![]() The nutrient artery provides four fifths of the metaphyseal blood supply. Perichondrial arteries supply the fibrous structures of the growth plate. Chondrocytes in the hypertrophic zone must use anaerobic glycolysis to furnish energy. No vessels penetrate beyond the proliferative zone and, therefore, the hypertrophic zone is relatively avascular. The multiple branches of the epiphyseal arteries arborize into the growth plate, providing vascularization to the first 4 to 10 cell columns of the proliferative zone. The arterial blood supply to the growth plate consists of branches of the vascular supply to the epiphysis and metaphysis ( Fig. Injury that results in disruption of or changes in the vascular networks may cause abnormal growth or cessation of growth. Vascular SupplyĪn intact vascular supply is necessary for cell proliferation and cartilage resorption and calcification, which are all necessary for growth, and for healing of fractures. Proteoglycans and water give resistance to pressure. Collagen fibers provide tension and shear resistance to the cartilage. Cell matrix, consisting of 70% water and 30% collagen fibrils, proteoglycans, and other noncollagenous proteins, is found as well. The major cell type of the growth plate is the chondrocyte. This is the portion of the metaphysis in which cartilage cells are transformed into bone. Immediately adjacent to the cartilaginous component is the bony component of the growth plate. ![]() The hypertrophic zone is the weakest part of the growth plate and is most commonly involved in Salter fractures. ![]() It is important to remember that damage to the reserve zone is associated with destruction of the germinal cells and, therefore, carries a high risk of resulting growth abnormalities. The hypertrophic zone is further divided into the zones of maturation, degeneration, and provisional calcification ( Fig. The cartilaginous component of the growth plate is divided into reserve (or germinal), proliferative, and hypertrophic zones. A biomechanical study in rabbits suggested that this structure protects growth cartilage from shear forces. The ring of LaCroix is located between the ossification groove and the periosteum of the metaphysis and provides mechanical support for the growth plate. The groove of Ranvier contributes chondrocytes for growth in both the diameter and length of the growth plate. The fibrous component surrounds the growth plate and is divided into an ossification groove, called the groove of Ranvier, and a perichondrial ring known as the ring of LaCroix. The growth plate consists of fibrous, cartilaginous, and bony components ( Fig. This chapter describes the basic anatomy of the growth plate, the relative contributions of the different growth plates to overall growth, the etiology and biomechanics of Salter fractures, and some diagnostic and prognostic guidelines. It is imperative to understand the physiology of the growth plate and the possible consequences of trauma in order to properly assess the severity of damage, give an appropriate prognosis, and provide the correct treatment. Today, these specific fractures involving the growth plate are commonly called “Salter Fractures.” Fractures of the growth plate may cause partial or complete arrest of growth, which may result in the loss of bone length and/or subsequent development of angular limb deformities and gait abnormalities. In 1963 Salter and Harris described a system of categorizing fractures involving the growth plate in relationship to the epiphyseal plate, the epiphysis, and the metaphysis ( Fig.
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