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The girl correspondingly is transformed into a vivacious, gay, nervous and apprehensive butterfly, or a sedate, dreamy, bashful, or even morose moth. It is interesting to note that poise, mental equilibrium, is not established until physical growth ceases, marked by a cessation of growth of the long bones known as ossification of the epiphyses. Poise seems to be controlled by the ante-pituitary.
It may be called for later if the limb is likely to be useless, as, for example, when the whole shaft of the bone is dead without the formation of a new case, when the epiphyses are separated and displaced, and the joints are disorganised. Flat bones, such as the skull or ilium, must be trephined and the pus cleared out from both aspects of the bone.
So long as the epiphyses are distinct from the bones, the growth of the animal is proceeding, but it ceases so soon as the consolidation is complete.
In the upper limb the more active epiphyses are at the shoulder and wrist, and these also are the last to unite. The activity of the epiphysial cartilage may be modified as a result of disease.
As a datum for his conclusion, FLEURENS cites the instance of one young elephant in which, at 26 years old, the epiphyses were still distinct, whereas in another, which died at 31, they were firm and adherent. Hence he draws the inference that the period of completed solidification is thirty years, and consequently that the normal age of the elephant is one hundred and fifty.
The diaphysis is also nourished by numerous blood vessels from the periosteum, which penetrate the cortex through the Haversian canals and anastomose with those derived from the nutrient artery. The epiphyses are nourished by a separate system of blood vessels, derived from the arteries which supply the adjacent joint. The veins of the marrow are of large calibre and are devoid of valves.
Bones formed entirely in cartilage are exempt, namely, the tarsal and carpal bones, the epiphyses of the long bones, the sternum, and the bodies of the vertebræ. Bones formed entirely in membrane, that is, those of the face and of the cranial vault, are also exempt.
Anatomy and physiology Regeneration of bone Transplantation of bone. #Surgical Anatomy.# During the period of growth, a long bone such as the tibia consists of a shaft or diaphysis, and two extremities or epiphyses.
So long as growth continues there intervenes between the shaft and each of the epiphyses a disc of actively growing cartilage the epiphysial cartilage; and at the junction of this cartilage with the shaft is a zone of young, vascular, spongy bone known as the metaphysis or epiphysial junction.
Conversely, excessive growth of bone at the ossifying junctions results in abnormal height of the skeleton or giantism as a result, for example, of increased activity of the pituitary in adolescents, and in eunuchs who have been castrated in childhood or adolescence; in the latter, union of the epiphyses at the ends of the long bones is delayed beyond the usual period at which the skeleton attains maturity.
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