A callus is a callosity, that is a small area of skin, usually on the foot, that has become thick and hard from rubbing or pressure. Calluses may lead to other problems such as serious infection. Calluses are often caused by badly fitting shoes. The term is also applied to a new growth of osseous matter between the extremities of fractured bones, serving to unite them. Research Callus
In medicine, a fracture is the breaking of a bone. It is simple when the bone only is divided; compound when there is also a wound of the soft parts leading down to the fracture.
A fracture is termed transverse, longitudinal, or oblique according to its direction in regard to the axis of the bone.
It is called complicated if accompanied with dislocation, severe contusions, wounded bloodvessels, or any disease which prevents the union of the bones and causes them to be very easily broken.
A comminuted fracture is one in which the bone is broken into several small pieces at the point of rupture.
An incomplete fracture is one in which only a portion of the fibres is broken.
A stellate fracture is a series of fractures radiating from a centre.
When a fracture takes place there is a pouring out of fluid - lymph - and cells from the blood contained in the vessels of the lining membrane of the bone as well as from the vessels of the soft parts which have also suffered injury. This material surrounds the broken ends of the bone, becomes firm and consolidated, and in about three weeks is hard enough to keep the broken ends in position. A formation of bone then takes place round the seat of fracture. This is called 'provisional callus', because, when the process of repair is completed and true bone has formed to unite the break, it is re-absorbed and gradually disappears. Meanwhile a process of repair goes on between the broken ends, uniting them by the formation of true bone or 'definitive callus'. The more quickly and accurately after the break the broken ends are brought together, the more rapid will be the reunion. The treatment of a simple fractured bone is to bring the portions into their natural position and to keep them permanently thus, formerly by splints of some kind, pasteboard splints, for instance, dipped in warm water, with wooden ones exterior to them; or, as more recently, a mass of plaster of Paris may be used for the same purpose. Research Fracture
When any portion of body tissue has been destroyed by disease or violence, the adjacent tissues at once set to work to repair the gap. Clearly their task will depend on the extent of the gap and the presence of any factors which hinder normal tissue activity. When a clean surgical incision has been made and the edges sewn closely together the gap to be bridged is very thin. On the other hand, if there has been an abscess and a large area of tissue has been dissolved away, the problem is very much greater. There are many factors which infuence the rate of the body's power of healing. Where a gap has been left in the tissues, the 'raw' surfaces are covered with blood clot and any intervening cavity may in fact be filled with blood. From the ends of the capillaries which have been cut on either side, cells grow rapidly into this haematoma (a collecion of blood in the tissues) and form granulation tissue, which is thus a mass of tiny little capillary buds with fibrous tissue cells.
As the days go by, the very rich blood supply enables fibrous tissue to grow rapidly and become more dense, and finally to cement the gap. Weeks later the blood vessels die off and firm fibrous tissue (scartissue) remains. This becomes slowly tighter and tighter. This process we know as contraction, so that what may appear to be quite a large scar shrinks down over a period of months to become sometimes invisible. Perhaps the best example of this is the cavity left by the removal of the slough from a large carbuncle; in a very few months there is a small white, irregular scar marking the centre of the great cavity where the carbuncle existed. If the wound has involved other tissues than connective tissue - for instance, the mucousmembrane of the cheek, or the skin - then the very specialised epithelial lining also grows across as a sheet of cells and covers up the granulation tissue. The same process occurs in the intestinal tract; when an anastomosis (artificial opening between two hollow organs or vessels) has been performed, the cut edges of the mucousmembrane are stuck together temporarily by fibrin, and over a period of days the cells lining the stomach or intestine grow rapidly across the gap. When a bone is broken, repair takes place in a similar way: calcium substances from the blood are deposited in the granulation tissue forming callus. Into this callus the specialised cells which form true bone, migrate from the surrounding damaged bone: over a period of weeks or even months the minute structure is rebuilt to join up exactly with the bone on either side of the break.
The healing power of the body is influenced by many factors. An adequate supply of oxygen is necessary for these tissue repairs, and as oxygen is carried to the tissues by the blood, anaemia results in a very poor healing rate. Vitamins, especially vitamin C, are necessary for the repair of tissues, so that patients whose reserve of vitamin C has been depleted heal more slowly and may in fact not heal at all. Patients who are ill use more vitamin C than the normal healthy individuals and sometimes, unless their requirement is met, a wound may come apart even a week or more after operation, showing no sign of healing whatever. Infection always delays healing as it interferes with the activities of the cells at the edges of the wound. Similarly, if the patient' s general health has been impaired by longstanding disease or bad nourishment his powers of healing are poor, as the substances required for the repair are in short supply. The presence of foreign bodies or a poor blood supply (such as occurs in arteriosclerosis, or if the stitches have been tied too tight) will also delay sound healing. In addition, there are many personal and undetermined factors which must be responsible for the fact that some people heal quickly and others heal very poorly. Age is important; babies and children repair their tissues very much more rapidly than old people. This is because the growing child has much more vitality in all his cells. For example, a fracture of the humerus in a new-born baby may be soundly united in ten days; in an adult the same fracture requires about eight weeks to heal. Research Tissue Repair and Replacement
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Callus
