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Medical Dictionary


osteologist (os′te-ol′o-jist)
A specialist in osteology.

osteology (os′te-ol′o-je)
The anatomy of the bones; the science concerned with the bones and their structure. SYN: osteologia. [osteo- + G. logos, study]

osteolysis (os-te-ol′i-sis)
Softening, absorption, and destruction of bony tissue, a function of the osteoclasts. [osteo- + G. lysis, dissolution]

osteolytic (os-te-o-lit′ik)
Pertaining to, characterized by, or causing osteolysis.

osteoma (os-te-o′ma)
A benign, slow-growing mass of mature, predominantly lamellar bone, usually arising from the skull or mandible. [osteo- + G. -oma, tumor] o. cutis cutaneous ossification usually secondary to calcification in foci of degeneration in tumors or inflammatory lesions or, rarely, primary new bone formation in normal skin, often associated with Albright hereditary ostrodystrophy. dental o. an exostosis arising from the root of a tooth. giant osteoid o. SYN: osteoblastoma. o. medullare an o. containing spaces that are filled (or partly filled) with various elements of bone marrow. osteoid o. a painful benign neoplasm that usually originates in one of the bones of the lower extremities, especially the femur or tibia of adolescent and young adult persons; characterized by a nidus (usually no larger than 1 cm in diameter) that consists of osteoid material, vascularized osteogenic stroma, and poorly formed bone; around the nidus there is a relatively large zone of reactive thickening of the cortex. o. spongiosum an o. that consists chiefly of cancellous bone tissue.

osteomalacia (os′te-o-ma-la′she-a)
A disease characterized by a gradual softening and bending of the bones with varying severity of pain; softening occurs because the bones contain osteoid tissue that has failed to calcify because of lack of vitamin D or renal tubular dysfunction; more common in women than in men, o. often begins during pregnancy. SYN: adult rickets, late rickets, rachitis tarda. [osteo- + G. malakia, softness] infantile o., juvenile o. SYN: rickets. senile o. osteoporosis in the aged.

osteomalacic (os′te-o-ma-la′sik)
Relating to, or suffering from, osteomalacia.

osteomatoid (os-te-o′ma-toyd)
An abnormal nodule or small mass of overgrowth of bone, usually occurring bilaterally and symmetrically, in juxtaepiphysial regions, especially in long bones of the lower extremities; lesions are not actually neoplasms, but represent anomalous developments in which there are outpouchings of the cortex (in contrast to a growth superimposed on the cortex), and are more properly termed exostoses. [osteoma + G. eidos, appearance, form]

osteomere (os′te-o-mer)
One of the series of bone segments, such as the vertebrae. [osteo- + G. meros, a part]

osteometry (os-te-om′e-tre)
The branch of anthropometry concerned with the relative size of the different parts of the skeleton. [osteo- + G. metron, measurement]

osteomyelitis (os′te-o-mi-e-li′tis)
Inflammation of the bone marrow and adjacent bone. SYN: central osteitis (1) . [osteo- + G. myelos, marrow, + -itis, inflammation] chronic diffuse sclerosing o. a proliferative reaction of bone to a low-grade infection of the jaws; most often seen in middle-aged or older black women as extensive, often bilateral radio-opacities of the mandible and maxilla. chronic focal sclerosing o. a reaction of bone to a mild bacterial infection, often the result of a carious tooth, in persons with a high degree of tissue resistance; results in a localized radio-opacity. SYN: focal condensing osteitis. Garré o. chronic o. with proliferative periostitis. A focal gross thickening of the periosteum with peripheral reactive bone formation resulting from mild infection. Pseudomonas o. SYN: malignant external otitis.

osteomyelodysplasia (os′te-o-mi′e-lo-dis-pla′-ze-a)
A disease characterized by enlargement of the marrow cavities of the bones, thinning of the osseous tissue, large, thin-walled vascular spaces, leukopenia, and irregular fever. [osteo- + G. myelos, marrow, + dysplasia]

osteon, osteone (os′te-on, -on)
A central canal containing blood capillaries and the concentric osseous lamellae around it occurring in compact bone. SYN: haversian system. [G. o., bone]

osteoncus (os-te-ong′kus)
An osteoma, sometimes used with reference to any neoplasm of a bone. [osteo- + G. onkos, bulk (swelling)]

osteonecrosis (os′te-o-ne-kro′sis)
The death of bone in mass, as distinguished from caries (“molecular death”) or relatively small foci of necrosis in bone. [osteo- + G. nekrosis, death]

A protein (MW 39,000–40,000) found in bone and nonmineralized tissues and believed to play a role in mineralization.

osteopath (os′te-o-path)
SYN: osteopathic physician.

osteopathia (os′te-o-path′e-a)
SYN: osteopathy (1) . o. condensans SYN: osteopoikilosis. o. hemorrhagica infantum SYN: infantile scurvy. o. striata linear striations seen radiographically in the metaphyses of long bones and also flat bones; it may be a variant of osteopoikilosis. SYN: Voorhoeve disease.

osteopathic (os-te-o-path′ik)
Relating to osteopathy.

osteopathology (os′te-o-pa-thol′o-je)
Study of diseases of bone.

osteopathy (os-te-op′a-the)
1. Any disease of bone. SYN: osteopathia. 2. A school of medicine based upon a concept of the normal body as a vital machine capable, when in correct adjustment, of making its own remedies against infections and other toxic conditions; practitioners use the diagnostic and therapeutic measures of conventional medicine in addition to manipulative measures. SYN: osteopathic medicine. [osteo- + G. pathos, suffering] alimentary o. bone disease due to dietary deficiency.

osteopedion (os′te-o-pe′de-on)
Obsolete term for lithopedion. [osteo- + G. paidion, dim. of pais, a child]

osteopenia (os′te-o-pe′ne-a)
1. Decreased calcification or density of bone; a descriptive term applicable to all skeletal systems in which such a condition is noted; carries no implication about causality. 2. Reduced bone mass due to inadequate osteoid synthesis. [osteo- + G. penia, poverty]

osteoperiostitis (os′te-o-per′e-os-ti′tis)
Inflammation of the periosteum and of the underlying bone.

osteopetrosis (os′te-o-pe-tro′sis) [MIM*166600]
Excessive formation of dense trabecular bone and calcified cartilage, especially in long bones, leading to obliteration of marrow spaces and to anemia with myeloid metaplasia and hepatosplenomegaly beginning in infancy, to bone fragility, and to progressive deafness and blindness; autosomal dominant inheritance. There are also autosomal recessive forms, which may be mild [MIM*259710], severe [MIM*259700], or lethal [MIM*259720], and sometimes involve a renal tubular defect [MIM*259730]. A milder, autosomal dominant form has onset in childhood and no neurologic sequelae. SYN: Albers-Schönberg disease, marble bone disease, marble bones. [osteo- + G. petra, stone, + -osis, condition] o. acro-osteolytica SYN: pyknodysostosis. o. with renal tubular acidosis SYN: carbonic anhydrase II deficiency syndrome.

osteopetrotic (os′te-o-pe-trot′ik)
Relating to osteopetrosis.

osteophage (os′te-o-faj)
SYN: osteoclast (1) . [osteo- + G. phago, to eat]

osteophlebitis (os′te-o-fle-bi′tis)
Inflammation of the veins of a bone. [osteo- + G. phleps, vein, + -itis, inflammation]

osteophony (os′te-of′o-ne)
SYN: bone conduction.

osteophyte (os′te-o-fit)
A bony outgrowth or protuberance. [osteo- + G. phyton, plant]

osteoplaque (os′te-o-plak)
Any osseous layer. [osteo- + Fr. plaque, plate]

osteoplast (os′te-o-plast)
SYN: osteoblast. [osteo- + G. plastos, formed]

osteoplastic (os-te-o-plas′tik)
1. SYN: osteogenic. 2. Relating to osteoplasty.

osteoplasty (os′te-o-plas-te)
1. Bone grafting; reparative or plastic surgery of bones. 2. In dentistry, resection of osseous structure to achieve acceptable gingival contour. [osteo- + G. plastos, formed]

osteopoikilosis (os′te-o-poy-ki-lo′sis)
Mottled or spotted bones caused by widespread small foci of compact bone in the substantia spongiosa; autosomal dominant inheritance [MIM*166700]. SEE ALSO: osteopathia striata, dermatofibrosis lenticularis disseminata. SYN: osteopathia condensans. [osteo- + G. poikilos, dappled, + -osis, condition]

A protein produced by osteoblasts of unknown function.

A secreted phosphoprotein, produced by many epithelial cell types, that is highly negatively charged and frequently associated with mineralization processes. It is found in plasma, urine, milk, and bile. Transformed cells express o. in elevated levels. SYN: bone sialoprotein 1.

osteoporosis (os′te-o-po-ro′sis)
Reduction in the quantity of bone or atrophy of skeletal tissue; an age-related disorder characterized by decreased bone mass and increased susceptibility to fractures. [osteo- + G. poros, pore, + -osis, condition] O. affects 20 million Americans, about 80% of them women, and costs U.S. society as much as $3.8 billion annually. About 1.3 million fractures attributable to o. occur each year in people age 45 and older, and this condition is responsible for 50% of fractures occurring in women over age 50. Although all bones are affected, compression fractures of the vertebrae and traumatic fractures of the wrist and femoral neck are most common. Gradual asymptomatic vertebral compression may be detectable only on radiographic examination. Loss of body height and development of kyphosis may be the only signs of vertebral collapse. After hip fracture, most elderly patients fail to recover normal activity, and mortality within 1 year approaches 20%. Fractures in the elderly often lead to loss of mobility and independence, social alienation, fear of further falls and fractures, and depression. O. occurs when bone resorption outpaces bone formation. Mechanisms underlying o. are complex and probably diverse. Bone constantly undergoes cycles of resorption and formation (remodeling) to maintain the concentration of calcium and phosphate in the extracellular fluid. When serum calcium concentration drops, parathyroid hormone secretion increases, and this hormone stimulates bone resorption by osteoclasts to restore serum calcium levels to normal. Bone mass declines with age and is influenced by sex, race, menopause, and body weight-for-height. Dietary intake of calcium and vitamin D as well as intestinal and renal function affect calcium and phosphate homeostasis. The risk of o. is highest in postmenopausal women. Asian or white race, underweight, dietary calcium deficiency, sedentary lifestyle, alcohol use, and cigarette smoking appear to be independent risk factors. The decline of vitamin D3 level with aging results in calcium malabsorption, which, in turn, stimulates bone resorption. Estrogen deficiency exacerbates this problem by increasing the sensitivity of bone to resorbing agents. Women who become amenorrheic because of rigorous athletic exercise and dietary restriction or eating disorders are at risk of o.. The formation and resorption of bone are also influenced by external physical factors such as body weight and exercise. Immobilization and prolonged bed rest produce rapid bone loss, while exercise involving weight-bearing has been shown both to reduce bone loss and to increase bone mass. O. is common in young adults with cystic fibrosis, particularly those treated with long-term corticosteroid therapy. The diagnosis of primary o. is established by documentation of reduced bone density after exclusion of known causes of excessive bone loss. Radiographs are insensitive indicators of bone loss, since bone density must be decreased by at least 20–30% before the reduction can be appreciated. Standard diagnostic procedures are determination of bone mineral density at the ultradistal radius and midshaft radius by single-photon absorptiometry, and at the hip and lumbar spine by dual-energy x-ray absorptiometry (DEXA). A quantitative ultrasound procedure recently approved by the FDA is comparable to bone density measurements by DEXA in predicting fractures due to o.. The goal of therapy in o. is prevention of fractures in susceptible patients. The appropriate timing and proper use of agents such as calcium, vitamin D, estrogen, bisphosphonates, calcitonin, and raloxifene and the role of exercise have generated major research efforts and considerable controversy. Intake of adequate amounts of calcium and vitamin D, and continuing moderate weight-bearing exercise, are basic preventive measures for persons of all ages. Administration of estrogen at and after menopause does not simply halt the loss of bone, but actually increases bone mass. Hormone replacement with estrogen remains the most effective prevention and treatment for postmenopausal o.. It is believed to be most appropriate to start estrogen at the earliest sign of the menopause, since bone loss probably begins before the cessation of menses. Estrogen therapy must be continued through later life to maintain optimal bone density. There is no convincing evidence that initiating estrogen therapy in elderly women will prevent o.. The benefits of estrogen therapy must be weighed against the increased risk of endometrial hyperplasia and endometrial carcinoma (which can be offset by concomitant administration of progestogen) and possibly of carcinoma of the breast. The selective estrogen receptor modulator raloxifene has been approved for prevention of o.. It does not cause endometrial hyperplasia but is less effective than estrogen in conserving bone mass. The hormone calcitonin, administered by injection or nasal spray, inhibits bone resorption and has other effects on mineral metabolism. Bisphosphonates such as alendronate and etidronate, which bind to bone crystals, rendering them resistant to enzymatic hydrolysis and inhibiting the action of osteoclasts, have been shown to increase bone mineral density. Strategies to prevent falls are important in elderly patients. see also estrogen replacement therapy, raloxifene. o. circumscripta cranii localized cranial o. often seen in Paget disease. juvenile o. idiopathic o. with onset before puberty, leading to pain or fractures, with spontaneous remission within a few years. posttraumatic o. SYN: Sudeck atrophy.

osteoporotic (os′te-o-po-rot′ik)
Pertaining to, characterized by, or causing a porous condition of the bones.

osteoprotegerin (os′te-o-pro-teg′er-in)
A secreted protein that inhibits osteoclast differentiation.

osteoradiologist (os′te-o-ra-de-ol′o-jist)
A physician who specializes in radiology of the bones and joints. [osteo- + radiologist]

The clinical subspecialty of diagnostic bone radiology.

osteoradionecrosis (os′te-o-ra′de-o-ne-kro′sis)
Necrosis of bone produced by ionizing radiation; may be planned or unplanned. [osteo- + radionecrosis]

osteorrhaphy (os-te-or′a-fe)
Wiring together the fragments of a broken bone. SYN: osteosuture. [osteo- + G. rhaphe, suture]

osteosarcoma (os′te-o-sar-ko′ma)
SYN: osteogenic sarcoma. parosteal o. low-grade o. arising on the surface of bone without involvement of the underlying marrow, usually occurring as a heavily ossified mass of the distal femur in women in the third and fourth decades of life. periosteal o. chondroblastic o. occurring on the surface of bones without involvement of the marrow; usually presents in adolescents and young adults as a lucent defect with bone spicules extending into soft tissues. Histologically, the tumor is intermediate to high grade, and the cartilage is lobulated.

osteosclerosis (os′te-o-skle-ro′sis)
Abnormal hardening or eburnation of bone. [osteo- + G. sklerosis, hardness]

osteosclerotic (os′te-o-skle-rot′ik)
Relating to, due to, or marked by hardening of bone substance.

osteosis (os-te-o′sis)
1. A morbid process in bone. SYN: ostosis (1) . 2. SYN: osteogenesis. [osteo- + G. -osis, condition] parathyroid o. SYN: osteitis fibrosa cystica. renal fibrocystic o. SYN: renal rickets.

osteospongioma (os′te-o-spon′je-o′ma)
General nonspecific term for a neoplasm in bone that results in thinning and fragmentation (thus, in softening) of the cortex. [osteo- + G. spongos, sponge, + -oma, tumor]

osteosteatoma (os′te-o-ste′a-to′ma)
A benign mass, usually a lipoma or sebaceous cyst, in which small foci of bony elements are present. [osteo- + G. stear, suet, fat, + -oma, tumor]

osteosuture (os-te-o-soo′choor)
SYN: osteorrhaphy.

osteosynthesis (os-te-o-sin′the-sis)
Internal fixation of a fracture by means of a mechanical device, such as a pin, screw, or plate.

osteothrombosis (os′te-o-throm-bo′sis)
Thrombosis in one or more of the veins of a bone.

osteotome (os′te-o-tom)
An instrument for use in cutting bone. [osteo- + G. tome, incision]

osteotomy (os-te-ot′o-me)
Cutting a bone, usually by means of a saw or osteotome. [osteo- + G. tome, incision] “C” sliding o. an extraoral o. in the shape of a “C” performed bilaterally in the mandibular rami for the correction of retrognathia and/or apertognathia. Dwyer o. a procedure for clubfoot. horizontal o. an o. performed intraorally for genioplasty; the inferior aspect of the anterior mandible is advanced or retruded by movement of the free segment. Le Fort o. an o. performed along the classic lines of fracture as described by Le Fort to correct a maxillary skeletal deformity; classified as Le Fort o. I, lower maxillary; II, pyramidal nasoorbitomaxillary; or III, high maxillary, depending upon the location. sagittal split mandibular o. an intraoral surgical procedure for correction of retrognathism, apertognathia, and prognathism; the mandibular rami and posterior body are sectioned in the sagittal plane. segmental alveolar o. an intraoral surgical procedure in which segments of alveolar bone containing teeth are sectioned between, and apically to, the teeth for the repositioning of the alveolus and teeth; it may be maxillary or mandibular, and may be combined with ostectomy. sliding oblique o. an oral surgical procedure in which the mandibular ramus is cut vertically from the sigmoid notch to the angle to facilitate posterior repositioning of the mandible in correction of mandibular prognathism; it may be performed extraorally or intraorally, and is similar to vertical o.. vertical o. an oral surgical procedure similar to sliding oblique o..

osteotribe (os′te-o-trib)
An instrument for crushing off bits of necrosed or carious bone. [osteo- + G. tribo, to bruise, to grind down]

osteotrite (os′te-o-trit)
An instrument with conical or olive-shaped tip having a cutting surface, resembling a dental burr, used for the removal of carious bone. [osteo- + L. tritus, a grinding, a wearing off]

osteotrophy (os-te-ot′ro-fe)
Nutrition of osseous tissue. [osteo- + G. trophe, nourishment]

osteotympanic (os′te-o-tim-pan′ik)
SYN: otocranial. [osteo- + G. tympanon, drum]

ostia (os′te-a)
Plural of ostium. [L.]

ostial (os′te-al)
Relating to any orifice, or ostium.

ostitic (os-ti′tik)
SYN: osteitic.

ostitis (os-ti′tis)
SYN: osteitis.

ostium, pl .ostia (os′te-um, -a) [TA]
A small opening, especially one of entrance into a hollow organ or canal. SEE ALSO: orifice, opening, os, mouth (2) . [L. door, entrance, mouth] o. abdominale tubae uterinae [TA] SYN: abdominal o. of uterine tube. abdominal o. of uterine tube [TA] the fimbriated or ovarian extremity of an oviduct. SYN: o. abdominale tubae uterinae [TA] . o. anatomicum [TA] SYN: anatomical internal os of uterus. o. aortae [TA] SYN: aortic orifice. aortic o. SYN: aortic orifice. o. appendicis vermiformis [TA] SYN: orifice of vermiform appendix. o. arteriosum SYN: left atrioventricular orifice. o. atrioventriculare dextrum [TA] SYN: right atrioventricular orifice. o. atrioventriculare sinistrum [TA] SYN: left atrioventricular orifice. o. cardiacum [TA] SYN: cardial orifice. o. histologicum [TA] SYN: histological internal os of uterus. o. ileale [TA] SYN: ileal orifice. o. ileocecale SYN: ileal orifice. o. internum SYN: uterine o. of uterine tubes. o. pharyngeum tubae auditivae [TA] SYN: pharyngeal opening of pharyngotympanic (auditory) tube. o. pharyngeum tubae auditoriae pharyngeal opening of pharyngotympanic (auditory) tube. o. primum SYN: interatrial foramen primum. o. pyloricum [TA] SYN: pyloric orifice. o. secundum SYN: interatrial foramen secundum. o. sinus coronarii [TA] SYN: opening of coronary sinus. o. trunci pulmonalis [TA] SYN: opening of pulmonary trunk. o. tympanicum tubae auditivae [TA] SYN: tympanic opening of pharyngotympanic (auditory) tube. o. ureteris [TA] SYN: ureteric orifice. o. urethrae externum [TA] SYN: external urethral orifice. o. urethrae internum [TA] SYN: internal urethral orifice. o. urethrae internum evacuans [TA] SYN: voiding internal urethral orifice. o. uteri [TA] SYN: external os of uterus. o. uteri externum SYN: external os of uterus. o. uteri internum SYN: isthmus of uterus. uterine o. of uterine tubes [TA] the uterine opening of the oviduct. SYN: o. uterinum tubae uterinae [TA] , o. internum, uterine opening of uterine tubes. o. uterinum tubae uterinae [TA] SYN: uterine o. of uterine tubes. o. vaginae [TA] SYN: vaginal orifice. o. venae cavae inferioris [TA] SYN: opening of inferior vena cava. o. venae cavae superioris [TA] SYN: opening of superior vena cava. ostia venarum pulmonalium [TA] SYN: openings of pulmonary veins, under opening. o. venosum cordis SYN: right atrioventricular orifice. o. of vermiform appendix SYN: orifice of vermiform appendix.

ostomate (os′to-mat)
Term for one who has an ostomy. [L. ostium, mouth]


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