A practical treatise on disease in children.

  • Smith, Eustace, 1835-1914.
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: A practical treatise on disease in children. Source: Wellcome Collection.

Provider: This material has been provided by the Harvey Cushing/John Hay Whitney Medical Library at Yale University, through the Medical Heritage Library. The original may be consulted at the Harvey Cushing/John Hay Whitney Medical Library at Yale University.

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    dition, the supply of lime salts be actually reduced, rickets is set up with still greater certainty. Morbid Anatomy.—In looking at a case of well-marked rickets the eye is at once arrested by the enlargement of the epiphyseal ends of the long bones and the deformities of the skeleton which result from softening of the osseous framework. In rickets the bones are affected in three ways. Growth, although not completely arrested, is retarded and rendered irregular ; ossification of parts still remaining cartilaginous is interfered with, and bone already ossified is softened. When a longitudinal section is made of one of the long bones the whole structure appears deeply red- dened from intense congestion. The epiphysis is very large, and the in- crease in size is due chiefly to an enormous development of the cartilage, which is preparing for the reception of the calcareous salts. The layer of cartilage into which the new bone is advancing is called the zone of calcifi- cation. That next in order, in which the corpuscular elements arrange themselves in vertical columns in preparation for the approach of the earthy deposit, is called the zone of ■proliferation. These two zones are greatly thickened and are not separated, as would be the case in the hone of a healthy child, by a well-defined straight line of demarcation. In the rickety epiphysis the new bony tissue, instead of advancing by regular steps into the zone of calcification, no one point being in advance of an- other, shoots up irregularly, so that lines or little islets of calcification are seen far up in the proliferating zone, while on the other hand specks and streaks of uncalcified cartilage are left far below the line of earthy deposit completely surrounded by bone. Moreover, medullary spaces are formed in unusual places, and appear even in the proliferating zone of cartilage far in advance of the margin of ossification. The cartilage cells become the seat of calcareous impregnation,1 and are in many cases converted into bone corpuscles. Small isolated masses of lime can also often be seen scattered through the matrix—enough in many cases to give a dotted ap- pearance to a section of the cartilage. Changes similar to those described in the epiphyses take place at the surface of the shaft of the long bones and in the flat bones. The perios- teum becomes excessively thick and very vascular, and is connected so firmly with the bone beneath that it cannot be detached without fragments of the latter being stripped away with it. Its connective-tissue corpuscles undergo rapid proliferation and become transformed directly into hone corpuscles. The calcifying process is irregular here as it is in the epi- physes, so that layers of firm bony tissue are interspersed with others composed of a fibrous matrix containing connective tissue or bone cor- puscles and medullary spaces. In the flat bones, especially those of the skull, the irregularity with which calcareous matter is deposited is well seen. The new porous bone occupies chiefly the surface and edges. In the cranial bones a special change is often found. In certain spots the bone becomes excessively thin and transparent (cranio-tabes). This con- dition is due to deficient deposit of lime salts in the external layers and absorption of the soft tissue in places, here and there, from the pressure of the brain. Bones in which ossification is thus delayed and perverted are usually soft. The softening is the consequence of the smaller proportion of earthy 1 It has been doubted whether this change occurs in healthy ossification, for in the normal process the calcification of the intercellular matrix which surrounds the carti- lage cells conceals the latter from view. In rickety bone the calcifying granules are deposited first in the cells, so that the changes in them can be distinctly seen.