(This is Session 3. If you are pursuing certification and training in alternative health therapies for canines you should scroll down or begin at Session 1)
Skeletal SystemLike a frame of a house, the skeletal system provides the rugged support for the body to be built. It provides bones against which the muscles work and it provides protection for the vital organs. The vertebral column protects the spine, the skull protects the brain, and the rib cage protects the heart and lungs. The skeletal system also defines a dog’s size and shape. Bones are made up of minerals, of which the major mineral is calcium.
A bone is comprised of several parts. The outside covering of a bone is called the periosteum and it is a hard covering that allows the bones to connect to ligaments and tendons. Another part of the bone which plays an important role in connection to other bone is the hyaline cartilage. The hyaline cartilage allows for smooth movement and little friction where bones connect It is nourished by synovial fluids. It is found in other parts of the body too, but here we are concerned only with its role in the skeletal system as it facilitates movement. Hyaline cartilage, with its friend, synovial fluid, is very strong and flexible, allowing it to be held closely to other bone and still accommodate movement. We will not go beyond these parts of the bone here in detail except to mention that the rest of the bone consists of compact bone, arteries for nutrients to be delivered, bone marrow, medullary cavity and other developing mass. For this level of study we will name the parts of the bone as:
Please Honey, Buy Cheese Not Milk
Periosteum, hyaline cartilage, bone marrow, compact bone, nutritional artery, medullary cavity.
Periosteum; Outer covering
Hyaline cartilage: Connective, protective and strong , slippery and bloodless. (exists without blood flow)
Bone Marrow: Develops red and white blood cells for nutrition and support.
Compact Bone: dense part of the bone we credit for bone strength.
Nutritional Artery: connects the bones nutritional existence with the rest of the body.
Medullary Cavity: A cavity that allows bone to be big but not heavy and stores marrow.
For our study we want to know that the bones need nutrition to form properly and for an entire life, that they are always closely working with muscles, joints and ligaments, and that they give shape, support and strength to the entire body.
The skeletal bones are different shapes and sizes and make up four areas of the skeletal system.:
The Skull and Face: skull, nose and jaw. In more detail you may hear of parietal lobes, frontal lobes and other separations of the different parts of the skull and face bones. We will refer simply to the skull, nose and jaw bones.
The Spine: Consists of 7 cervical vertebrae, 13 thoracic vertebrae, 7 lumbar vertebrae, 3 sacral vertebrae and 18-14 caudal vertebrae in the tail. Yes, the tail is an important part of the body with vertebrae. Never, should it be yanked, pulled or abused.
The Rib Cage: 13 pair of ribs that reach from the thoracic vertebrae to the breastbone or sternum.
Remaining Bones: forelegs, scapula, humerous, radius, unla, carpal bones and phalanges.
Major Bones of the Body
Cranium: The major part of the skull.
Maxilla: Face and nose.
Mandible: Jaw
Teeth: (obvious)
7 Cervical vertebrae: Starting with the atlas (first vertebrae and then the axis (second vertebrae) and then 5 other cervical vertebrae.
13 thoracic vertebrae: Where the ribs join the spine or backbone.
7 lumbar vertebrae: Follow the thoracic vertebrae.
3 sacral Vertebrae: Fused together
Caudal vertebrae of the tail: The 18-24 vertebrae that are found in the tail.
Pelvis: Hipbone
Femur: Bone from hip down to tibia.
Tibia: From the femur to the tarsus.
Tarsus: Small bones like bones in wrist on humans
Metatarsus: Smaller bones from wrist to phalanges.
Phalanges: Claws or “fingers”.
Sternum: Where ribs meet at bottom of frame.
Unla: Bone parallel to radius in foreleg.
Radius: Larger of the two middle leg bones in the foreleg and the one on the front side of the leg.
Humerous: Large bone in foreleg similar to a thigh in a human.
Scapula: The large plate at the front of the chest.
Ligaments
Ligaments are the connective tissues that join bone to bone. (Tendons differ in that they connect bones to muscle and we’ll discuss them in the next chapter). The areas where bones join each other are called of course, joints. These are crucial areas to be concerned with when it comes to diet, nutritional therapy, exercise, massage therapy and acupressure. Joints are sometimes the weakness in the body, due to various reasons, that can cause pre-mature aging, immobility, pain and even death…as a result of the need to euthanize.
We will not learn the plethora (many) joints and ligaments of the body in this program; however, you already know they are found wherever bones meet. Ligaments are extremely strong, and they must be, in order to keep bones in place but still allow for movement. Because of the limited blood supply to ligaments, they take longer to heal when sprained or injured than does a muscles which get a large amount of blood supplied to them. Because ligaments are not extremely “elastic” they can be over worked and loose strength requiring surgery to repair.
Ligaments attach to the periosteum of the bone and the periosteum in the covering of the bone however, where bone meets bone is where we will find no periosteum, rather we find the hyaline cartilage where bone meets bone. The cartilage is the part of the bone that engages in moveable contact with another bone and the cartilage is the slippery part that allows for very little friction and quality movement. This is the part of the bone that is not covered in periosteum. It may be somewhat like wearing a mask on your face. There is an opening for your nose and mouth allowing you to breathe and eat, and the rest of the face is covered and protected. The mask is then the periosteum and the open part is the hyaline cartilage. So in review of ligaments and bone connection; we have ligaments on each side of the bone adjoining it together with another bone by connecting to the periosteum of each bone and, at the meeting ends of the two bones, we have the hyaline cartilage that allows for little or no friction and enhances quality movement. The cartilage is sometimes referred to as articular hyaline cartilage, articular means that it is located where the bones move and rub together. This is known also as a part of the joint. So then here is what parts are included in a joint; the bones, the ligaments, the articular hyaline cartilage and one last thing; synovial linings and fluid. The synovial lining is simply, a layer of ligaments that produce a fluid called synovial fluid that lubricates and enhances the work of the joint.
Seems like a lot to know doesn’t it? Well, there is even more, however, this is really sufficient for the purposes of pet therapy because we are most concerned with things like, why it’s important to nourish moveable joint with proper diet, why it’s important to exercise, when and how to exercise, and for other reasons. Here is an example of why this knowledge plays an important role in pet therapy.
We know that bone is made largely of calcium and calcium is always forming and hardening to give the bone its compact bone which is the strength of the bone. As a puppy, many large breed dogs are over exercised. When a Great Dane is a puppy its bone takes longer to calcify and harden. If we over exercise the bone and joints we may put too much exertion on soft bone and cause uneven growth which can lead to a painful and jagged bone. This jagged bone can cut through the hyaline cartilage and synovial linings to create much discomfort. Allowing the bones plenty of time to grow and calcify can play a huge part in the quality and length of life for a large breed dog that typically has a short life span. Exercise for any dog should be well thought out and not ignored. A good reason for this is because of what we know about how moveable joints and bones grow and operate.
A last word on bones and joints; most bones and joints are moveable however, there are some joints in the body where there is not movement and these are bones and joints we should still know about. These consist of the skull, the sacral vertebrae (fused together), and the bones forming the pelvis.
TEST
1) Make a crude drawing of a dog and write the names of the bones at the parts of the body where you would find each bone. Do this, three or four times, and say the names out loud as you identify the area and write the name of the bone.
2) Say and write the parts of a bone and briefly describe each.
3) What are the four general areas on the dog that make up the skeletal system?
4) What are the major parts of a moveable joint?
5) What do we call the bone covering?
6) Why does it take a ligament longer to heal than a muscle if it is sprained?
7) What is the name of the cartilage that allows bone to move against bone?
8) Name one unmovable joint in the body.
9) What is the strength of the bone called?
10) What is the name of the lubricating fluid in a joint?
ANSWERS
1) Check your work with the chart.
2) Check your work. (Please Honey, Buy Cheese, Not Milk).
3) Skull and Facial Bones, Spine, Rib Cage, Remaining Bones.
4) Bones, hyaline cartilage, ligaments and synovial fluid or lining.
5) Periosteum.
6) Little blood flow.
7) Hyaline Cartilage
8) Pelvis, sacral joints or skull.
9) Compact bone.
10) Synovial fluid.
You should now know the parts of the nervous system and their various functions, you should also know the skeletal make-up of a dog and be able to discuss the parts of bones and name the major bones, skeletal areas and the parts of a joint. The best way to study these is to pretend you are explaining them to a class or write it out while you say it out loud. Pretend you are the student and the teacher at the same time and ask the student a question and answer it. GOOD JOB!