The central cup-shaped depression of the lower end of the sternum and corresponding cartilages, sometimes met with, has been referred to in a previous chapter (see page 12).
The movements of the chest in inspiration must be carefully noted. Sometimes we find a general exaggeration of movement combined with im perfect expansion of the chest-wall. This abnormality indicates a pressing want of air from some impediment to the efficient expansion of the lungs. When bilateral, it is seen in cases of catarrhal pneumonia, in advanced phthisis, and in double pleurisy and hydrothorax. When unilateral, it may be produced by one-sided pleurisy, pneurnothorax (a very rare condi tion in the child), extensive fibroid induration, or condensation of lung from a former pleurisy with firm pleural adhesions.
In early life the thoracic walls yield readily to the pressure of the ex ternal air, and this pliancy is especially noticeable in infants and rickety children. Consequently in them dyspncea is often indicated by more or less retraction of the chest-wall in inspiration. This retraction is mostly in the infra-mammary region, and in pronounced cases may produce a deep horizontal furrow across the base of the chest at the level of the en siform cartilage. If the retraction is limited to this part, it indicates in most cases a catarrh of the inferior lobes of the lungs, which are insuffi ciently filled with air ; but if the ribs are very soft from rickets, the pression may be noticed in ordinary respiration although the "lungs are sound. Sometimes the soft parts of the chest also sink in. The intercos tal spaces are hollowed ; the suprasternal notch and supraclavicular spaces are excavated ; and if the dyspncea reach an extreme degree, the lower half of the sternum with its attached cartilages is depressed into a deep pit at each inspiratory movement. When the retraction is thus pronounced, there is usually an impediment at the upper part of the trachea. Retrac tion to this degree is seen in membranous and stridulous laryngitis, in narrowing of the glottis from any cause, and in cases of lodgement of a foreign substance in the upper part of the windpipe. Still, even in some cases of pleurisy with effusion, marked retraction is seen on both sides of the chest although the impediment to full inspiration only affects one lung.
of one side of the chest can sometimes be detected by the eye ; but it is more accurately estimated by the cyrtometer.i A tracing made from this instrument upon paper shows immediately if one side of the chest be larger than the other. A characteristic sign of pleuritic effu sion is dilatation and squareness of outline of the affected side.
Unilateral shrinking, from fibroid induration, or old pleurisy with firm adhesions, may be also readily estimated by the same means.
Deficiency of movement of the chest is sometimes better appreciated by the hand than by the eye. The hand also detects vibration of the chest wall, if this be present. In children, however, there is seldom a normal fremitus when the child speaks or cries ; for in the high-pitched notes which alone escape from the childish larynx the vibrations succeed one another too rapidly to be readily perceptible by the hand. Consequently, unilateral absence of this sign, which in the adult is an important means of distinguishing between consolidation of the lung and liquid effusion in the pleura, fails us in the case of young patients. Even when detected, vocal fremitus furnishes no certain indication. If present on the sound side, it may be felt strongly over a liquid effusion, for the vibration is readily conducted by the thoracic wall from one side of the chest to the other. I have known it to be felt strongly on the affected side in a case of recent absorption of pleuritic fluid, although almost absent on the sound half of the chest ; and again, in a case of apparently exactly similar kind it has been completely absent over the seat of disease, although present else where.
A rhonchal or friction fremitus is much more common than a vocal vibration in the young subject, but the sign is of little value. Fluctuation can sometimes be discovered in the interspaces in cases of pleuritic effusion and is a valuable sign of the presence of fluid. To detect it, a finger of each hand should be placed at the two extremities of the same interspace. The impulse of a gentle tap is then often conducted distinctly through the fluid from one finger to the other.