The chief component is the skull on top housing the brain. This is held in the right position by the vertebral column, a series of very solid bones like cotton reels. This is the backbone. The spinal cord runs from the brain housed in the skull, down the spinal canal, giving off nerves at the junction of each vertebral bone. These supply the various organs at successive levels.
We have the shoulder girdle above, which gives rise to the upper limbs, the arms and hands. The lower part of the vertebral column is associated with the pelvic girdle, a circle of bones housing the pelvic organs. From there we go to the lower limbs, the legs and feet.
Hyaline cartilage cells in the growth plate multiply, move down the bone and produce a calcified matrix. The cells die, leaving spaces. Osteoblast cells produce bone to fill the spaces and replace the matrix, the abdominal cavity, containing the intestinal organs.
Where a bone joins or “articulates” with another, a joint occurs. This enables the part to bend or rotate, and freedom of movement here is essential. The bones are held together at this level by strong strap like ligaments and fibers to form the joint’ capsule.
The bony surfaces are covered with a thin, shiny membrane, and this is covered with an oily liquid, synovial fluid.
Just as joints in machines need ball-bearings and moisture to allow continual freedom of movement, so the body joints need constant oiling. Fortunately, this is performed automatically by nature. But just as man-made joints may become rusty, worn and not move freely or quietly, so the human joints may similarly become corroded. The surfaces may become rough and pitted. Wear and tear, lack of adequate fluid, the presence of infection, or old age may all play a part.
It’s usually a problem of advancing years. But some important ones may occur, and it’s worth noting some of the more likely. I would point out that early attention to any obvious bone or joint disorder requires prompt attention. The sooner this is dealt with, the better. Mothers should never neglect these disorders, believing that they happen only in older adults.