#Osteogenesis Imperfecta#, #Fragilitas Ossium#, or #Congenital Osteopsathyrosis#.—­These terms are used to describe a condition in which an undue fragility of the bones dates from intra-uterine life.  It may occur in several members of the same family.  In severe cases, intra-uterine fractures occur, and during parturition fresh fractures are almost sure to be produced, so that at birth there is a combination of recent fractures and old fractures united and partly united, with bendings and thickenings of the bones.  Large areas of the cranial vault may remain membranous.

After birth the predisposition to fracture continues, the bones are easily broken, the fractures are attended with little or no pain, the crepitus is soft, and although union may take place, it may be delayed and be attended with excess of callus.  Cases have been observed in which a child has sustained over a hundred fractures.

The bones show a feeble shadow with the X-rays, and appear thin and atrophied; the medullary canal is increased at the expense of the cortex.

In young infants in whom multiple fractures occur the prognosis as to life is unfavourable, and no satisfactory treatment of the disease has been formulated.  If the patient survives, the tendency to fracture gradually disappears.

#Hypertrophic Pulmonary Osteo-Arthropathy.#—­This condition, which was described by Marie in 1890, is secondary to disease in the chest, such as chronic phthisis, empyema, bronchiectasis, or sarcoma of the lung.  There is symmetrical enlargement and deformity of the hands and feet; the shafts of the bones are thickened, and the soft tissues of the terminal segments of the digits hypertrophied.  The fingers come to resemble drum-sticks, and the thumb the clapper of a bell.  The nails are convex, and incurved at their free ends, suggesting a resemblance to the beak of a parrot.  There is also enlargement of the lower ends of the bones of the forearm and leg, and effusion into the wrist and ankle-joints.  Skiagrams of the hands and feet show a deposit of new bone along the shafts of the phalanges.

TUMOURS OF BONE

New growths which originate in the skeleton are spoken of as primary tumours; those which invade the bones, either by metastasis from other parts of the body or by spread from adjacent tissues, as secondary.  A tumour of bone may grow from the cellular elements of the periosteum, the marrow, or the epiphysial cartilage.

Primary tumours are of the connective-tissue type, and are usually solitary, although certain forms, such as the chondroma, may be multiple from the outset.

Periosteal tumours are at first situated on one side of the bone, but as they grow they tend to surround it completely.  Innocent periosteal tumours retain the outer fibrous layer as a capsule.  Malignant tumours tend to perforate the periosteal capsule and invade the soft parts.