The Axial Skeleton #MedicalHealthWorldwide

The Axial Skeleton

Within the framework of the axial skeleton lie all the most vital organs of the body. People have gone on living with the loss of a hand or a leg – indeed, with the loss of any or all of their limbs. But nobody can live without a brain, a heart, a liver, lungs, or kidneys – all of which are carried within the framework of the axial skeleton.

The Skull

The bones of the skull have as their most important function the protection of the brain and sense organs. There are also, of course, the jawbones that support the teeth and gums and which enable us to bite and chew our food.
Most of the skull appears to consist of a single bone – a hard, unbroken dome. Actually, the brain cage or cranium consists of eight individual platelike bones which have fused together in the process of growth. At birth, these bones are separated, causing the soft spots or fontanelles we can readily feel on a baby’s brain enlarges, the bones grow along along their edges to fill in the fontanelles, finally knitting together in what are called suture lines, somewhat resembling inexpertly mended clothes seams. Along the suture lines, the skull bones continue to grow until the individual’s mature skull size is reached.

Teeth

The hardest substance in the human body is the enamel that covers the exposed surface of a tooth. Below the gum, the tooth’s outside surface is composed of somewhat softer cementum is a bonelike substance called dentin, which covers the soft interior of the tooth called pulp. Pulp is serviced by blood vessels and nerves through the root or roots of the tooth. The passageway of nerves and blood vessels that lead up through the tooth from the gum sockets is called root canal. Tooth and gum are stuck to each other by a tough, adhesive tissue called periodontal (or peridental – “surrounding the tooth”) membrane.

Read More

How the Bones of the Skeletal System Work Together #MedicalHealthWorldwide

How the bones of the skeletal system work together.

A newborn baby normally has 33 vertebrae making up its backbone; but by the time a person reaches adulthood, the number of individual vertebrae has shrunk to 26.

The explanation is during the growth process, the nine bottom vertebrae fuse naturally into just two. In like fashion, we “lose” some 60 bones as we grow up. Some otherwise perfectly normal adults have “extra” bones or “missing” bones. For example, although the normal number of ribs is 12 pairs, some adults may have 11; others may have 13 pairs.

Even a practicing physician might be hard-pressed to identify each of our 200-plus bones and describe the function. An easier way to gain a general understanding of the various functions, capabilities – and weaknesses, too – of our bones is to visualize the skeletal system as a standing coatrack, say, about six feet high.

Call the central pole the backbone. About ten inches down from its top (the top of your skull) is a horizontal crossbar (your shoulders – collarbones and shoulder blades), approximately a foot-and-a-half across. Sixteen or so inches below the bottom of the top crossbar is another, shorter, crossbar, broader and thicker – the pelvic girdle. The coatrack with its two crossbars is now a crude model of the bones of the head and trunk, collectively called the axial skeleton. Its basic unit is the backbone, to which are attached the skull at the top, then the bones of the shoulder girdle, the ribs, and at the bottom, the bones of the pelvic girdle.

By hanging down (or appending) members from the two ends of the top crossbar, and doing the same at the lower crossbar, we would simulate what is called the appendicular skeleton – arms and hands, legs and feet.

Read More