WordNet

with flat sails; "sail flat against the wind"
a deflated pneumatic tire (同)flat tire
a shallow box in which seedlings are started
scenery consisting of a wooden frame covered with painted canvas; part of a stage setting
a level tract of land; "the salt flats of Utah"
a musical notation indicating one half step lower than the note named
having a surface without slope, tilt in which no part is higher or lower than another; "a flat desk"; "acres of level farmland"; "a plane surface"; "skirts sewn with fine flat seams" (同)level, plane
not reflecting light; not glossy; "flat wall paint"; "a photograph with a matte finish" (同)mat, matt, matte, matted
sounded or spoken in a tone unvarying in pitch; "the owls faint monotonous hooting" (同)monotone, monotonic, monotonous
stretched out and lying at full length along the ground; "found himself lying flat on the floor" (同)prostrate
(of a musical note) lowered in pitch by one chromatic semitone; "B flat"
commercially inactive; "flat sales for the month"; "prices remained flat"; "a flat market"
having a relatively broad surface in relation to depth or thickness; "flat computer monitors"
having lost effervescence; "flat beer"; "a flat cola"
horizontally level; "a flat roof"
lacking contrast or shading between tones
remove the bones from; "bone the turkey before roasting it" (同)debone
the porous calcified substance from which bones are made (同)osseous_tissue
consisting of or made up of bone; "a bony substance"; "the bony framework of the body"
a shade of white the color of bleached bones (同)ivory, pearl, off-white
rigid connective tissue that makes up the skeleton of vertebrates (同)os
having bones as specified; "his lanky long-boned body"
having had the bones removed; "a boneless rib roast"; "a boned (or deboned) fish" (同)deboned
a percussion instrument consisting of a pair of hollow pieces of wood or bone (usually held between the thumb and fingers) that are made to click together (as by Spanish dancers) in rhythm with the dance (同)castanets, clappers, finger cymbals
footwear (shoes or slippers) with no heel (or a very low heel)

PrepTutorEJDIC

平『平らな』,平たんな / 《補語にのみ用いて》べったりと広がった(横になった) / 薄っぺらな(shallow) / 《名詞の前にのみ用いて》露骨な,あからさまな;(positive) / (料金・価格などが)均一(一律)の(uniform) / たいくつな,おもしろくない,気の抜けた / (発泡飲料が)気の抜けた / 空気のはいっていない,しぼんだ / (絵画で色調が)変化に乏しい,光沢を消した / (音楽で)変音の,半音下がった / 『きっぱりと』 / 正確に,きっかり / 本来の音程より下げて / 『平面』,平たい部分 / 平地,低地;《複数形で》湿地,沼地,浅瀬 / 枠張り物(舞台背景用のベニヤ・布などを張った枠組み) / 《おもに米》空気の抜けたタイヤ;パンク / 半音低い音,変音;変音記号
=apartment(同一階にある居間・食事部屋・台所・寝室などぐ含んだ住居)
〈C〉骨 / 〈U〉骨を作っている物質,骨質 / 《複数形で》骨格;死骸(がい) / 〈魚など〉‘の'骨を取る
(魚など)骨を取り除いた / (衣服が)(コルセットなどで)骨で張りをつけた[ような]

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/04/20 18:53:48」(JST)

wiki en

Flat bones are bones whose principal function is either extensive protection or the provision of broad surfaces for muscular attachment. These bones are expanded into broad, flat plates,^[1] as in the cranium (skull), the ilium (pelvis), sternum and the rib cage. The flat bones are: the occipital, parietal, frontal, nasal, lacrimal, vomer, hip bone (coxal bone), sternum, ribs, and scapulae.^[1] In the cranial bones, the layers of compact tissue are familiarly known as the tables of the skull; the outer one is thick and tough; the inner is thin, dense, and brittle, and hence is termed the vitreous (glass-like) table.^[1]

These bones are composed of two thin layers of compact bone enclosing between them a variable quantity of cancellous bone,^[1] which is the location of red bone marrow. In an adult, most red blood cells are formed in flat bones. The intervening cancellous tissue is called the diploë, and this, in the nasal region of the skull, becomes absorbed so as to leave spaces filled with air–the paranasal sinuses between the two tables.^[1]

Ossification in flat bones

Ossification is started by the formation of layers of undifferentiated connective tissue that hold the area where the flat bone is to come. On a baby, those spots are known as fontanelles. The fontanelles contain connective tissue stem cells, which form into osteoblasts, which secrete calcium phosphate into a matrix of canals. They form a ring in between the membranes, and begin to expand outwards. As they expand they make a bony matrix.

This hardened matrix forms the body of the bone. Since flat bones are usually thinner than the long bones, they only have red bone marrow, rather than both red and yellow bone marrow (yellow bone marrow being made up of mostly fat). The bone marrow fills the space in the ring of osteoblasts, and eventually fills the bony matrix.

After the bone is completely ossified, the osteoblasts retract their calcium phosphate secreting tendrils, leaving tiny canals in the bony matrix, known as canaliculi. These canaliculi provide the nutrients needed for the newly transformed osteoblasts, which are now called osteocytes. These cells are responsible for the general maintenance of the bone.

A third type of bone cell found in flat bones is called an osteoclast, which destroys the bone using enzymes. There are three reasons that osteoclasts are normally used: the first is for the reparation of bones after a break. They destroy sections of bone that protrude or make reformation difficult. They are also used to obtain necessary calcium from the bones. When a person's blood calcium is low, the osteoclasts take calcium from the bone and put it into the blood for necessary things such as nerve and muscle action. The last reason that osteoclasts are used is for growing. As the bone grows, its shape changes. The osteoclasts dissolve the part of the bone that must change.^[2]

Additional images

Flat bones in human skeleton. (shown in red)
Flat bones in human skull. (shown in red)
Classification of bones by shape.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

^ ^a ^b ^c ^d ^e Gray's Anatomy (1918). (See infobox)
^ Shier, David, Jackie Butler, and Ricki Lewis. "Chapter 7 Skeletal System." Hole's Human Anatomy & Physiology. 11th ed. Dubuque, IA: McGraw-Hill, 2007. 193+. Print.

UpToDate Contents

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1. 骨格の正常な発達および骨形成ならびに骨吸収の調節normal skeletal development and regulation of bone formation and resorption [show details]
…(cancellous) bone is found inside the long bones (particularly at the ends), throughout the bodies of the vertebrae, and in the inner portions of the pelvis and other large flat bones. Trabecular bone is an important …
2. 小児や青年の良性骨腫瘍nonmalignant bone lesions in children and adolescents [show details]
…fully characterize bone tumors in these locations . Radiographs should be reviewed systematically by considering the following questions : Where is the tumor? (Long bone or flat bone? Epiphysis, metaphysis …
3. 骨サルコイドーシスsarcoidosis of bone [show details]
…are associated with sarcoid of the flat bones. They may be observed with lesions of the nasal bones and hard palate; in the hands and feet, cystic or lytic underlying bone lesions may be present. Painless …
4. 腱滑膜巨細胞腫といった軟部組織や骨に影響を与えるさまざまな良性疾患への抗腫瘍療法antineoplastic therapy for miscellaneous benign diseases affecting soft tissue and bone including tenosynovial giant cell tumor [show details]
…involve skeletal muscle . When they arise in bone, the most frequently involved sites are the pelvic and other flat bones, the jawbones, and for the long bones, the diaphyseal regions. The tumors are often …
5. 骨系統疾患：評価アプローチskeletal dysplasias approach to evaluation [show details]
…which mesenchymal cells condense and directly develop into bone. Most flat bones of the skull, pelvis, and the terminal aspects of the clavicles develop through this process of membranous ossification. Endochondral …

English Journal

Effect of hormonal contraceptives on vitamin B12 level and the association of the latter with bone mineral density.

Berenson AB, Rahman M.SourceDepartment of Obstetrics and Gynecology and Center for Interdisciplinary Research in Women's Health, The University of Texas Medical Branch, Galveston, TX 77555, USA. Electronic address: abberens@utmb.edu.
Contraception.Contraception.2012 Nov;86(5):481-7. doi: 10.1016/j.contraception.2012.02.015. Epub 2012 Mar 28.
BACKGROUND: The study was conducted to estimate the effect of depot medroxyprogesterone acetate (DMPA) and oral contraceptives (OC) containing 20 mcg ethinyl estradiol on serum B12 and whether observed changes impact bone mineral density (BMD).STUDY DESIGN: Serum B12 and BMD at the lumbar spine and
PMID 22464408

Japanese Journal

Augmentation of Flat Bone Area Using Tetrapod-Shaped Artificial Bone in Rats

Iwata Jun,Namaki Shunsuke,Mashimo Takayuki [他]
Journal of hard tissue biology 24(1), 69-75, 2015-01
NAID 40020338413

Alignment of Biological Apatite Crystallites in Posterior Cortical Bone of Human Edentulous Mandible

Iwata Masayuki,Matsunaga Satoru,Morioka Toshiyuki,Nakano Takayoshi,Abe Shinichi,Yoshinari Masao,Yajima Yasutomo
Journal of Hard Tissue Biology 24(3), 235-240, 2015
… The mandible is a unique bone with a two-layered structure comprising the alveolar area that holds the teeth and the base of the mandible. … Quantitative assessment of changes in the bone microarchitecture that occur with tooth loss is thus imperative. … We therefore quantitatively assessed bone mineral density (BMD) and biological apatite (BAp) crystalline orientation in human edentulous mandibles and elucidated the structural characteristics of human edentulous mandibles. …
NAID 130005088088

Related Pictures

★リンクテーブル★

リンク元	「扁平骨」
関連記事	「flat」「bone」

「扁平骨」

Flat bone
	Anatomy of a flat bone (Frontal bone)
	Flat bones in human skeleton. (shown in red)
Details
Identifiers
Latin	os planum
Dorlands; /Elsevier	o_07/12598626
TA	A02.0.00.013
FMA	7476
	Anatomical terms of bone [edit on Wikidata]