Rickets (Lat. rachitis, from Gr.Rickets 1400165 , the back bone), a disease of children characterized by an arrest of ossification, and leading to deformity, chiefly of the lower limbs. Rickets rarely occurs before the child is 12 months old, and commonly first shows itself in the second year. It is most frequent among those who inherit unhealthy constitutions, and who are ill fed or confined to a damp and badly ventilated atmosphere. According to Trousseau, 90 out of every 100 children affected with rickets have been either brought up entirely by hand or have been prematurely weaned. Very frequently the disease supervenes on some exhausting and long continued illness. Trousseau thinks the tardy evolution of the first teeth is indicative of a tendency to rickets. The first symptom of the complaint is an enlargement of the joints, the wrists, knees, etc. Afterward the long bones, particularly those of the lower extremities, give way under the weight of the body, and become bent, sometimes in one, sometimes in another direction; often the ribs are pressed in and the sternum pushed outward, making the child what is termed chicken-breasted; the bones of the pelvis and those of the spine become variously bent and deformed.

This is due to a deficiency in the proportion of calcareous matter in the bones, which renders them less rigid than natural and liable to yield to the increasing weight of the body. The deformity of the chest produced in this manner may be so great as to seriously interfere with the functions of the heart and lungs. The bones of the head are never deformed, though rachitic children have frequently large heads, and the fontanelles are late in closing. During the progress of the disease the patient is pale and languid, and has a deficient or irregular appetite. It is very rarely fatal; after an uncertain period the appetite returns, the child recovers strength and flesh, and the bones attain their natural firmness; in after life the bones affected are found to be unusually hard and compact. - The treatment of rickets is mainly by a nutritious, digestible diet, fresh air, suitable clothing, and passive exercise. Tonics and chalybeates may be employed, and the tepid salt-water bath may be found useful.