From the Guidelines
A growth plate is a specialized area of cartilage located near the ends of long bones in children and adolescents, consisting primarily of hyaline cartilage, where new bone tissue forms through endochondral ossification, and its relationship to cartilage is fundamental as it is made of cartilage but is temporary and designed to be replaced by bone. The growth plate serves as the site where cartilage cells (chondrocytes) multiply, enlarge, and eventually transform into bone, allowing bones to increase in length as a child grows 1. This cartilage-to-bone conversion occurs in an organized manner, with distinct zones of cell activity that maintain proper bone development. Growth plates remain open and active throughout childhood but close (ossify completely) during puberty when hormonal changes signal the end of bone lengthening.
Some key characteristics of growth plates include:
- They are located near the ends of long bones in children and adolescents
- They consist primarily of hyaline cartilage
- They serve as the site where new bone tissue forms through endochondral ossification
- They are temporary and designed to be replaced by bone
The relationship between growth plates and cartilage is crucial, as growth plate cartilage is temporary and designed to be replaced by bone, unlike permanent cartilage found in joints. Injuries to growth plates can be concerning because damage may disrupt normal bone growth, potentially leading to limb length discrepancies or angular deformities if not properly treated 1.
It's worth noting that growth plates play a critical role in bone development, and any disruptions to their function can have significant consequences for bone health and overall quality of life. Therefore, it's essential to prioritize the health and integrity of growth plates in children and adolescents to ensure proper bone development and minimize the risk of future complications 1.
From the Research
Definition of a Growth Plate
- A growth plate is an organ composed of cartilage, bone, and fibrous parts that work together to provide for longitudinal growth in long bones 2.
- It is made up of cartilaginous, bony, and fibrous components that act together to achieve longitudinal bone growth 3.
- The growth plate is a disk of hyaline cartilage interposed between the epiphysis and the metaphysis of each long bone, responsible for its elongation and increase in bodily height 4.
Relationship to Cartilage
- The growth plate consists solely of chondrocytes and an extracellular matrix, which the cells elaborate 4.
- Chondrocytes in the growth plate are aligned in strictly vertical columns, representing the functional units of longitudinal bone growth 4.
- The growth process begins with the slow division of chondrocytes in the resting zone and proceeds with their rapid proliferation in the adjacent zone, followed by progressive enlargement and terminal hypertrophy 4.
- The growth plate is an essential component of endochondral bone development, and its surrounding structure, the perichondrium, contains skeletal stem cells and progenitor cells that contribute to bone development 5.
- Chondrocytes and perichondrial cells develop from condensing undifferentiated mesenchymal cells during the fetal stage and ultimately serve to make bone bigger and stronger 5.
Function and Regulation
- The growth plate is regulated by various endocrine, paracrine, and autocrine agents, such as growth hormone, insulin-like growth factor-I (IGF-I), and vitamin D metabolites 6.
- Proliferation and differentiation of cartilage cells are regulated by these agents, and disorders in their metabolism or cellular responses can lead to deformities classified as dysplasias 6.
- The growth plate closes by an unknown mechanism during sexual maturation, and longitudinal bone growth ceases 6.