Anatomical plate of canine osteology

The anatomy of the dog begins with its osteology. In the illustration of canine osteology by En Chair et en Os, the goal is to provide a clear representation of the dog's bone morphology, specifically for a large breed (the model used is an adult German Shepherd). This chart is a perfect gift for veterinary students, animal osteopathy students, or anyone interested in canine anatomy. The canine osteology anatomical chart will be accompanied by a chart of the muscles, as well as the viscera and the dog's nervous system. The collection is perfect for decorating a veterinary clinic, a student's room, or any space that welcomes our four-legged friends.

The dog's head

The bones of the dog's skull

The anatomy of the dog's bony skull consists of about 50 bones, depending on the breed and size, and differs from the bones of the human skull. From front to back and top to bottom, in a lateral view, we can practically identify the incisive, nasal, frontal, maxillary, parietal, pterygoid, mandible, temporal, and finally the occipital bone.

Other parts of the skull, located internally, also exist. These include the ethmoid, lacrimal, presphenoid, palatine, basi- and alisphenoid, and the tympanic ring.

Depending on the dog's breed, the shape of the skull will change; compare a Chihuahua to a Leonberger, and you can imagine the number of differences within the same animal species.

Canine hyoid apparatus

Also called the hyoid bone, the hyoid apparatus is formed by a group of bones with fibrocartilaginous properties attached to the temporal bones and suspended from the base of the skull between the branches of the two mandibles. This structure supports the tongue, pharynx, and larynx.

The dog's hyoid apparatus varies significantly from the human hyoid bone. It is generally composed of 9 bones: the stylohyoid, epihyoid, thyrohyoid (also called the greater horn), the basihyoid (which is the body), and finally the ceratohyoid bone (the lesser horn).

 

The dog's trunk

The dog's cervical vertebrae

There are seven cervical vertebrae in dogs, as in most mammals (with very rare exceptions), which form the bony base of the neck, unlike the human cervical vertebrae.

The dog's cervical spine and head form a balance system. It is adapted to the specific type of locomotion of each dog breed. Cervical vertebrae are slender and very short in humans, whose head rests on their stack, whereas they are stronger and broader in dogs.

The body of canine cervical vertebrae has a well-marked ventral crest, which increases in height caudally, ending in a tubercle. This crest does not appear on the first or the last vertebrae.

The atlas and axis possess a particular anatomy that requires a more in-depth study, covered here.

The dog's thoracic vertebrae

The dog has 13 thoracic vertebrae, also called dorsal vertebrae, unlike humans who have 12 thoracic vertebrae. They form the axis of the dorsal wall of the thorax and are characterized by their articulations with the ribs. Each corresponds to a pair of ribs, each articulating via its tubercle with the transverse process of the vertebra of the same rank.

The bodies of the dog's vertebrae widen progressively and generally with low intensity from the first to the last thoracic vertebrae. Due to the dog's anatomy, the first thoracic vertebrae are still broad, the caliber decreases in the upper levels, and then increases again.

The dog's lumbar vertebrae

The dog's lumbar vertebrae form the base of the kidney region between the thoracic vertebrae and the sacrum. They are remarkable for the significant volume of their bodies and the development of their massive transverse processes. There are seven in the dog, unlike the human who has 5 lumbar vertebrae.

 

The dog's sacrum

The base of the pelvic region, the sacrum, is a single bone resulting from the fusion of the sacral vertebrae. Articulated at the front with the seventh lumbar vertebra and at the back with the first caudal vertebra, it joins laterally with the hip bones, with which it forms the pelvis. The human pelvis is different from the dog's pelvis.

The dog's sacrum is formed of three vertebrae fused early, compared to the human sacrum, which includes the fusion of five sacral vertebrae.

The dog's tail

The dog's caudal vertebrae form the base of the tail's osteology. Their equivalent in humans is the coccyx. Their number is highly variable, even within the same species, depending on the breed (some dogs have only a very short tail, like cats). With the exception of the first few, they are incomplete, and the last ones are reduced to their bodies.

The dog's forelimb

The dog's shoulder

In domestic mammals, the thoracic limb does not clearly detach from the trunk until the elbow, or even lower at the proximal part of the forearm. The shoulder and arm are attached against the lateral wall of the thorax, covering the first six ribs. This is unlike the human upper limb.

The shoulder is formed for the most part by the scapula (formerly the shoulder blade) and forms the scapular region with the humerus. It is poorly defined in the dog. It connects to the neck via the prescapular region, while its lower edge blends with the arm, and dorsally, it continues into the withers. The point of the shoulder is formed by the scapula, and behind it lies a slight depression, known as the shoulder defect.

The dog's arm and elbow

The anatomy of the dog's arm is much shorter in proportion than in humans. It follows the caudal edge of the shoulder and the point of the shoulder to continue into the elbow. You can compare it to the anatomy of the human upper limb.

The elbow, formed by the humerus and the ulna, joins the arm to the forearm. It shows a flexion groove in the front, the crook of the elbow, and in the back, a strong relief corresponding to the bony protrusion of the olecranon: the point of the elbow formed by the ulna.

The dog's forearm and paw

The anatomy of the dog's forearm constitutes the antebrachial region. Its medial side features the radius. The lateral side is formed by the ulna. You will find a difference with the anatomical chart of the human hand flexors and the anatomical poster of the human hand extensors.

The paw follows the forearm and forms the distal part of the thoracic limb. It contains three main levels: the carpus, the metacarpus, and the digits, which in principle have three phalanges each.

The carpus forms the wrist region, which is followed by the metacarpals and finally the metacarpophalangeal region.

The dog's hind limb

The dog's pelvis and thigh

The dog's anatomy also describes its pelvis. It is composed of the sacrum, ilium, and femurs. The function of the pelvic limbs is to support the body and propel it. It is firmly articulated with the vertebral column. It is only very slightly comparable to the anatomical chart of the human lower limb.

The skeleton of the dog's thigh includes the femur. The latter is a long, asymmetrical, and paired bone. It is articulated at its proximal end to the acetabulum of the hip bone and at its distal part to the bones of the lower leg. Almost vertical in humans in a normal standing position, it is oblique in dogs.

The dog's lower leg and foot

The skeleton of the dog's lower leg is homologous to that of the forearm. Like the latter, it consists of two bones: a medial one, which is the tibia, and a lateral one, called the fibula (formerly the peroneal bone). Added to these two bones is the patella, which completes the femorotibial joint and plays a role in the leg comparable to that of the olecranon in the forearm. It is very different from the anatomical chart of the human foot.

The dog's foot is the autopodium of the pelvic limb. Its skeleton comprises three parts, homologous to those of the hand: the tarsus, which is formed of two rows of short bones; the metatarsals, long bones placed parallel to each other; and finally the digits or toes, placed in extension of the metatarsal bones and each consisting in principle of three phalanges.