Chapter XIV

.

The osseous lesions of rickets differ from those seen in osteomalacia, since in the latter the softened tissue is practically decalcified bone, while in the former case most of the affected tissue has never gone so far as genuine bone formation, but is arrested in its perverted state.

The result of rickety changes in the skeleton is a thickening of the shafts of the long bones, of the outer table of flat ones, of the epiphyseal extremities of shafts, and frequently a stunting of their development, so that they do not attain their normal length. The periosteum is also affected in rickets, with the result that when the changes occur, mostly subperiosteally, there are warpings and curvings of the bone shafts, while so long as the disturbance is epiphyseal more or less abrupt curvatures and angular deformities will be produced as the result of muscle action. So marked are the changes in some instances that it has been stated that bones may even lose three-fourths of their calcium salts. When rachitic bones are so soft as to be easily cut with a knife, marked deformities occur as the result of muscular activity. (See Plate XI.)

In the extremities we see _bow-legs_, _knock-knees_, _clubbing of the ends of the long bones_, bending of the neck of the femur, _flat-foot_, _club-foot_, etc.; while the clubbing of the bone ends also may be well marked in the bones of the upper extremity, where, however, marked deformity is less common, because the upper extremity does not bear the weight of the growing body. In the skull the bones remain soft and yielding to pressure, with a tendency to return to their original membranous condition, and this is the condition comprised under the term _craniotabes rachitica_. The _fontanelles always remain open_ for an undue time; the sutures are broad and membranous. The _bones of the face grow less rapidly_, giving to the face a disproportionately small size; _dentition is delayed_ and the _teeth decay easily_. The upper incisors often project far over the lower.

In the thorax there are enlargements of the sternal ends of the ribs, causing a row of nodules referred to as the _rachitic rosary_. The ribs tend to sink in, the sternum to be protruded forward, and the deformity known as _pigeon-breast_ becomes often pronounced. Curvatures of the spinal column, especially _kyphosis_, are common, and distinct degrees of _lateral curvature_ are frequently begun as rachitic deformities, to be magnified by perverted muscle action as the child grows older. In the pelvis the innominate bones approach each other, causing the pelvic cavity to become contracted, or the sacral promontory projects too far, or in various other ways the normal pelvic diameters are so far compromised that _rachitic deformities of the pelvis_ constitute the most common and serious obstacles to normal labor in adult women, and are frequently the cause of major obstetric operations.

While the rachitic changes in the osseous system are the most distinctive and easily recognized, numerous other organs and tissues of the body are more or less seriously compromised. _Ventricular dilatation_, leading to chronic _hydrocephalus_, is one of the common results of rachitis of the skull, which may be followed by convulsions and terminate fatally. _Porencephalon_ and _cerebral sclerosis_ may also ensue. Disturbances of digestion are common in rickety children--the _liver_ may decrease in size or become much enlarged; the _spleen_ often enlarges, sometimes to enormous dimensions. In various other parts of the body there are the same expressions of malnutrition as are met with in tuberculous disease. Rickety children _perspire easily_, particularly at night, when the head will often be found bathed in perspiration. They are fretful and irritable, as a rule, and difficult to control. A child with protuberant belly, due to enlargement of liver and spleen, as well as to crowding of pelvic organs, with relaxation of abdominal walls, and a contracted and distorted thorax, the skull flattened on the top, clubbed bone ends, a history of resting badly at night and sweating profusely, constitute a clinical picture of rachitis so marked that it can be recognized at a glance. Between this picture in its worst forms and the slightest deviation from the ideal type there may be met all degrees in manifestations of rickets in the children of the rich or the poor, while in adults may often be seen evidences of that which prevailed during early childhood. In order that all these features may be made out the child should be stripped and examined from head to foot.

_Laryngismus stridulus_ is a frequent accompaniment. It may be followed by general convulsions and tetany. (See