synovium

WordNet

1. relating to or secreting synovia

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/29 05:03:39」(JST)

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Synovial membrane
Typical Joint
Synovial joint
Details
Latin	membrana synovialis capsulae articularis
Identifiers
Gray's	p.282
Dorlands /Elsevier	m_08/12522248
TA	A03.0.00.028
FMA	66762
Anatomical terminology

Synovial membrane (also known as synovium or stratum synoviale) is the soft tissue found between the articular capsule (joint capsule) and the joint cavity of synovial joints.

The word "synovium" is related to the word "synovia" (synovial fluid), which is the clear, viscous, lubricating fluid secreted by synovial membranes. The word "synvovia" or "sinovia" was coined by Paracelsus, and may have been derived from the Greek word "syn" ("with") and the Latin word "ovum" ("egg") because the synovial fluid in joints that have a cavity between the bearing surfaces is similar to egg white.

Structure

Synovium is very variable but often has two layers

• The outer layer, or subintima, can be of almost any type: fibrous, fatty or loosely "areolar".

• The inner layer, or intima, consists of a sheet of cells thinner than a piece of paper.

Where the underlying subintima is loose, the intima sits on a pliable membrane, giving rise to the term synovial membrane.

This membrane, together with the cells of the intima, provides something like an inner tube, sealing the synovial fluid from the surrounding tissue (effectively stopping the joints from being squeezed dry when subject to impact, such as running).

The surface of synovium may be flat or may be covered with finger-like projections or villi, which, it is presumed, help to allow the soft tissue to change shape as the joint surfaces move one on another.

Just beneath the intima, most synovium has a dense net of small blood vessels that provide nutrients not only for synovium but also for the avascular cartilage.

In any one position, much of the cartilage is close enough to get nutrition direct from synovium.

Some areas of cartilage have to obtain nutrients indirectly and may do so either from diffusion through cartilage or possibly by 'stirring' of synovial fluid.

The intimal cells are of two types, fibroblasts and macrophages, both of which are different in certain respects from similar cells in other tissues.

• The fibroblasts manufacture a long-chain sugar polymer called hyaluronan; which makes the synovial fluid "ropy"-like egg-white, together with a molecule called lubricin, which lubricates the joint surfaces. The water of synovial fluid is not secreted as such but is effectively trapped in the joint space by the hyaluronan.

• The macrophages are responsible for the removal of undesirable substances from the synovial fluid.

Synovial cell

Synovial cell	Resemble	Prominent organelle	Function
Type A	Macrophage	Mitochondria	Phagocytosis
Type B	Fibroblast	Endoplasmic reticulum	Secrete hyaluronic acid, & proteins complex (mucin) of synovial fluid

Mechanics

Although a biological joint can resemble a man-made joint in being a hinge or a ball and socket, the engineering problems that nature must solve are very different because the joint works within an almost completely solid structure, with no wheels or nuts and bolts.

In general, the bearing surfaces of manmade joints interlock, as in a hinge. This is rare for biological joints (although the badger's jaw interlocks).

More often the surfaces are held together by cord-like ligaments. Virtually all the space between muscles, ligaments, bones, and cartilage is filled with pliable solid tissue. The fluid-filled gap is at most only a twentieth of a millimetre thick. This means that synovium has certain rather unexpected jobs to do. These may include:

1. Providing a plane of separation, or disconnection, between solid tissues so that movement can occur with minimum bending of solid components. If this separation is lost, as in a 'frozen shoulder', the joint cannot move.
2. Providing a packing that can change shape in whatever way is needed to allow the bearing surfaces to move on each other.
3. Controlling the volume of fluid in the cavity so that it is just enough to allow the solid components to move over each other freely. This volume is normally so small that the joint is under slight suction.

Pathology

Synovium can become irritated and thickened in conditions such as synovitis or rheumatoid arthritis. When this happens, the synovium can become a danger to the bearing surface structure in a variety of ways. Excess synovial fluid weeping from inflamed synovium can provide a barrier to diffusion of nutrients to cartilage. The synovial cells may also use up nutrients so that the glucose level in the tissue is almost zero. These factors may lead to starvation and death of cartilage cells. Synovial cells may also produce enzymes that can digest the cartilage surface, although it is not clear that these will damage cartilage with healthy cells.

See also

• Synovial sheath

References

• Edwards JCW (2003). "Chapter 17". In Klippel, John H.; Hochberg, Marc C. Rheumatology. St. Louis: Mosby. pp. 159–68. ISBN 0-323-02404-1. 

UpToDate Contents

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• 1. 慢性関節リウマチにおける滑膜異常 synovial pathology in rheumatoid arthritis
• 2. 若年性特発性関節炎：疫学と免疫病態学 juvenile idiopathic arthritis epidemiology and immunopathogenesis
• 3. 研究用生物学的マーカーによる関節リウマチの診断および評価ま investigational biologic markers in the diagnosis and assessment of rheumatoid arthritis
• 4. 筋骨格系超音波検査：命名法、技術的な懸念、検証、および標準化 musculoskeletal ultrasonography nomenclature technical considerations validation and standardization
• 5. 関節リウマチの病因 pathogenesis of rheumatoid arthritis

English Journal

• Functional outcome measures in a surgical model of hip osteoarthritis in dogs.

• Little D1,2, Johnson S3, Hash J4, Olson SA3, Estes BT3,5, Moutos FT3,5, Lascelles BD4, Guilak F5,6.
• Journal of experimental orthopaedics.J Exp Orthop.2016 Dec;3(1):17. doi: 10.1186/s40634-016-0053-5. Epub 2016 Aug 15.
• BACKGROUND: The hip is one of the most common sites of osteoarthritis in the body, second only to the knee in prevalence. However, current animal models of hip osteoarthritis have not been assessed using many of the functional outcome measures used in orthopaedics, a characteristic that could increa
• PMID 27525982

• Differences in levels of inflammatory mediators in meniscal and synovial tissue of patients with meniscal lesions.

• Ogura T1, Suzuki M2, Sakuma Y3, Yamauchi K4, Orita S5, Miyagi M6, Ishikawa T7, Kamoda H8, Oikawa Y9, Kanisawa I10, Takahashi K11, Sakai H12, Nagamine T13, Fukuda H14, Takahashi K15, Ohtori S16, Tsuchiya A17.
• Journal of experimental orthopaedics.J Exp Orthop.2016 Dec;3(1):7. doi: 10.1186/s40634-016-0041-9. Epub 2016 Feb 3.
• BACKGROUND: Meniscal injuries are a risk factor for osteoarthritis (OA). While a mechanical pathway between meniscal injury and OA has been described, the biological effects of inflammation on this pathway have yet to be clarified. The aim of our study was to compare levels of specific inflammatory
• PMID 26915007

• It's not what it looks like: challenges in diagnosis of synovial lesions of the knee joint.

• Dash KK1, Gavai PV2, Wade R3, Rajani A4,5.
• Journal of experimental orthopaedics.J Exp Orthop.2016 Dec;3(1):5. doi: 10.1186/s40634-016-0039-3. Epub 2016 Jan 29.
• BACKGROUND: With the advent of MRI (Magnetic Resonance Imaging), Synovial lesions around knee are being more and more easily detected. Synovial lesions of knee present with boggy swelling, effusion, pain, and restriction of motion. Differential diagnoses of such lesions include pigmented villonodula
• PMID 26915005

Japanese Journal

• 滑膜幹細胞による軟骨・半月板を対象とした再生医療 (シンポジウム ヒト幹指針開始前・後から再生医療新法に至る整形外科領域の再生医療 : その進捗と今後の展望)

• 日本整形外科学会雑誌 91(4), 223-227, 2017-04
• NAID 40021199728

• The reduction and direct repair of isthmic spondylolisthesis using the smiley face rod method in adolescent athlete: Technical note

• The Journal of Medical Investigation 64(1.2), 168-172, 2017
• NAID 130005501973

• 臨床室 膝関節に発生した樹枝状脂肪腫の2例

• 整形外科 = Orthopedic surgery 67(11), 1158-1160, 2016-10
• NAID 40020967297

Related Links

• What Is Synovium? - Verywell - Know More. Feel Better.

The synovium, also referred to as the synovial membrane, is the soft tissue that lines the spaces of diarthrodial joints, tendon sheaths, and bursae. The synovium lines the entire inner surface of the joint, except where the ...

• Synovial pathology in rheumatoid arthritis

No single histologic feature or group of features in synovium is diagnostic of rheumatoid arthritis (RA). Many of the histologic changes that are seen can also occur in other inflammatory joint diseases and even in osteoarthritis. Thus ...

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★リンクテーブル★

リンク元	「synovial」

「synovial」

　　[★]

• adj.

• 滑膜の、滑液の

関

synovia、synovial fluid、synovial membrane、synovium