organ that is held by the hyoid bone and is equipped with vocal cords, that is, it is responsible for sound production. Next comes the trachea, also a cartilaginous organ, closed by the tracheal muscle. The lower part of the respiratory system is represented by the lungs and bronchi. The lungs, in turn, consist of 7 lobes and are heavily dotted with blood vessels to enrich them with oxygen. The lungs are an organ that can significantly change its volume: when you inhale, they increase many times over, and when you exhale, they seem to “deflate”.

This elasticity is possible thanks to the rhythmic contractions of the diaphragm and intercostal muscles. During inhalation, old air is “replaced” with oxygen-saturated new air in the alveoli of the lungs. The respiratory rate of dogs should be in the range of 10-30 breaths per minute, it depends on the breed and physical condition of the pet. Small dogs breathe more frequently than large dogs. The breathing rate can change greatly in case of fear, heat and physical exertion.

Circulatory system

Naturally, the main organ of the circulatory system is the heart. Through arteries, blood is distributed to all other organs, and through veins it returns to the heart. The dog's heart is a strong muscular hollow organ that is located between the 3rd and 6th ribs in front of the diaphragm.

The heart has four chambers and is divided into two parts: right and left. Both parts of the heart are in turn divided into the atrium and ventricle. In the left side, arterial blood circulates, entering there through the pulmonary veins, in the right - venous blood, which enters the heart from the vena cava. From the left side, oxygenated arterial blood flows into the aorta.

The heart provides a continuous flow of blood in the body, it moves from the atria to the ventricles and from there enters the arterial vessels.

In this case, the walls of the heart consist of the following membranes: the inner membrane - the endocardium, the outer membrane - the epicardium and the cardiac muscle of the myocardium. In addition, the heart has a valve apparatus, which is designed to “monitor” the direction of blood flow and to ensure that arterial and venous blood does not mix. The size of the heart and the frequency of its contractions greatly depend on the breed of the dog, its gender and age, and environmental factors.

The first indicator of a dog's heart function is the measurement of the pulse, which normally ranges from 70-120 beats per minute. Young individuals are characterized by more frequent contractions of the heart muscle. The complex device has a system of capillaries and blood vessels of the dog, which literally “penetrates” the entire body of the animal and all its organs. For 1 sq. mm of tissue there are more than 2500 capillaries. And the total volume of blood in a dog’s body is 6-13% of body weight.

Excretory system

The excretory system of our little brothers cannot function without internal organs such as kidneys (available in duplicate). They communicate with the bladder through the ureters and end in the urethra. The purpose of the excretory system is the formation, accumulation and removal of urine from the animal’s body. Through urine, the body is freed from metabolic products; any violations in this process are fraught with serious health problems, including death.

To filter blood, the kidneys are equipped with nephrons, each of the nephrons is enveloped in a network of tiny blood vessels. As an animal ages, nephrons will break down and be replaced by scar tissue, making kidney problems common in older animals.

Reproductive system

The reproductive system is closely connected with the excretory system. Anatomically, in males, the urinary canal is also the vas deferens; in addition, for reproduction, males need testes and an external genital organ. In this case, in a newborn male dog, the testicles are located in the abdominal cavity, but by two months they will descend and take their place in the scrotum. It is there that the sperm will subsequently “mature”. In addition to the testes, males have a prostate, a sex gland that maintains the viability of sperm.

The male penis, consisting of a head, body and root, is covered by a preputial sac; at the moment of arousal, the sexual organ comes out of the sac and this is called an erection. Moreover, the hardness of the penis is achieved not only due to the cavernous bodies, but also due to the bone located at the base of the organ. Puberty in males, as well as in females, occurs at 6-11 months; small dogs “mature” faster. But males are allowed to mate at 15-16 months, and females at 1.5-2 years; by this age, dogs have completely completed puberty and will definitely give birth to healthy offspring.

The genital organs of females are the uterus; by the way, the uterus of dogs has “horns” to which the ovaries, fallopian tubes and vagina are “attached”. The egg of a female dog, like that of a human, matures in the ovaries. This process is quite complex and occurs under the constant “control” of hormones. As estrus approaches, the follicles containing the egg enlarge, and when estrus occurs, the follicle bursts, clearing the way for the egg. The egg matures in the fallopian tubes for another three days, while the fluid from the ruptured follicle produces a hormone that prepares the female’s body for pregnancy.

Bitches come into estrus twice a year, but dogs of northern breeds have estrus once a year and it lasts about 28 days. The optimal time for mating is 9-14 days of estrus. If a female mated with two males, then her litter may contain puppies from both males. Therefore, breeding of purebred dogs always occurs under close control from the owner. And one more nuance: dog embryos do not develop in the uterine cavity, but in the horns - tube-shaped processes on both sides of the main reproductive organ.

Nervous system

The nervous system of dogs is represented by central and peripheral sections. The central nervous system consists of the brain and the spinal cord adjacent to it, and the peripheral nervous system consists of many nerve endings and fibers that penetrate all the organs and tissues of the animal. Bundles of nerve fibers make up nerve trunks, which are more simply called nerves. All nerves are divided into afferent and efferent. The former transmit “information” from the organs to the control center - the brain, and the latter, on the contrary, transmit impulses arising in the brain to the organs and tissues of the dog.

The building block of the dog’s entire nervous system is the nerve cell, which necessarily has processes. The transmission of nerve impulses occurs through the contact of nerve cell processes and with the help of mediators. Mediators are substances that transmit impulses. Information is transmitted through nerve cells and fibers as if by telegraph, and the transmission speed is about 60 m/s.

Sense organs

Dogs' sense organs are extremely developed. This predator is able to hear and smell much better than you and I. Therefore, we propose to talk about the dog’s senses in more detail, because without them the dog would not be the same as we are used to seeing it.

Structure of the eye

The eye of our four-legged friend consists of three membranes: fibrous, vascular and retinal. In principle, the structure of a dog's eye is anatomically very similar to our organ of vision. The principle of perception of visual information in a dog is no different from the principle of perception of all other mammals. A beam of light passes through the cornea and hits the lens, which focuses the light onto the retina, on which the light-perceiving elements are located. The light-perceiving elements in dogs, just like in us, are rods and cones.

The human eye is equipped with a so-called yellow spot - the place of the highest concentration of light-receiving elements; dogs do not have a yellow spot, so their vision is worse than that of humans. However, a dog can perceive information better in different lighting conditions, so our friends navigate in the dark much better than us.

Ear structure

Our four-legged pets perceive a lot of information through hearing, which they have much more acutely than you and I. The dog's auditory analyzer begins with the outer ear, moves to the middle ear and ends with the inner ear. The outer ear begins with the auricle, which is necessary for capturing sounds and directing them to the deep parts of the auditory organ. The auricle is a cartilaginous organ to which muscles are attached, allowing it to be rotated to improve focusing on the source of sound. The external auditory canal follows the auricle and is divided into horizontal and vertical parts.

Essentially, the ear canal is a skin tube through which sound travels to the eardrum. The skin of the auditory canal contains numerous glands, and hair often grows profusely in the auditory canal of dogs. Next comes the eardrum - the thinnest membrane, it serves to separate the outer and middle ear and capture vibrations of sound waves. The middle ear can be characterized as a bony cavity, which is the “receptacle” of the auditory ossicles (hammer, stapes and incus) and the inner ear. The auditory ossicles are attached to the inside of the eardrum and greatly amplify sound vibrations, transmitting them to the structures of the inner ear.

The inner ear is a container for auditory receptors and an organ of balance - the vestibular apparatus. It is in the inner ear that sound vibrations are analyzed and information is generated for transmission to the brain.

Structure of the nose

A dog’s nose is a hypersensitive organ; in principle, we can say that our four-legged friends live in a world of smells. Animals associate everything that surrounds them with some kind of smell, including you and me. A dog's nose is equipped with 125 million olfactory receptors, while our humble nose has only 5 million. The mucus that covers the inner surface of both our and the dog's nose, in dogs extends beyond the olfactory organ and also covers its outer part. This is why our pets' noses are so wet.

Smell recognition in dogs begins with the nostrils, and their side cutouts play an important role here. More than half of the inhaled air passes through them. In general, the airways begin from the external nose and the nasal cavity, which is divided into the lower, middle and upper passages. The upper part of the nasal cavity is the home of the olfactory receptors. And the lower part leads the inhaled air to the nasopharynx.

Interestingly, the outer pigmented part of a dog's nose is called the nasal planum. Each dog's mirror has its own unique pattern, thanks to which, if necessary, one dog can be distinguished from another. In addition, dogs' olfactory organ is able to detect odors from a distance and differentiate them - a property available only to some people. It is thanks to this property that dogs greatly help a person for whom the world of smells is only partially accessible.

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Video “How do dogs see the world with their nose?”

We have already mentioned how much information our four-legged friends receive through their noses. But this video, which completes your introduction to canine anatomy, will tell you something more interesting about the hypersensitive dog nose!

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Dogs are mammals, therefore, their skeleton is typical of mammals and consists of the same sections.

Mammals have a larger skull than, for example, reptiles.

Mammals are characterized by the presence 7 cervical vertebrae. Both giraffes, which have a very long neck, and whales, which have no neck at all, have the same number of cervical vertebrae. The thoracic vertebrae (usually 12-15 of them) together with the ribs and sternum form the chest.

The lumbar spine is formed by massive, movably articulated vertebrae that provide flexion and extension in this section of the spine. This way the torso can bend and unbend. The number of lumbar vertebrae in different species of mammals can vary from 2 to 9; in a dog there are 6. The sacral spine consists of 3-4 vertebrae, which are connected to the pelvic bones.

The number of vertebrae in the caudal region in dogs can range from 3 to several dozen, which determines the length of the tail.

The girdle of the forelimbs of mammals consists of two shoulder blades, crow bones fused with them, and a pair of underdeveloped clavicles.

The girdle of the hind limbs - the pelvis - in a dog is formed by 3 pairs of pelvic bones. Most mammals, including dogs, have especially developed muscles in the back and limbs.

The dog's mouth, like that of other mammals, contains its tongue and teeth. The tongue is used to determine the taste of food: its surface is covered with numerous papillae, which contain the endings of the taste nerves. The movable tongue moves food around the mouth, which helps wet it with saliva secreted by the salivary glands. Mammalian teeth have roots with which they are strengthened in the sockets of the jaws. Each tooth consists of dentin and is covered on the outside with durable enamel. In mammals, teeth have different structures associated with a specific purpose. In the front of the dog's jaws there are incisors, on both sides of which there are fangs. In the depths of the mouth are the molars.

The muscles of the lower jaw are also very developed, thanks to which the dog is able to firmly hold prey

Skeleton of a dog: 1 – upper jaw; 2 – lower jaw; 3 – skull; 4 – parietal bone; 5 – occipital protuberance; 6 – cervical vertebrae; 7 – thoracic vertebrae; 8 – lumbar vertebrae; 9 – caudal vertebrae; 10 – shoulder blades; 11 – humerus; 12 – bones of the forearm; 13 – carpal bones; 14 – metacarpus; 15 – phalanges of fingers; 16 – ribs; 17 – costal cartilages; 18 – sternum; 19 – pelvic bone; 20 – hip joint; 21 – femur; 22 – knee joint; 23 – tibia; 24 – fibula; 25 – calcaneus; 26 – hock joint; 27 – tarsus; 28 – metatarsus; 29 – fingers

Puppies first develop baby teeth, which later fall out and are replaced by permanent teeth.

All a dog's teeth have a purpose. It uses its molars to tear large pieces of meat.

The outer molars have blunt tips that help chew plant foods. Incisors are designed to separate meat from bones.

The dog's stomach, like that of most mammals, is single-chamber; the intestine consists of the small, large and rectum. In the intestines, food is digested under the influence of the secretions of the digestive glands of the intestines, as well as the juices of the liver and pancreas.

In a dog, like in other mammals, the chest cavity is separated from the abdominal muscular septum - the diaphragm, which protrudes into the chest cavity and is adjacent to the lungs. When the intercostal muscles and diaphragm contract, the volume of the chest increases, the ribs move forward and to the sides, and the diaphragm becomes flat from convex. At this moment, the force of atmospheric pressure forces air into the lungs - inhalation occurs. When the ribs descend, the chest narrows and air is pushed out of the lungs - exhalation occurs.

Internal organs of the dog: 1 – nasal cavity; 2 – oral cavity; 3 – trachea; 4 – esophagus; 5 – lungs; 6 – heart; 7 – liver; 8 – spleen; 9 – kidneys; 10 – small intestine; 11 – large intestine; 12 – anus; 13 – anal glands; 14 – bladder; 15, 16 – genitals; 16 – brain; 17 – cerebellum; 18 – spinal cord

The dog's heart has four chambers and consists of 2 atria and 2 ventricles. The movement of blood is carried out in 2 circles of blood circulation: large and small.

Urine is excreted through the kidneys, a paired organ located in the abdominal cavity on the sides of the lumbar vertebrae. The resulting urine flows through 2 ureters into the bladder, and from there it is periodically discharged through the urethra.

Metabolism in mammals, due to the high development of the respiratory and circulatory systems, occurs at high speed. The body temperature of mammals is constant.

The brain of dogs, like other mammals, consists of 2 hemispheres. The cerebral hemispheres have a layer of nerve cells that form the cerebral cortex.

In many mammals, including dogs, the cerebral cortex is so enlarged that it forms folds-gyri, and the more convolutions, the better developed the cerebral cortex and the more nerve cells it contains. The cerebellum is well developed and, like the cerebral hemispheres, has many convolutions. This part of the brain coordinates the complex movements of mammals.

The normal body temperature of a dog is 37–38 °C; puppies under 6 months of age have an average temperature of 0.5 °C higher than that of adult dogs.

Dogs have 5 senses: smell, hearing, vision, touch and taste, but they are not equally developed.

Dogs, like most land mammals, have a good sense of smell, which helps them track prey or detect another dog by scent, even at a considerable distance. The hearing of most dogs is also well developed, this is facilitated by movable ears that capture sound.

The organs of touch in dogs are special long and stiff hairs, the so-called vibrissae, most of which are located near the nose and eyes.

By bringing their heads closer to any object, mammals simultaneously sniff, examine and touch it. The behavior of dogs, along with complex instincts, is largely determined by higher nervous activity based on conditioned reflexes.

Immediately after birth, the puppy’s social circle is limited to its mother and other puppies, among whom it receives its first skills of communicating with the outside world. As puppies grow older, their personal experience with their environment continually increases.

Changes in the environment cause dogs to constantly develop new conditioned reflexes, and those that are not reinforced by stimuli disappear. This ability allows dogs to adapt to changing environmental conditions.

Puppy games (wrestling, chasing, jumping, running) serve as good training and contribute to the development of individual attack and defense techniques.

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For any dog ​​owner, knowing at least the basics of your pet's anatomy will be useful. This will help you evaluate its appearance, understand the nuances of behavior and the causes of predisposition to certain diseases, and, if necessary, provide first aid to your pet. From this material you can glean basic information about the dog’s skeletal and muscular system, its internal organs and sensory organs.

Like any vertebrate, the dog has an internal skeleton. Let us remember that this term refers to a set of bones that are connected by bone or cartilage tissue. The bones of the skeleton play both a protective role and are the basis for soft tissues (muscles, for example).

Did you know? Like human fingerprints, each dog's nose has a unique pattern, which is why noseprints are used to identify these pets.

This part of the skeleton is a load-bearing element consisting of vertebral discs, which are connected to each other by cartilaginous formations called intervertebral discs. The connecting discs, on the one hand, provide mobility to the animal’s vertebra, and on the other, act as shock absorbers. The spinal column is conventionally divided into the following sections:

• cervical spine with seven vertebrae, with the two upper vertebrae characterized by increased mobility;
• the thoracic region, consisting of thirteen vertebrae, which serve as the basis for attaching the ribs;
• lumbar region, containing the seven most massive vertebrae;
• the sacrum, also called the sacrum, consists of three fused vertebrae;
• the tail contains up to 23 movable vertebrae, decreasing towards the tip of the tail.

There are three types of skulls in dogs:

Important! The structure of the skull of short-headed dogs (flat muzzle and wide crown) is the cause of respiratory problems in these breeds. Outwardly, this manifests itself as hoarse breathing and increased salivation.

The skull itself is divided into a fixed axial part and a movable part, which includes the lower jaw and hyoid bone. In addition, a dog’s skull is divided into two sections: the brain and the facial. The medulla contains 3 paired bones and 5 unpaired bones, namely:

Dog skull: 1 – incisive bone; 2 – nasal bone; 3 – maxillary bone; 4 – lacrimal bone; 5 – zygomatic bone; 6 – frontal bone; 7 – parietal bone; 8 – temporal bone; 9 – occipital bone; 10 – lower jaw

• frontal bone - paired, both bones form the front part of the skull, partially form the eye sockets, temples, nose;
• parietal bone - paired, both bones are in contact with the frontal bones, forming the parietal part of the skull;
• temporal - paired, both bones partially form the cheekbones, contain the hearing organs, mate with the lower jaw, the masticatory muscles are attached to it;
• interparietal - unpaired, located between the occipital bone and the parietal bones;
• occipital - unpaired, forms the back of the head;
• sphenoid - unpaired, connects to the occipital bone;
• pterygoid - unpaired, takes part in the formation of the nasal cavity;
• ethmoidal - partially forms the brain cavity.

In the facial part of the skull there are 8 paired and 4 unpaired bones:

• the nasal bone is paired, the nasal concha is attached to these bones;
• the maxillary bone is paired, these bones partially form the nasal cavity;
• mandibular - steam room;
• incisive - paired, these bones form part of the palate;
• palatine - steam room, partially forms the palate;
• vomer - unpaired, divides the choanae (internal openings of the nasal cavity);
• lacrimal - steam room, forms part of the orbit with the lacrimal opening;
• zygomatic - steam room, partially forms the eye sockets and cheekbones;
• The superior and inferior turbinates are unpaired and form the base of the nasal concha.

In addition to the skull bones, it is important to have an understanding of the characteristics of the dog's teeth. An adult dog has 42 teeth, puppies have 28 teeth. Different breeds may have different bites. There are several types of bite:

• scissor-shaped (aka normal) - the upper and lower incisors are tightly connected, with the lower ones slightly extending beyond the upper ones;
• pincer-shaped - the upper and lower incisors are closed edge to edge;
• undershot - the lower incisors noticeably do not reach the line of the upper ones;
• undershot (or bulldog) - due to the shortened muzzle, the lower jaw protrudes forward in relation to the upper jaw.

Ribs

The dog has thirteen pairs of ribs. These bones are curved in an arc, attached to the vertebrae of the thoracic region and together with the sternum form the rib cage. The anterior ribs are much less mobile than the rest.

The limb skeleton is also called the peripheral skeleton. It includes the thoracic and pelvic limbs. The thoracic limb consists of:

• shoulder blades;
• humerus;
• the radius and ulna bones, which together form the forearm;
• seven small bones that form the wrist, and five bones of the metacarpus along with the fingers that form the hand;

The pelvic limb includes:

• five pelvic bones;
• the femur and patella, which make up the thigh;
• the tibia and fibula, which form the tibia;
• seven tarsal bones and five metatarsals, together with the toes, making up the foot;
• phalanges of the fingers (the first finger has 2 phalanges, the other four have three).

Muscular system and skin

Muscles provide the dog with movement - flexion, extension, rotation. There are three types of muscle tissue:

• smooth, making up the walls of blood vessels;
• striated, attached to the skeletal base, more than two hundred such muscles;
• cardiac.

A dog’s skin, in addition to its protective functions, plays the role of a sensor that responds to the external environment and influences. Through it, the pet feels changes in ambient temperature, pain, touch, etc. The skin is penetrated by blood and lymphatic vessels; sebaceous, sweat and aromatic glands; nerve endings; hair roots and muscles. All this allows you to regulate body temperature, remove certain substances from the body, raise the fur and even produce vitamin D when exposed to sunlight.

Dog muscles: 1 - frontal; 2 - chewing; 3 - sternothyroid; 4 - brachiocephalic; 5 - trapezoidal; 6 - deltoid; 7 - shoulder; 8 - triceps; 9 - wide back; 10 - chest; 11 - abdominal external; 12 - gluteal; 13 - tensor fascia of the thigh; 14 - semitendinosus; 15 - biceps femur

The skin consists of several layers:

• the outer epidermis, from which hair grows and dead skin sloughs off;
• the main one, called the dermis, in which nerves, blood vessels, glands, etc. are hidden;
• subcutaneous, consisting of fat and connective tissue.

Internal organs

Inside the dog there are various organs, interconnected into several systems. Below is basic information about the internal organ systems.

With the help of the digestive system, the dog’s body receives many substances necessary for its functioning in the form of food, and also removes undigested residues and metabolic products.

The food swallowed by the dog passes through the esophagus into the stomach. where, under the influence of gastric juice and enzymes produced by the pancreas, it turns into a homogeneous mass. This mass moves through the small intestine. In the process of movement, the body secretes the necessary substances from this mass, which, with the help of enzymes and bile produced by the liver, enter the body through the intestinal walls.

Food undigested by the body enters the large intestine, where under the influence of a new portion of enzymes and thanks to the activity of microorganisms, feces are formed. Feces are eliminated from the body through the anus.

With the help of the respiratory system, the dog inhales air, saturating the body with oxygen, and exhales a mixture of carbon dioxide, water vapor, etc. Through the nose, larynx, and trachea, air is directed to the lungs located in the chest cavity. There, gas exchange occurs between the incoming air and the blood. Due to the fact that the animal's heart is shifted to the left, its right lung is slightly larger than its left.

A dog's breathing rate varies widely, depending on its condition, age, time of day, weather, physical activity, and breed. Small dogs breathe noticeably more frequently than larger breeds. Thus, an adult Japanese Chin in a calm state breathes 22-25 times a minute, and a German Shepherd - 12-14 times. The appearance of a stranger in the dog’s field of vision can also lead to increased breathing.

Thanks to the circulatory system, blood is pumped with the help of the heart through blood vessels that permeate the entire body of the animal. Blood supplies the body with oxygen, nutrients, and frees it from waste products. Blood circulation is carried out through a closed system; the speed of complete blood circulation can range from 13 to 25 s.

The main organ of the system is the heart, located in the chest cavity and shifted to the left. The normal pulse of a healthy dog, corresponding to the heart rate, depends on the breed and can range from 70 to 110 beats per minute (the smaller the pet, the faster the heart beats). The pet's pulse value is determined by the femoral or brachial arteries.

Like other vertebrates, The nervous system of dogs is divided into central and peripheral. The central nervous system (CNS) includes the brain and spinal cord. The brain is the most important organ of the entire nervous system, controlling the functioning of the entire body. It processes information impulses sent by the senses and is responsible for coordination of movement, memory, emotions, etc. Placed in the skull.

Nerve cell: 1 - nerve cell body; 2 - core; 3 shoots; 4 - neuritis; 5 - the membrane forms, together with the neuritis, a nerve fiber; 6 - terminal branches of neuritis

The location of the spinal cord is the spinal canal. It originates from the brain and ends in the lumbar region. In this organ, nerve impulses are formed that are transmitted to the executive organs: muscles, blood vessels, etc. The reflexes of many motor reactions are closed on it.

The nervous system that is located outside the central nervous system is called peripheral. This system is responsible for coordinating movements, managing digestion, responding to danger or stress, or vice versa - optimizing the activity of the animal’s body during the rest period.

Excretory and reproductive

The organs of reproduction and excretion are closely related to each other. The male sex glands, the testes, are located in an external leathery sac called the scrotum. The sperm they produce enters the female's reproductive tract through the penis.

The female gonads, the ovaries, are located inside the body in the area of ​​the lumbar vertebrae. In addition to them, the female reproductive system includes the uterus, fallopian tubes, vagina, and external genitalia. The maturation of eggs in the ovaries occurs cyclically.

The stage of sexual arousal of the female manifests itself in the form of several processes: sexual heat, estrus, ovulation. Sexual heat is the positive reaction of a bitch to a male dog, the desire to get closer to him for sexual intercourse. Estrus externally represents the release of clear fluid from the female’s genitals. Ovulation is the release of a mature egg from the ovary.

Important! The first heat can occur when the bitch is not yet a year old, but this does not mean that she is ready for pregnancy, since the formation of the adult body is not complete and some organs are not developed. Therefore, it is usually recommended to make the first mating at the age of one and a half years.

The dog's excretory system consists of two kidneys connected by the ureters to the bladder. The kidneys, by filtering the blood, secrete urine, which accumulates in the bladder and is expelled through the urethra, which passes through the penis in males or the external genitalia in females.

Sense organs

A dog, like any predator, has well-developed senses. Each of these organs is arranged according to a single scheme: a receptor (perceives information from the outside), a conductor (transmits information to the brain) and a brain center (analyzes information and reacts to it).

The eyeballs act as visual receptors, connected by nerves to the brain. They are placed in the eye sockets and consist of several membranes enclosing the vitreous body. Dogs' vision is different from human vision.

These animals do not distinguish between red, orange, yellow and green, and they perceive everything blue and blue-green as white. But they perfectly distinguish shades of gray. In the dark they see much better than humans. Each dog's eye has its own field of vision. They notice even minor movements of objects well, but visual acuity in dogs is worse than in humans.

The ear as a receptor consists of the outer, middle and inner ear. The external one picks up sounds using the auricle. On average, sound is converted and transmitted to the inner ear. From the inner ear, the information received is transmitted through the auditory nerves to the brain.

Dogs hear over a much wider range than humans - from 12 Hz to 80,000 Hz, i.e. hear ultrasound. They can distinguish sounds of medium intensity at a distance of up to 50 meters (people up to 10 meters), and on a quiet night up to 150 meters.

Did you know? Long-term exposure to noise, including ultrasound, is poorly tolerated by dogs. Therefore, ultrasound is used not only in the training process, but also to scare away aggressive animals.

The receptors responsible for the sense of smell in dogs are located inside the nasal cavity. These are the endings of special nerve cells through which smell sensations are transmitted to the brain.

The dog’s olfactory organs: 1 - inferior turbinate; 2-superior turbinate; 3 - olfactory cavity; 4 - brain cavity

The layer of these cells, called epithelium, is significantly larger in area and thickness than in humans, so a dog’s sense of smell is an order of magnitude superior to a human’s. Pets can smell a scent from more than a kilometer away; they can distinguish up to a million different odors.

Taste buds, called taste buds, line your dog's tongue and mouth. Their endings transmit sensations to the brain. It is not known for certain how exactly a dog tastes different foods. But rewarding your pet with food has been successfully used in training for a long time.

In conclusion, we can say that by understanding at least the basic basics of a dog’s anatomy and physiology, the owner will have a much better understanding of his pet’s behavior and be aware of the problems that he may encounter. Ultimately, this will lead to better mutual understanding between the pet and its owner.

Video: Anatomy of dogs

are our relatively youngest breeds: the Giant Schnauzer, the Doberman Pinscher and the Airedale Terrier, which, precisely thanks to the above-mentioned properties, are used as service dogs.

The group of northern wolf-like dogs and herding dogs descended from a dog, the remains of which were described by the Russian scientist, prof. Anuchin, having found them in excavations near Lake Ladoga. This dog was larger than a turf dog and was named after the Russian scientist-archaeologist, prof. A. Inostrantseva (Canis familiaris Inostranzewi). She is a likely descendant of the Northern European wolf or a hybrid between a wolf and a turf dog.

We derive the group of mastiff dogs from an independent ancestor called Canis familiaris decumanus, about the origin of which nothing is known. But which, with its powerful physique, is most similar to modern Great Danes and ancient fighting dogs, which are known to us from ancient sculptures.

By crossing northern breeds with mastiff dogs, St. Bernards and Newfoundlands were probably created with a calm nature and affection for people, but at the same time sensitivity and fearlessness.

The youngest, in evolutionary terms, the primitive ancestor of our dogs is the bronze dog (Canis familiaris matris optimalae), the remains of which were found in many Bronze Age settlements (about 4-5 thousand years BC). From him came all the breeds of shepherd dogs (German, Belgian, Scottish, etc.), which are similar to him in their size, skeletal structure and skull shape. And finally, in the same century there was a dog, the remains of which were found here. It was of medium size and differed from the bronze dog, first of all, in the shape of the skull, which resembles the shape of the head of modern hounds or brakkas. This dog was named ashy (Canis familiaris intermedius). She was apparently the primitive ancestor of a number of modern breeds of hunting dogs. We explain the great diversity of these breeds by the fact that they arose as a result of crossing the original Ash Dog with other prehistoric breeds.

The only group about whose origins we still know very little is the greyhound. They apparently originated in two places, namely the Eastern European and North African steppes, and are descended from steppe wolves. However, there is no evidence for this. The study of the origin of dogs and individual breeds is extremely difficult precisely because of the great diversity, which depends on the ability of many predators of the canine family to interbreed with each other and produce offspring capable of further reproduction. Man used this property and purposefully selected hundreds of different breeds, many of which have already ceased to exist, and new breeds are being created today.

Dog Anatomy Basics

A dog's body is made up of various organ systems that perform separate functions. From the point of view of the external description of a dog, only those systems are important that form characteristic features that distinguish not only dog ​​breeds, but also the characteristics of individual individuals based on standards - more or less accurate norms for each breed.

Therefore, to describe a dog’s exterior, the skeletal system (bones, cartilage, teeth), muscular and skin systems (skin and its formations) are practically important. Other organs, such as respiratory, vascular, digestive, genitourinary, nervous, etc., which are extremely important for the life of a dog and its existence and are often important for its description (for example, to describe its temperament, dog behavior), on the form bodies are not reflected, and therefore we will not dwell on them.

Skeletal system

The axis of the dog's skeleton (Fig. 1) is the spinal column, at the front end of which there is a skull, and on the sides there are ribs and limbs.

Dog skeleton:

1 - facial part (muzzle), 2 - cranial part, 3 - first cervical vertebra (atlas), 4 - cervical vertebrae, 5 - thoracic vertebrae, 6 - lumbar vertebrae, 7 - caudal vertebrae, 8 - sternum, 9 - ribs , 10 - scapula, 11 - glenohumeral joint, 12 - humerus, 13 - elbow joint, 14 - radius, 15 - ulna (both form the forearm), 16 - wrist, 17 - metacarpus, 18 - fingers (paw), 19 - pelvis, 20 - hip joint, 21 - femur, 22 - knee joint, 23 - tibia, 24 - fibula (both form the tibia), 25 - calcaneus, 26 hock joint, 27 - tarsus, 28 - metatarsus, 29 - fingers (paw).

A dog's skull is made up of the facial and cranial bones that form the cranial cavity, which contains the brain. The front part of the head is wedge-shaped and has a length characteristic of certain breeds. In the same way, certain breeds are characterized by the ratio of the length of the facial part (muzzle) to the length and width of the skull, as well as the transition from the skull to the muzzle, also called a fracture. Rounded zygomatic arches protrude from the spacious eye sockets, forming the basis for the attachment of powerful masticatory muscles.

The lower jaw is attached to the skull by a joint, driven by powerful chewing muscles, allowing lightning-fast and strong compression of the jaws.

Teeth. The upper and lower jaws contain teeth. An adult dog has 42 teeth; puppies have 28 baby teeth. The dental formula for an adult dog is 3, 1, 4, 2, for a total of 42 teeth, which means that in each half of both jaws there are three incisors, one canine and four false-rooted teeth (premolars). In addition, in each half of the lower jaw there are 3 permanent molars, and in the upper jaw there are 2 molars. The first molar in the lower jaw and the premolar adjacent to the molar in the upper jaw are especially powerfully developed and are called carnivorous teeth. The teeth are numbered in each half of the jaw separately and are designated as follows: Incisors are numbered from the middle of the jaw towards the canine, as P1 (hooks), P2 (middle), P3 (edges). There is one canine and is designated by the letter K. Premolars do not always have the same numbering, sometimes they are numbered from front to back, and sometimes vice versa from posterior to anterior, like P1, P2, P3, P4. Molars (permanent molars) are numbered from front to back as M1, M2, M3. In some canine literature, teeth are numbered from hooks in a row from 1 to 20 or, accordingly, to 22, similar to how in dentistry

person. In our country, premolars were previously numbered from back to front, so with permanent molars M1, the adjacent one was P2, and with the canine P3. Currently, they are numbered in reverse, i.e., premolars and molars are now counted from the canines (Fig. 2).

Sometimes in a set of teeth there are fewer teeth developed than 42, and then we talk about poor teeth (oligodontia), sometimes there are more teeth, and then we talk about a supernumerary number of teeth (polyodontia, hyperdontia). The dog must have a full set of teeth. Certain breeds are characterized by the relative position of the teeth in the upper and lower jaws, the so-called. bite. The correct bite for each breed is determined by the standard. If the row of upper teeth covers the lower incisors so that the lower incisors are adjacent to the inner planes of the upper teeth, then this is called a scissor bite (Fig. 3-1).

1-4 - Bite: 1 - scissor, 2 - pincer, 3 - undershot, 4 - undershot or bulldog (depending on the severity)

If the incisors of both jaws touch their cutting edges, then a pincer bite is formed (Fig. 3-2). If the lower jaw is shorter, so that there is a gap between the rows of upper and lower incisors, the so-called. undershot (Fig. 3-3), and when the lower jaw, on the contrary, is longer than the upper, an overshot or bulldog bite is formed (Fig. 3-4).

The spine consists of vertebrae, namely 7 cervical, 13 thoracic, 7 lumbar, 3 sacral (fused and forming the so-called sacral bone) and 20-23 caudal vertebrae. The first cervical vertebra is called the atlas, and the second epistrophy. These two vertebrae are different in shape from all other vertebrae and provide mobility to the head. Convex ribs are attached to the thoracic vertebrae by means of joints, forming the rib cage. The dog has 13 pairs of ribs, including 9 real and 4 false. True ribs are attached below to the unpaired sternum by costal cartilage. The cartilages of the false ribs are interconnected, forming the so-called. cartilaginous costal arch. The chest protects vital organs - the heart and lungs. The convexity of the ribs is characteristic of individual breeds and, as a rule, is indicated in the standard. The lumbar vertebrae form the part of the spinal column between the last rib and the sacrum. The caudal vertebrae form the axis of the tail and are very mobile; In some breeds, the tail is trimmed (docked) in accordance with the standard.

The fore (thoracic) limb is formed by an obliquely set shoulder blade, connected to the humerus by the glenohumeral joint. At the elbow joint, the forearm is connected to this bone, consisting of two adjacent and mutually contacting bones - the radius and ulna. Next comes the carpal joint (wrist), consisting of 7 carpal bones, to which the metacarpus is connected, composed of 5 metacarpal bones, which pass into 4 three-phalangeal and 1 two-phalangeal fingers. The fingers are equipped with strong, non-retractable claws.

The hind (pelvic) limb is connected to the pelvis by the hip joint. The hind limb is formed by the femur. Which is connected to the lower leg at the knee joint,