Metaphysis

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Metaphysis
Structure of a Long Bone.png
Structure of a long bone, showing the metaphysis
Details
Pronunciation /mətˈæfɪsɪs/
Part of Long bones
Identifiers
Latin metaphysis
TA98 A02.0.00.022
TA2 392
FMA 24014
Anatomical terminology

The metaphysis (pl.: metaphyses) is the neck portion of a long bone between the epiphysis and the diaphysis. [1] It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses. The metaphysis contains a diverse population of cells including mesenchymal stem cells, which give rise to bone and fat cells, as well as hematopoietic stem cells which give rise to a variety of blood cells as well as bone-destroying cells called osteoclasts. Thus the metaphysis contains a highly metabolic set of tissues including trabecular (spongy) bone, blood vessels, as well as marrow adipose tissue (MAT).

Contents

The metaphysis may be divided anatomically into three components based on tissue content: a cartilaginous component (epiphyseal plate), a bony component (metaphysis) and a fibrous component surrounding the periphery of the plate. The growth plate synchronizes chondrogenesis with osteogenesis or interstitial cartilage growth with both appositional bone elongation in conjunction with growth in width, so bearing load and responding to local and systemic forces and factors balance one another mechanically.

During childhood, the growth plate contains the connecting cartilage enabling the bone to grow; at adulthood (between the ages of 18 and 25 years), the components of the growth plate stop growing altogether and completely ossify into solid bone. [2] In an adult, the metaphysis functions to transfer loads from weight-bearing joint surfaces to the diaphysis. [3]

Clinical significance

An X ray demonstrating the characteristic finding of lead poisoning in humans--dense metaphyseal lines. Lead PoisoningRadio.jpg
An X ray demonstrating the characteristic finding of lead poisoning in humans—dense metaphyseal lines.

Because of their rich blood supply and vascular stasis, metaphyses of long bones are prone to hematogenous spread of osteomyelitis in children. [4]

Metaphyseal tumors or lesions include osteosarcoma, chondrosarcoma, fibrosarcoma, osteoblastoma, enchondroma, fibrous dysplasia, simple bone cyst, aneurysmal bone cyst, non-ossifying fibroma, and osteoid osteoma. [5]

One of the clinical signs of rickets that doctors look for is cupping and fraying at the metaphyses when seen on X-ray.

See also

Related Research Articles

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<span class="mw-page-title-main">Mesoderm</span> Middle germ layer of embryonic development

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<span class="mw-page-title-main">Epiphysis</span> End of a long bone that ossifies from a secondary center

An epiphysis is one of the rounded ends or tips of a long bone that ossify from a secondary center of ossification. Between the epiphysis and diaphysis lies the metaphysis, including the epiphyseal plate. At the joint, the epiphysis is covered with articular cartilage; below that covering is a zone similar to the epiphyseal plate, known as subchondral bone. In evolution, reptiles do not have epiphyses and diaphyses, being restricted to mammals.

<span class="mw-page-title-main">Long bone</span> Bone that is longer than it is wide

The long bones are those that are longer than they are wide. They are one of five types of bones: long, short, flat, irregular and sesamoid. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. They grow primarily by elongation of the diaphysis, with an epiphysis at each end of the growing bone. The ends of epiphyses are covered with hyaline cartilage. The longitudinal growth of long bones is a result of endochondral ossification at the epiphyseal plate. Bone growth in length is stimulated by the production of growth hormone (GH), a secretion of the anterior lobe of the pituitary gland.

<span class="mw-page-title-main">Diaphysis</span> Shaft of a long bone, containing bone marrow

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<span class="mw-page-title-main">Ossification</span> Development process in bones

Ossification in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue (mesenchyme), while endochondral ossification involves cartilage as a precursor.

<span class="mw-page-title-main">Slipped capital femoral epiphysis</span> Medical condition

Slipped capital femoral epiphysis is a medical term referring to a fracture through the growth plate (physis), which results in slippage of the overlying end of the femur (metaphysis).

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<span class="mw-page-title-main">Epiphyseal plate</span> Cartilage plate in the neck of a long bone

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

<span class="mw-page-title-main">Ossification center</span> Point where ossification of the cartilage begins

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<span class="mw-page-title-main">Salter–Harris fracture</span> Medical condition

A Salter–Harris fracture is a fracture that involves the epiphyseal plate of a bone, specifically the zone of provisional calcification. It is thus a form of child bone fracture. It is a common injury found in children, occurring in 15% of childhood long bone fractures. This type of fracture and its classification system is named for Robert B. Salter and William H. Harris who created and published this classification system in the Journal of Bone and Joint Surgery in 1963.

<span class="mw-page-title-main">Chondroblastoma</span> Medical condition

Chondroblastoma is a rare, benign, locally aggressive bone tumor that typically affects the epiphyses or apophyses of long bones. It is thought to arise from an outgrowth of immature cartilage cells (chondroblasts) from secondary ossification centers, originating from the epiphyseal plate or some remnant of it.

<span class="mw-page-title-main">Fibrochondrogenesis</span> Medical condition

Fibrochondrogenesis is a rare autosomal recessive form of osteochondrodysplasia, causing abnormal fibrous development of cartilage and related tissues.

An epiphyseal line is an epiphyseal plate that has become ossified. The process of it forming from an epiphyseal plate is named epiphyseal closure. In adult humans, it marks the point of fusion between the epiphysis and the metaphysis.

The following outline is provided as an overview of and topical guide to trauma and orthopaedics:

References

  1. Dorland's Pocket Medical Dictionary, 27th edition
  2. Visual dictionary of Merriam-Webster
  3. "metaphysis". Encyclopædia Britannica.
  4. Luqmani, Raashid; Robb, James; Daniel, Porter; Benjamin, Joseph (2013). Orthopaedics, Trauma and Rheumatology (second ed.). Mosby. p. 96. ISBN   9780723436805.
  5. "New Jersey Medical School, Pathology Department Introductory Course on Bone Tumours". Archived from the original on 2009-03-06. Retrieved 2009-03-12.