Epiphyseal plate

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Epiphyseal plate_table_infobox_0

Epiphyseal plateEpiphyseal plate_header_cell_0_0_0
DetailsEpiphyseal plate_header_cell_0_1_0
IdentifiersEpiphyseal plate_header_cell_0_2_0
LatinEpiphyseal plate_header_cell_0_3_0 lamina epiphysialisEpiphyseal plate_cell_0_3_1
MeSHEpiphyseal plate_header_cell_0_4_0 Epiphyseal plate_cell_0_4_1
TA98Epiphyseal plate_header_cell_0_5_0 Epiphyseal plate_cell_0_5_1
TA2Epiphyseal plate_header_cell_0_6_0 Epiphyseal plate_cell_0_6_1
FMAEpiphyseal plate_header_cell_0_7_0 Epiphyseal plate_cell_0_7_1

This article uses anatomical terminology. Epiphyseal plate_sentence_0

The epiphyseal plate (or epiphysial plate, physis, or growth plate) is a hyaline cartilage plate in the metaphysis at each end of a long bone. Epiphyseal plate_sentence_1

It is the part of a long bone where new bone growth takes place; that is, the whole bone is alive, with maintenance remodeling throughout its existing bone tissue, but the growth plate is the place where the long bone grows longer (adds length). Epiphyseal plate_sentence_2

The plate is only found in children and adolescents; in adults, who have stopped growing, the plate is replaced by an epiphyseal line. Epiphyseal plate_sentence_3

This replacement is known as epiphyseal closure or growth plate fusion. Epiphyseal plate_sentence_4

Complete fusion happens on average between ages 12–18 for girls (with the most common being 15-16 years for girls) and 14–19 for boys (with the most common being 18-20 years for boys). Epiphyseal plate_sentence_5

Structure Epiphyseal plate_section_0

Development Epiphyseal plate_section_1

Endochondral ossification is responsible for the initial bone development from cartilage in utero and infants and the longitudinal growth of long bones in the epiphyseal plate. Epiphyseal plate_sentence_6

The plate's chondrocytes are under constant division by mitosis. Epiphyseal plate_sentence_7

These daughter cells stack facing the epiphysis while the older cells are pushed towards the diaphysis. Epiphyseal plate_sentence_8

As the older chondrocytes degenerate, osteoblasts ossify the remains to form new bone. Epiphyseal plate_sentence_9

In puberty increasing levels of estrogen, in both females and males, leads to increased apoptosis of chondrocytes in the epiphyseal plate. Epiphyseal plate_sentence_10

Depletion of chondrocytes due to apoptosis leads to less ossification and growth slows down and later stops when the entire cartilage have become replaced by bone, leaving only a thin epiphyseal scar which later disappears. Epiphyseal plate_sentence_11

Histology Epiphyseal plate_section_2

The growth plate has a very specific morphology in having a zonal arrangement as follows: Epiphyseal plate_sentence_12

Epiphyseal plate_table_general_1

Epiphyseal plate zone (from epiphysis to diaphysis)Epiphyseal plate_header_cell_1_0_0 DescriptionEpiphyseal plate_header_cell_1_0_1
Zone of reserveEpiphyseal plate_cell_1_1_0 Quiescent chondrocytes are found at the epiphyseal endEpiphyseal plate_cell_1_1_1
Zone of proliferationEpiphyseal plate_cell_1_2_0 Chondrocytes undergo rapid mitosis under influence of growth hormoneEpiphyseal plate_cell_1_2_1
Zone of maturation and hypertrophyEpiphyseal plate_cell_1_3_0 Chondrocytes stop mitosis, and begin to hypertrophy by accumulating glycogen, lipids, and alkaline phosphataseEpiphyseal plate_cell_1_3_1
Zone of calcificationEpiphyseal plate_cell_1_4_0 Chondrocytes undergo apoptosis. Cartilagenous matrix begins to calcify.Epiphyseal plate_cell_1_4_1
Zone of ossificationEpiphyseal plate_cell_1_5_0 Osteoclasts and osteoblasts from the diaphyseal side break down the calcified cartilage and replace with mineralized bone tissue.Epiphyseal plate_cell_1_5_1

Clinical significance Epiphyseal plate_section_3

Defects in the development and continued division of epiphyseal plates can lead to growth disorders collectively known as osteochondrodysplasia. Epiphyseal plate_sentence_13

The most common defect is achondroplasia, where there is a defect in cartilage formation. Epiphyseal plate_sentence_14

Achondroplasia is the most common cause of dwarfism or short stature and it also manifests in generalized deformities of bones and joints. Epiphyseal plate_sentence_15

However, various other types of osteochondrodysplasias can cause short stature and generalized deformities of bones and joints due to abnormal function of growth plate cartilage cells. Epiphyseal plate_sentence_16

Hereditary multiple exostoses is a genetic condition that is caused by growth irregularities of the epiphyseal plates of the long bones of the upper and lower limbs. Epiphyseal plate_sentence_17

It usually results in limb deformities and a certain degree of functional limitations. Epiphyseal plate_sentence_18

Salter–Harris fractures are fractures involving epiphyseal plates and hence tend to interfere with growth, height or physiologic functions. Epiphyseal plate_sentence_19

Osgood-Schlatter disease results from stress on the epiphyseal plate in the tibia, leading to excess bone growth and a painful lump at the knee. Epiphyseal plate_sentence_20

There are important clinical implications of the growth plate physiology. Epiphyseal plate_sentence_21

For example guided growth surgery, also known as temporary hemiepiphysiodesis is used to achieve correction or straightening of the bone deformities in a variety of pediatric orthopedic disorders such as Blount's disease, rickets, arthrogryposis multiplex congenita and osteochondrodysplasias among others. Epiphyseal plate_sentence_22

This applies to bone and joint deformities in the coronal –medial/lateral- plane or genu varum/genu valgum plane and in the sagittal –anterior/posterior- plane or knee flexion deformity/ genu recurvatum plane. Epiphyseal plate_sentence_23

Other animals Epiphyseal plate_section_4

John Hunter studied growing chickens. Epiphyseal plate_sentence_24

He observed bones grew at the ends and thus demonstrated the existence of the epiphyseal plates. Epiphyseal plate_sentence_25

Hunter is considered the "father of the growth plate." Epiphyseal plate_sentence_26

See also Epiphyseal plate_section_5

Epiphyseal plate_unordered_list_0

Credits to the contents of this page go to the authors of the corresponding Wikipedia page: en.wikipedia.org/wiki/Epiphyseal plate.