BONES ANATOMYThe purpose of an individual bone can usually be determined by the shape and its other features. Long bones can be determined as bodily support as well as levers for movement just as the pelvic bone holds a distinctive shape that can be associated with the hips and pelvic girdle. Large bones that hold the body’s structure in place also have large articular surfaces, as well as obvious nodules and markings which allow for tendons and ligament attachments to connect the bones to muscle tissue. A flat surface indicates a large muscular attachment or protection. The end of an articular bone that has nerves or tendons passing over it are likely to have tell tale grooves. Openings through the bone’s structure indicate a place for nerves, tendons, or blood vessel may simply pass through the bone. The basic grouping of bones are indicated by their consistent shape which indicates their function, such as long bones, short bones, flat bones, and irregular bones.
BONES STRUCTURELong bones are designed to function as levers and carry more length than they do width. Generally speaking the bones which are functional for extremities are long bones, such as the femur, the tibia, the fibula, and the metatarsal bones, as well as others.
Short bones tend to resemble a cube and are found in places such as the wrist and the ankle and their function is designed to transfer the flow of movement.
Flat bones may be flat in design to provide a surface for muscle or they may be flat in design to provide protection. Ribs as well as the shoulder bones are designed for protection as are the cranial bones.
Bones such as the vertebrates are considered irregular bones. Irregular bones can not be classified as any other type of bones because their odd shape and their configuration are designed for specialty jobs.
The majority of bones are composed two variations of bone tissue. One type of bone tissue is dense and compact while the other type resembles a sponge material known as cancellous bone tissue. Dense bone is strong with a hard shell exterior designed to protect the inner layers of bone. The bones which are laden with cancellous bone tissue are typically filled on the inner portion of bone with this spongy tissue, wrapped in the tough and strong exterior. Sponge like bone tissue is found in the bones of the skull, known as a diploe, it is snugly between the hard compact bone. This naturally occurring protective measure means that a skull fracture is more likely to crack the outer layer while leaving the softer middle layer intact. This keeps the inner layer that protects the brain tissue well protected.
The long bones of the skeleton are assigned their own terminology to help differentiate between long bones and other bones. For example, the long bone from an arm or a leg has a bone shaft, or a diaphysis, which is the terminology describing the long bone’s dense outer layer which protects the softer inner layer. The softer inner layer is referred to as the medullary cavity and is filled with sponge like soft bone tissue. This cavity is additionally lined with endosteum which refers to lining designed of connective tissue. In the adult human body, the medullary cavity also contains a yellow colored fat like bone marrow substance. It is referred to as yellow marrow because it contains a high concentration of yellow fat deposits.
The sponge like bone tissue is not limited to the core of hard long bones. On the ends of the long bone, the soft tissue is then surrounded by a layer of compact hard bone tissue, and this has been named the epiphysis.
The more familiar bone marrow, red bone marrow, is located in the sponge like bone tissue, tucked away within chambers that the spongy surface of the soft bone tissue creates. In the adult human body, the process of hemopoiesis occurs in the red bone marrow, particular that found in the vertebrates, the sternum, the proximal epiphysis of the femur and the humeri, and in some parts of the ossa coxae.
Joints require more protection than dense bone can offer, thus joints typically have thin hyaline cartilage that protects the joint and allows for a degree of movement. This cartilage is typically in the form of disks or caps, such as on the knee joint.
BONES FACTSBones are living tissue, and like all the living tissue in the human body, they require the transfer of nutrients to stay strong and healthy. Bones are unique in their nutrient design, as they have small openings in the bone known as nutrient foramina which allows the nutrients to pass through the outer layer of dense bone and reach living tissue inside the bone.
As the body grows, it requires bone growth in order for the skeletal system to be fully functional in and adult body. This occurs through a system of plates and fusion. Ossification (the process of the bones fusing together) occurs when the growth of the bone has reached its final stage. Previous to that, epiphyseal plate maintains bone integrity in a growing body. These are commonly called growth plates. These plates are made from cartilage and are somewhat flexible until after ossification. These plates are located in prime areas of the body to allow for full function of the bone at the end of the growth period.
With the exception of the articular cartilage, the bones are covered with dense connective tissue. The muscles can attach here via tendons and high level of vascular activity helps to facilitate appositional bone growth, which means growing in width as well as in length. Fibers that are made up mostly cartilage help to hold the muscle in place as well.
The bones are the heart of the human body’s structure and can not be duplicated by man. Despite artificial bone structures, the intense scientific studies and technological capabilities have not yet discovered a method of producing bone that mimics the human body’s natural bone development.