Internal dog morphology

Skeleton: The bones in a dog's body constitute of the build of the body and they represent 9 percent of the dog's body weight. The number of bones varies from 279 to 282, depending on the dog. The structure of dogs bones is however the same for all breeds. However, the dimensions of these and shape can vary depending on the breed of the dog such as in the shape of the skull. A dog's skeleton can be divided into four parts: the spinal column, thorax, head, and extremities. 

Canine spinal column: Also known as the backbone, is what protects the spinal cord and is one of the most important parts of the skeleton and is largely responsible for holding the bones of the body together. It is made up of many bones called vertebrae.

Canine thorax: Attached to the spinal column the thorax is made up of the rib cage the cartilage on the ribs and sternum. The fist ribs join at the sternum, while the others (known as fake ribs) are not attached at their ends. These ribs are attached by means of cartilage forming an arch. Dogs have a total of 13 ribs.

Canine skull: The length of the dog's muzzle varies drastically within the different breeds. The cranial capacity of each dog also varies from breed to breed. The function of the skull is to protect the brain and its nodes of sight, hearing and taste. In the cranium is where the dog's digestive and respiratory apparatuses and functions begin.  Normally the upper and lower jaws should meet together however in certain breeds there is a tendency for either the upper jaw or lower jaw to protrude beyond what is considered normal and this can often cause problems for the dog.

Canine teeth: Like human children dogs begin with a set of baby teeth (normally thirty two) that begin falling out when the puppy is three weeks old and a set of adult teeth (normally forty two). Dogs should normally have gotten all of their permanent teeth by the time they are eight months old. The forty two teeth are made up of twelve incisors with six on the upper jaw and six on the lower, four canines with two up and two down and twenty four premolars and molars with twelve up and twelve down.

The canine extremities: The dog's extremities are primarily made up of its front and back legs with their respective bones. On their front legs dogs have five toes on each paw whereas on their back legs the paws normally have only four toes.