- Bone is the substance that forms the skeleton of the body. It is composed chiefly of calcium phosphate and calcium carbonate. It also serves as a storage area for calcium, playing a large role in calcium balance in the blood. The 206 bones in the body serve several other purposes. They support and protect internal organs (for example, the skull protects the brain and the ribs protect the lungs). Muscles pull against bones to make the body move. Bone marrow, the soft, spongy tissue in the center of many bones, makes and stores blood cells.
* * *A hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance and collagen fibers. The fibers are impregnated with a form of calcium phosphate similar to hydroxyapatite as well as with substantial quantities of carbonate, citrate sodium, and magnesium; by weight, b. is composed of 75% inorganic material and 25% organic material; a portion of osseous tissue of definite shape and size, forming a part of the animal skeleton; in humans there are 200 distinct bones in the skeleton, not including the auditory ossicles of the tympanic cavity or the sesamoid bones other than the two patellae. B. consists of a dense outer layer of compact substance or cortical substance covered by the periosteum, and an inner loose, spongy substance; the central portion of a long b. is filled with marrow. SYN: os [TA]. [A.S. ban]- alveolar b. 1. SYN: alveolar process of maxilla. 2. in dentistry, the specialized bony structure which supports the teeth; it consists of the cortical b. that comprises the tooth socket into which the roots of the tooth fit, and is supported by the trabecular b.. SYN: alveolar supporting b..- arm b. SYN: humerus.- basilar b. the developmental basilar process of the occipital b. that unites with the condylar portions in about the fourth or fifth year, becoming the basilar part of occipital b.. SEE ALSO: basilar part of occipital b.. SYN: basioccipital b., os basilare.- basisphenoid b. in comparative anatomy, the b. in the floor of the brain case in the region of the pituitary. See body of sphenoid.- blade b. SYN: scapula.- Breschet bones SYN: suprasternal bones.- brittle bones SYN: osteogenesis imperfecta.- bundle b. immature b. containing thick bundles of collagen fibers arranged nearly parallel to one another with osteocytes in between; a similar type of b. is found in regions penetrated by fibers of Sharpey, as at ligament and tendon attachments.- calcaneal b. SYN: calcaneus (1).- cancellous b. SYN: substantia spongiosa.- carpal bones [TA] eight bones arranged in two rows that articulate proximally with the radius and indirectly with the ulna, and distally with the five metacarpal bones; in domestic mammals, the bones of the proximal row are called radial, intermediate, ulnar, and accessory, while those of the distal row are termed first, second, third, and fourth carpal bones. SYN: carpus (2) [TA], ossa carpi [TA].- central b. SYN: os centrale.- compact b. [TA] the compact, noncancellous portion of b. that consists largely of concentric lamellar osteons and interstitial lamellae. SYN: substantia compacta [TA], compact substance, substantia compacta ossium.- convoluted b. inferior nasal concha, middle nasal concha, superior nasal concha, supreme nasal concha.- cortical b. [TA] the superficial thin layer of compact b.. SYN: substantia corticalis [TA], cortical substance.- coxal b. hip b..- bones of cranium [TA] the paired inferior nasal concha, lacrimal, maxilla, nasal, palatine, parietal, temporal, and zygomatic; and the unpaired ethmoid, frontal, occipital, sphenoid, and vomer. SYN: ossa cranii [TA], bones of skull, cranial bones.- cuboid (b.) the lateral b. of the distal row of the tarsus, articulating with the calcaneus, lateral cuneiform, navicular (occasionally), and fourth and fifth metatarsal bones. SYN: os cuboideum.- cuneiform b. triquetrum, intermediate cuneiform (b.), lateral cuneiform (b.), medial cuneiform (b.).- dorsal talonavicular b. an anomalous b. of the foot located near the head of the talus. SYN: Pirie b..- ear bones SYN: auditory ossicles, under ossicle.- endochondral b. a b. that develops in a cartilage environment after the latter is partially or entirely destroyed by calcification and subsequent resorption. SYN: cartilage b., replacement b..- epipteric b. a sutural b. occasionally present at the pterion or junction of the parietal, frontal, greater wing of the sphenoid, and squamous portion of the temporal bones. SYN: Flower b..- ethmoid b. [TA] an irregularly shaped b. lying between the orbital plates of the frontal and anterior to the sphenoid b.; it consists of two lateral masses of thin plates enclosing air cells, attached above to a perforated horizontal lamina, the cribriform plate, from which descends a median vertical or perpendicular plate in the interval between the two lateral masses; the b. articulates with the sphenoid, frontal, maxillary, lacrimal, and palatine bones, the inferior nasal concha, and the vomer; it enters into the formation of the anterior cranial fossa, the orbits, and the nasal cavity.- facial bones the bones surrounding the mouth and nose and contributing to the orbits; they are the paired maxillae, zygomatic, nasal, lacrimal, palatine, and inferior nasal conchae; and the unpaired ethmoid, vomer, mandible, and hyoid. SYN: bones of visceral cranium, ossa faciei.- flat b. [TA] a type of b. characterized by its thin, flattened shape, such as the scapula or certain of the cranial bones. SYN: os planum [TA].- bones of foot [TA] bones that collectively comprise the skeleton of the foot; includes tarsal bones, metatarsals (bones) [I–V], phalanges, and sesamoid bones. SYN: ossa pedis [TA], foot bones.- frontal b. [TA] the large single b. forming the forehead and the upper margin and roof of the orbit on either side; it articulates with the parietal, nasal, ethmoid, maxillary, and zygomatic bones, and with the lesser wings of the sphenoid. SYN: os frontale [TA], coronale (1).- funny b. colloquial name for tip of olecranon.- Goethe b. SYN: preinterparietal b..- hamate (b.) [TA] the b. on the medial (ulnar) side of the distal row of the carpus; it articulates with the fourth and fifth metacarpal, triquetral, lunate, and capitate. SYN: hamatum, hooked b., os hamatum, unciform b., unciforme, uncinatum.- heterotopic bones bones that do not belong to the main skeleton but that regularly develop in certain organs, e.g., the heart, penis, clitoris, and snout of some animals.- hip b. [TA] a large flat b. formed by the fusion of the ilium, ischium, and pubis (in the adult), constituting the lateral half of the pelvis; it articulates with its fellow anteriorly, with the sacrum posteriorly, and with the femur laterally. SYN: os coxae [TA], coxal b., pelvic b., innominate b., os innominatum.- hyoid b. 1. a U-shaped b. lying between the mandible and the larynx, suspended from the styloid processes by slender stylohyoid ligaments; 2. See hyoid apparatus. SYN: lingual b., os hyoideum, tongue b..- incarial b. SYN: interparietal b..- incisive b. [TA] the anterior and inner portion of the maxilla, which in the fetus and sometimes in the adult is a separate b.; the incisive suture runs from the incisive canal between the lateral incisor and the canine tooth; according to K. Albrecht, the incisive b. is further divided by a suture between the two incisor teeth on each side into two bones, the en dognathion and the mesognathion. SYN: os incisivum [TA], premaxilla (1) , intermaxilla, intermaxillary b., os intermaxillare, os premaxillare, premaxillary b..- innominate b. SYN: hip b..- intermediate cuneiform (b.) [TA] a b. of the distal row of the tarsus; it articulates with the medial and lateral cuneiform, navicular, and second metatarsal bones. SYN: mesocuneiform, middle cuneiform b., os cuneiforme intermedium, second cuneiform b., wedge b..- interparietal b. [TA] the upper part of the squama of the occipital b., developed in membrane instead of in cartilage as is the rest of the occipital, and occasionally (especially in ancient Peruvian skulls) existing as a separate b., separated from the remainder of the occipital by the sutura mendosa. SYN: os interparietale [TA], incarial b., os incae.- irregular b. [TA] one of a group of bones having peculiar or complex forms, e.g., vertebrae, many of the skull bones. SYN: os irregulare [TA].- jaw b. SYN: mandible.- Krause b. small b. (secondary ossification center) in the triradiate cartilage between the ilium, the ischium, and the pubic b. in the growing acetabulum.- lacrimal b. [TA] an irregularly rectangular thin plate, forming part of the medial wall of the orbit behind the frontal process of the maxilla; it articulates with the inferior nasal concha, ethmoid, frontal, and maxillary bones. SYN: os lacrimale [TA], os unguis.- lamellar b. the normal type of adult mammalian b., whether cancellous or compact, composed of parallel lamellae in the former and concentric lamellae in the latter; lamellar organization reflects a repeating pattern of collagen fibroarchitecture.- lateral cuneiform (b.) [TA] a b. of the distal row of the tarsus; it articulates with the intermediate cuneiform, cuboid, navicular, and second, third, and fourth metatarsal bones. SYN: os cuneiforme laterale [TA], third cuneiform b., wedge b..- long b. [TA] one of the elongated bones fof the extremities, consisting of a tubular shaft (diaphysis) and two extremities (epiphyses) usually wider than the shaft; the shaft is composed of compact b. surrounding a central medullary cavity. Cf.:short b.. SYN: os longum [TA], pipe b..- bones of lower limb [TA] these include the inferior limb girdle (hip b.) and the skeleton of the free inferior limb (femur, tibia, fibula, patella, tarsus, metatarsus, and bones of the toes). SYN: ossa membri inferioris [TA], bones of inferior limb.- lunate (b.) one of the proximal row in the carpus between the scaphoid and triquetral; it articulates with the radius, scaphoid, triquetral, hamate, and capitate. SYN: os lunatum [TA], lunare, os intermedium.- marble bones SYN: osteopetrosis.- medial cuneiform (b.) the largest of the three cuneiform bones, the medial b. of the distal row of the tarsus, articulating with the intermediate cuneiform, navicular, and first and second metatarsal bones. SYN: os cuneiforme mediale [TA], first cuneiform b., wedge b..- membrane b. a b. that develops embryologically within a membrane of vascularized primitive mesenchymal tissue without prior formation of cartilage.- mesethmoid b. in comparative anatomy, the b. present in some species as the most anterior b. of the floor of the braincase.- metacarpal (bones) [I–V] [TA] five long bones (numbered I to V, beginning with the b. on the radial or thumb side) forming the skeleton of the metacarpus or palm; they articulate with the bones of the distal row of the carpus and with the five proximal phalanges. SYN: ossa metacarpi [TA], ossa metacarpalia I–V.- metatarsal (bones) [I–V] the five long bones numbered I to V beginning with the b. on the medial side forming the skeleton of the anterior portion of the foot, articulating posteriorly with the three cuneiform and the cuboid bones, anteriorly with the five proximal phalanges. SYN: ossa metatarsi [TA], ossa metatarsalia I–V.- nasal b. [TA] an elongated rectangular b. which, with its fellow, forms the bridge of the nose; it articulates with the frontal b. superiorly, the ethmoid and the frontal process of the maxilla posteriorly, and its fellow medially. SYN: os nasale [TA].- nonlamellar b. SYN: woven b..- occipital b. [TA] a b. at the lower and posterior part of the skull, consisting of three parts (basilar, condylar, and squamous), enclosing a large oval hole, the foramen magnum; it articulates with the parietal and temporal bones on either side, the sphenoid anteriorly, and the atlas below. SYN: os occipitale [TA].- palatine b. [TA] an irregularly shaped b. posterior to the maxilla, which enters into the formation of the nasal cavity, the orbit, and the hard palate; it articulates with the maxilla, inferior nasal concha, sphenoid, and ethmoid bones, the vomer and its fellow of the opposite side. SYN: os palatinum [TA].- parietal b. [TA] a flat, curved b. of irregular quadrangular shape, at either side of the vault of the cranium; it articulates, with its fellow medially, with the frontal anteriorly, the occipital posteriorly, and the temporal and sphenoid inferiorly. SYN: os parietale [TA].- pelvic b. hip b..- perichondral b. in the development of a long b. a collar or cuff of osseous tissue forms in the perichondrium of the cartilage model; the connective tissue membrane of this perichondral b. then becomes periosteum. SYN: periosteal b..- periosteal b. SYN: perichondral b..- pipe b. SYN: long b..- pisiform (b.) a small b. resembling a pea in size and shape, in the proximal row of the carpus, lying on the anterior surface of the triquetral, with which it articulates; it gives insertion to the tendon of the flexor carpi ulnaris muscle. SYN: os pisiforme [TA], lentiform b..- pneumatized b. [TA] a b. that is hollow or contains many air cells, such as the mastoid process of the temporal b.. SYN: os pneumaticum [TA], hollow b., pneumatic b..- preinterparietal b. a large sutural b. occasionally found detached from the anterior portion of the os interparietale. SYN: Goethe b..- presphenoid b. in comparative anatomy, the b. in the floor of the brain case anterior to the basisphenoid b..- reticulated b. SYN: woven b..- rider's b. heterotopic b. ossification of the tendon of the adductor longus muscle from strain in horseback riding.- sacred b. SYN: sacrum. [so-called from belief in indestructibility of the b. as the basis for resurrection]- scaphoid (b.) the largest b. of the proximal row of the carpus on the lateral (radial) side, articulating with the radius, lunate, capitate, trapezium, and trapezoid. SYN: os scaphoideum [TA], navicular b. of hand, os naviculare manus.- scroll bones inferior nasal concha, middle nasal concha, superior nasal concha, supreme nasal concha.- sesamoid b. [TA] a b. formed after birth in a tendon where it passes over a joint, e.g., the patella. SYN: os sesamoideum [TA].- short b. [TA] one whose dimensions are approximately equal; it consists of a layer of cortical substance enclosing spongy substance and marrow. Cf.:long b.. SYN: os breve [TA].- b. sialoprotein 1 SYN: osteopontin.- sphenoid (b.) a b. of most irregular shape occupying the base of the skull; it is described as consisting of a central portion, or body, and six processes: two greater wings, two lesser wings and two pterygoid processes; it articulates with the occipital, frontal, ethmoid, and vomer, and with the paired temporal, parietal, zygomatic, palatine, and sphenoidal concha bones. SYN: os sphenoidale [TA], sphenoid (2) [TA].- suprasternal bones [TA] one of the small ossicles occasionally found in the ligaments of the sternoclavicular articulation. SYN: ossa suprasternalia [TA], Breschet bones, episternal b..- sutural bones [TA] small irregular bones found along the sutures of the cranium, particularly related to the parietal b.. SYN: os suturarum [TA], Andernach ossicles, epactal bones, epactal ossicles, wormian bones.- tarsal bones [TA] the seven bones of the instep : talus, calcaneus, navicular, three cuneiform (wedge), and cuboid bones. SYN: ossa tarsi [TA], tarsale [TA], ossa tarsalia.- temporal b. [TA] a large irregular b. situated in the base and side of the skull; it consists of three parts, squamous, tympanic, and petrous, which are distinct at birth; the petrous part contains the vestibulocochlear organ; the b. articulates with the sphenoid, parietal, occipital, and zygomatic bones, and by a synovial joint with the mandible. SYN: os temporale [TA].- three-cornered b. SYN: triquetrum.- trabecular b. substantia spongiosa.- trapezium b. the lateral (radial) b. in the distal row of the carpus; it articulates with the first and second metacarpals, scaphoid, and trapezoid bones. SYN: greater multangular b., os multangulum majus, os trapezium, trapezium (2).- trapezoid (b.) a b. in the distal row of the carpus; it articulates with the second metacarpal, trapezium, capitate, and scaphoid. SYN: os trapezoideum [TA], trapezoid (3) [TA], lesser multangular b., os multangulum minus.- turbinated bones inferior nasal concha, middle nasal concha, superior nasal concha, supreme nasal concha.- tympanohyal b. a small nodule of b. forming the base of the cartilaginous styloid process of the temporal b. at birth.- upper jaw b. SYN: maxilla.- bones of upper limb [TA] these include the superior limb girdle (scapula and clavicle) and the skeleton of the free superior limb (humerus, radius, ulna, wrist bones, metacarpus, and bones of the fingers). SYN: ossa membri superioris [TA], bones of superior limb.- woven b. bony tissue characteristic of the embryonal skeleton, in which the collagen fibers of the matrix are arranged irregularly in the form of interlacing networks. SYN: nonlamellar b., reticulated b..- zygomatic b. [TA] a quadrilateral b. that forms the prominence of the cheek; it articulates with the frontal, sphenoid, temporal, and maxillary bones. SYN: os zygomaticum [TA], cheek b. (1), jugal b., mala (2), malar b., os malare, yoke b., zygoma (1).
* * *bone 'bōn n, often attrib1) one of the hard parts of the skeleton of a vertebrate <a shoulder \bone> <the \bones of the arm>2) any of various hard animal substances or structures (as baleen or ivory) akin to or resembling bone3) the hard largely calcareous connective tissue of which the adult skeleton of most vertebrates is chiefly composed <cancellous \bone> <compact \bone> compare CARTILAGE (1)
* * *n.the hard extremely dense connective tissue that forms the skeleton of the body. It is composed of a matrix of collagen fibres impregnated with bone salts (chiefly calcium carbonate and calcium phosphate; see hydroxyapatite), in which are embedded bone cells (see osteocyte). Compact (or cortical) bone forms the outer shell of bones; it consists of a hard virtually solid mass made up of bony tissue arranged in concentric layers (Haversian systems). Spongy (or cancellous) bone, found beneath compact bone, consists of a meshwork of bony bars (<
) with many interconnecting spaces containing marrow.Individual bones may be classed as long, short, flat, or irregular. The outer layer of a bone is called the periosteum. The medullary cavity is lined with endosteum and contains the marrow. Bones not only form the skeleton but also act as stores for mineral salts and play an important part in the formation of blood cells.
* * *(bōn) [L. os; Gr. osteon] 1. the hard form of connective tissue that constitutes the majority of the skeleton of most vertebrates; it consists of an organic component (the cells and matrix) and an inorganic, or mineral, component; the matrix contains a framework of collagenous fibers and is impregnated with the mineral component, chiefly calcium phosphate (85 per cent) and calcium carbonate (10 per cent), which imparts the quality of rigidity to bone. Called also osseous tissue. 2. any distinct piece of the osseous framework, or skeleton, of the body; called also os. See Plates 8 and 40.
PLATE 8 STRUCTURE, VASCULARIZATION, AND DEVELOPMENT OF BONE
Medical dictionary. 2011.