Anomalies of volume manifest themselves as irregularities in magnitude, and as their opposite, diminutiveness, both being either congenital or acquired. They are often relative only, that is, applicable to one period of development or of life. Again, their significance and import may be limited to the proportions of the organ concerned, as in small-ness of the brain; in enlargement of the heart. Finally, they refer, either uniformly or unequally, to the entire body or to individual organs.

Abnormal Magnitude

Congenital abnormal magnitude is sometimes general. In relation to the entire body it is termed gigantic growth - macrosomia. Some children are born inordinately large and powerful, and endowed with other marks of precocious development besides; for instance, closure of the sutures, unusual strength and length of hair, extrusion of one or more teeth. Others, impelled by innate predisposition, undergo preternatural growth during youth, and eventually arrive at dimensions exceeding the ordinary standard - in a word, grow up giants. Giant stature may depend upon the equal and proportioned lengthening of all the parts, or upon the predominant length of certain sections of the body, especially of the lower extremities. Giant stature does not needs imply corresponding development of the substance of organs and parts, certain of which may possibly have been checked in their growth; for example, the muscular system, the heart, the brain, the adipose tissue, the organs of generation.

Preternatural dimensions of individual organs of the body, both congenital and acquired, are of far more frequent occurrence. These originate in a primary anomaly or in excessive plastic activity of the germ, or, again, in hypertrophy, or in the dilatation of hollow organs, or, lastly, in a variety of diseases in which the textures of organs become involved at different periods of intra- and of extra-uterine life. These last consist for the most part, in hyperemia, inflammation, and all kinds of heterologous formations. Congenital enlargement sometimes imports arrest of development, as, for example, a preternaturally large thymus gland.