- A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint. Joints are grouped according to their motion: a ball and socket joint; a hinge joint; a condyloid joint (a joint that permits all forms of angular movement except axial rotation); a pivot joint; gliding joint; and a saddle joint. Joints can move in four and only four ways: Gliding — one bony surface glides on another without angular or rotatory movement; Angular — occurs only between long bones, increasing or decreasing the angle between the bones; Circumduction — occurs in joints composed of the head of a bone and an articular cavity, the long bone describing a series of circles, the whole forming a cone; and Rotation — a bone moves about a central axis without moving from this axis. The word "joint" comes from the Latin "junctio" meaning a joining (as in a junction).
* * *In anatomy, the place of union, usually more or less movable, between two or more bones. Joints between skeletal elements exhibit a great variety of form and function, and are classified into three general morphologic types: fibrous joints; cartilaginous joints; and synovial joints. SYN: junctura (1) [TA], arthrosis (1), articulation (1), articulus. [L. junctura; fr. jungo, pp. junctus, to join]- acromioclavicular j. [TA] a plane synovial j. between the acromial end of the clavicle and the medial margin of the acromion. SYN: articulatio acromioclavicularis [TA].- ankle j. [TA] a hinge synovial j. between the tibia and fibula above and the talus below. SYN: articulatio talocruralis [TA], ankle (1), mortise j., talocrural articulation, talocrural j..- atlanto- occipital j. [TA] a condylar synovial j. between the superior articular facets of the atlas and the condyles of the occipital bone. SYN: articulatio atlanto- occipitalis [TA], atlanto- occipital articulation.- joints of auditory ossicles [TA] the joints of the ossicular chain consisting of incudomallear j., incudostapedeal j., and the tympanostapedeal syndesmosis. SYN: articulationes ossiculorum auditus [TA], articulationes ossiculorum auditoriorum, joints of ear bones.- ball and socket j. a multiaxial synovial j. in which a more or less extensive sphere on the head of one bone fits into a rounded cavity in the other bone, as in the hip j.. SYN: articulatio spheroidea [TA], enarthrosis, spheroidal j., articulatio cotylica, cotyloid j., enarthrodial j., socket j., spheroid articulation.- biaxial j. one in which there are two principal axes of movement situated at right angles to each other; e.g., saddle joints.- bicondylar j. [TA] a synovial j. in which two more or less distinct, rounded surfaces of one bone articulate with shallow depressions on another bone. SYN: articulatio bicondylaris [TA], bicondylar articulation.- bilocular j. one in which the intraarticular disk is complete, dividing the j. into two distinct cavities.- calcaneocuboid j. [TA] a somewhat saddle-shaped synovial j. between the anterior surface of the calcaneus and the posterior surface of the cuboid. This is the lateral element of the compound transverse tarsal j.. SYN: articulatio calcaneocuboidea [TA].- carpal joints [TA] the synovial joints between the carpal bones. SYN: articulatio carpi [TA], articulationes carpi [TA], articulationes intercarpales, intercarpal joints.- carpometacarpal joints [TA] the synovial joints between the carpal and metacarpal bones; these are all plane joints except that of the thumb, which is saddle-shaped. SYN: articulationes carpometacarpales [TA].- carpometacarpal j. of thumb [TA] the saddle-shaped synovial articulation between the trapezium and the base of the first metacarpal bone. SYN: articulatio carpometacarpalis pollicis.- cartilaginous j. [TA] a j. in which the apposed bony surfaces are united by cartilage; they are divided into synchondroses and symphyses; in synchondroses, the cartilage connecting the apposed surfaces is, as a rule, ultimately converted to bone, as between epiphyses and diaphyses of long bones; exceptions are the sternal synchondroses and the cartilaginous union of the first rib and the manubrium of the sternum; in symphyses the bones are connected by a flat disk of fibrocartilage that remains unossified throughout life; e.g., the intervertebral disk and the symphysis pubis. SYN: junctura cartilaginea [TA], articulatio cartilaginis, cartilaginous articulation, synarthrodial j. (2).- Clutton joints symmetrical arthrosis, especially of the knee joints, in cases of congenital syphilis.- cochlear j. a variety of hinge j. in which the elevation and depression, respectively, on the opposing articular surfaces form part of a spiral, flexion being then accompanied by a certain amount of lateral deviation. SYN: screw j., spiral j..- complex j. [TA] a j. composed of three or more skeletal elements, or in which two anatomically separate joints function as a unit. For example, the telonavicular and calcaneocuboid joints act together as the compound transverse tarsal j.. SYN: articulatio composita [TA], articulatio complexa, composite j., compound articulation, compound j..- condylar j. [TA] a modified ball-and-socket synovial j. in which the j. surfaces are elongated or ellipsoidal; it is a biaxial j., i.e., two axes of motion at right angles to each other, the radiocarpal being an example. SYN: articulatio ellipsoidea [TA], ellipsoidal j., articulatio condylaris, condylar articulation.- costochondral joints [TA] the cartilaginous joints between the sternal end of ribs and the lateral ends of costal cartilages. SYN: articulationes costochondrales [TA], costochondral junctions.- costotransverse j. the synovial articulation between the neck and tubercle of a rib and the transverse process of a vertebra. SYN: articulatio costotransversaria.- costovertebral joints [TA] the synovial joints uniting ribs and vertebrae; they consist of the articulatio capitis costae and the articulatio costotransversaria. SYN: articulationes costovertebrales [TA].- cranial synovial joints [TA] synovial joints of the head, composed of the temporomandibular j. (TMJ) and atlanto-occipital j.. SYN: articulationes cranii [TA].- cricoarytenoid j. [TA] the synovial j. between the base of each arytenoid cartilage and the upper border of the lamina of the cricoid cartilage. SYN: articulatio cricoarytenoidea [TA], cricoarytenoid articulation.- cricothyroid j. [TA] the synovial articulation between the inferior horn of the thyroid cartilage and the side of the cricoid cartilage. SYN: articulatio cricothyroidea [TA], cricothyroid articulation.- cuboideonavicular j. a fibrous j. between adjacent parts of the cuboid and navicular bones; occasionally a synovial cavity is found here as an extension of the cuneonavicular j..- cuneocuboid j. the synovial articulation between the lateral surface of the lateral cuneiform and the anterior two-thirds of the medial surface of the cuboid.- cuneometatarsal joints SYN: tarsometatarsal joints.- cuneonavicular j. [TA] the synovial j. between the anterior surface of the navicular and the posterior surfaces of the three cuneiform bones. SYN: articulatio cuneonavicularis [TA], cuneonavicular articulation.- cylindrical j. [TA] a class of freely movable joints that rotate about a single long axis, that includes pivot and hinge joints. SYN: articulatio cylindrica [TA].- diarthrodial j. SYN: synovial j..- distal interphalangeal joints the synovial joints between the middle and distal phalanges of the fingers and of the toes. SYN: DIP joints.- distal radioulnar j. [TA] the pivot synovial j. between the head of the ulna and the ulnar notch on the radius; an articular disk passes across the distal part of the j.. SYN: articulatio radioulnaris distalis [TA], distal radioulnar articulation, inferior radioulnar j..- joints of ear bones SYN: joints of auditory ossicles.- elbow j. [TA] a compound hinge synovial j. between the humerus and the bones of the forearm; it consists of the articulatio humeroradialis and the articulatio humeroulnaris. SYN: articulatio cubiti [TA], cubital j..- ellipsoidal j. condylar j..- facet joints SYN: zygapophysial joints.- false j. SYN: pseudarthrosis.- femoropatellar j. the articulation of the facets on the articular surface of the patella with corresponding surfaces on the femoral condyles.- fibrous j. [TA] a union of two bones by fibrous tissue such that there is no j. cavity and almost no motion possible; the types of fibrous joints are sutures, syndesmoses, and gomphoses. SYN: junctura fibrosa [TA], articulatio fibrosa, immovable j., synarthrodia, synarthrodial j. (1).- flail j. a j. with loss of function caused by loss of ability to stabilize the j. in any plane within its normal range of motion.- joints of foot [TA] joints including the talocrural, intertarsal, tarsometatarsal, intermetatarsal, metatarsophalangeal and interphalangeal joints. SYN: articulationes pedis [TA], articulations of foot.- ginglymoid j. SYN: hinge j..- glenohumeral j. [TA] a ball-and-socket synovial j. between the head of the humerus and the glenoid cavity of the scapula. SYN: articulatio humeri [TA], articulatio glenohumeralis, shoulder j., glenohumeral articulation, humeral articulation.- gliding j. SYN: plane j..- gompholic j. SYN: gomphosis.- joints of hand [TA] these joints include the radiocarpal or wrist j.; intercarpal, carpometacarpal, intermetacarpal; metacarpophalangeal and interphalangeal joints. SYN: articulationes manus [TA], articulations of hand.- j. of head of rib [TA] the synovial j. between a rib and bodies of two adjacent vertebrae; the j. cavity is divided by an intra-articular ligament which attaches to the intervertebral disk; the first, tenth, eleventh, and twelfth ribs articulate with only one vertebra. SYN: articulatio capitis costae [TA], capitular j..- hinge j. [TA] a uniaxial j. in which a broad, transversely cylindrical convexity on one bone fits into a corresponding concavity on the other, allowing of motion in one plane only, as in the elbow. SYN: ginglymus [TA], ginglymoid j..- hip j. [TA] the ball-and-socket synovial j. between the head of the femur and the acetabulum. SYN: articulatio coxae [TA], coxa (2) [TA], articulatio coxofemoralis, thigh j..- humeroradial j. [TA] the portion of the elbow j. between the capitulum of the humerus and the head of the radius. SYN: articulatio humeroradialis [TA], humeroradial articulation.- humeroulnar j. [TA] the portion of the elbow j. between the trochlea of the humerus and the trochlear notch of the ulna. SYN: articulatio humeroulnaris [TA].- hysterical j. a simulation of j. disease, with symptoms of pain, possibly swelling, and impairment of motion.- immovable j. SYN: fibrous j..- incudomalleolar j. [TA] the saddle synovial j. between the incus and the malleus. SYN: articulatio incudomallearis [TA], incudomalleolar articulation.- incudostapedial j. [TA] the synovial j. between the lenticular process on the long crus of the incus and the head of the stapes. SYN: articulatio incudostapedia [TA], incudostapedial articulation.- interarticular joints SYN: zygapophysial joints.- interchondral joints [TA] the synovial joints between the contiguous surfaces of the fifth, sixth, seventh, eighth, ninth, and tenth costal cartilages, forming the costal arch. SYN: articulationes interchondrales [TA], interchondral articulations.- intercuneiform joints [TA] the articulations between contiguous surfaces of the cuneiform bones. SEE ALSO: intertarsal joints. SYN: articulationes intercuneiformes [TA].- intermetacarpal joints [TA] the synovial joints between the bases of the second, third, fourth, and fifth metacarpal bones. SYN: articulationes intermetacarpales [TA].- intermetatarsal joints [TA] the synovial joints between the bases of the five metatarsal bones. SYN: articulationes intermetatarsales [TA], intermetatarsal articulations.- interphalangeal joints of foot [TA] the hinge synovial joints between the phalanges of the toes. SYN: articulationes interphalangeae pedis [TA].- interphalangeal joints of hand [TA] the hinge synovial joints between the phalanges of the fingers. SYN: articulationes interphalangeae manus [TA], digital joints, interphalangeal articulations, phalangeal joints.- intersternebral joints SYN: synchondroses intersternebrales, under synchondrosis.- intertarsal joints the synovial joints which unite the tarsal bones. SYN: articulationes intertarseae, intertarsal articulations, tarsal joints.- jaw j. SYN: temporomandibular j..- knee j. [TA] a compound condylar synovial j. consisting of the j. between the condyles of the femur and the condyles of the tibia, articular menisci (semilunar cartilages) being interposed, and the articulation between femur and patella. SYN: articulatio genus [TA].- lateral atlantoaxial j. [TA] a condylar synovial j. between the inferior articular facets of the atlas and the superior articular facets of the axis. SYN: articulatio atlantoaxialis lateralis [TA], lateral atlantoepistrophic j..- lumbosacral j. [TA] the articulation of the fifth lumbar vertebra with the sacrum. SYN: articulatio lumbosacralis [TA], junctura lumbosacralis.- manubriosternal j. [TA] the early union, by hyaline cartilage, of the manubrium and the body of the sternum, which later becomes a symphysial type of j.. SYN: synchondrosis manubriosternalis [TA].- median atlantoaxial j. [TA] a pivot synovial j. between the dens of the axis and the ring formed by the anterior arch and the transverse ligament of the atlas. SYN: articulatio atlantoaxialis mediana [TA], Cruveilhier j., middle atlantoepistrophic j..- metacarpophalangeal joints [TA] the condylar or ellipsoid synovial joints between the heads of the metacarpals and the bases of the proximal phalanges. The palmar aspects of the metacarpal heads are partially divided, so the j. is nearly bicondylar. SYN: articulationes metacarpophalangeae [TA], metacarpophalangeal articulations, MP joints (1).- metatarsophalangeal joints [TA] the condylar or ellipsoid synovial joints between the heads of the metatarsals and the bases of the proximal phalanges of the toes. SYN: articulationes metatarsophalangeae [TA], metatarsophalangeal articulations, MP joints (2).- midcarpal j. [TA] the synovial j. between the proximal and distal rows of carpal bones. SYN: articulatio mediocarpalis [TA], middle carpal j..- movable j. SYN: synovial j..- multiaxial j. one in which movement occurs in a number of axes. See ball and socket j.. SYN: polyaxial j..- neurocentral j. SYN: neurocentral synchondrosis.- neuropathic j. destructive j. disease caused by diminished proprioceptive sensation, with gradual destruction of the j. by repeated subliminal injury, commonly associated with tabes dorsalis or diabetic neuropathy. SYN: Charcot j., neuropathic arthropathy.- joints of pectoral girdle [TA] the joints uniting the scapulae and clavicles to each other and the latter to the sternum forming the superior limb girdle; these are the acromioclavicular and the sternoclavicular joints. SYN: articulationes cinguli pectoralis, articulationes cinguli membri superioris, joints of superior limb girdle, juncturae membri superioris.- joints of pelvic girdle [TA] the joints that unite the sacrum and the two hip bones to form the pelvic girdle; these are the sacroiliac joints, the pubic symphysis, the sacrotuberal and sacrospinal ligaments, and the obturator membrane. SYN: articulationes cinguli pelvici [TA], articulationes cinguli membri inferioris, joints of inferior limb girdle.- pisiform j. [TA] the synovial j. between the pisiform and triquetrum; it is separate from the other intercarpal joints. SYN: articulatio ossis pisiformis [TA], articulation of pisiform bone, pisotriquetral j..- pisotriquetral j. SYN: pisiform j..- pivot j. [TA] a synovial j. in which a section of a cylinder of one bone fits into a corresponding cavity on the other, as in the proximal radioulnar j.. SYN: articulatio trochoidea [TA], helicoid ginglymus, lateral ginglymus, rotary j., rotatory j., trochoid articulation, trochoid j..- plane j. [TA] a synovial j. in which the opposing surfaces are nearly planes and in which there is only a slight, gliding motion, as in the intermetacarpal joints. SYN: articulatio plana [TA], arthrodia, arthrodial articulation, arthrodial j., gliding j..- polyaxial j. SYN: multiaxial j..- proximal interphalangeal joints the synovial joints between the proximal and middle phalanges of the fingers and of the toes. SYN: PIP joints.- proximal radioulnar j. [TA] the pivot synovial j. between the head of the radius and the ring formed by the radial notch of the ulna and the annular ligament. SYN: articulatio radioulnaris proximalis [TA], proximal radioulnar articulation, superior radioulnar j..- rotary j., rotatory j. SYN: pivot j..- sacrococcygeal j. [TA] the cartilaginous articulation of the coccyx with the sacrum. SYN: articulatio sacrococcygea [TA], coccygeal j., junctura sacrococcygea, sacrococcygeal junction, symphysis sacrococcygea.- sacroiliac j. [TA] the synovial j. on either side between the auricular surface of the sacrum and that of the ilium. SYN: articulatio sacroiliaca [TA], sacroiliac articulation.- saddle j. [TA] a biaxial synovial j. in which the double motion is effected by the opposition of two surfaces, each of which is concave in one direction and convex in the other; as in the carpometacarpal j. of the thumb. SYN: articulatio sellaris [TA], articulatio ovoidalis.- schindyletic j. SYN: schindylesis.- simple j. [TA] one composed of two bones only. SYN: articulatio simplex [TA].- sternoclavicular j. [TA] the synovial articulation between the medial end of the clavicle and the manubrium of the sternum and cartilage of the first rib; an articular disk subdivides the j. into two cavities. SYN: articulatio sternoclavicularis [TA].- sternocostal joints [TA] the joints between the cartilages of the first seven ribs and the sternum; synovial cavities are variable in occurrence in these joints. SYN: articulationes sternocostales [TA], sternocostal articulations.- stress-broken j. SYN: nonrigid connector.- subtalar j. [TA] a plane synovial j. between the inferior surface of the talus and the posterior articular surface of the calcaneus. The term is also used clinically to refer to the compound j. formed by the talocalcaneal and talocalcaneonavicular joints. SYN: articulatio subtalaris [TA], articulatio talocalcanea, talocalcaneal j..- synchondrodial j. [TA] SYN: synchondrosis.- synovial j. [TA] a j. in which the opposing bony surfaces are covered with a layer of hyaline cartilage or fibrocartilage; there is a j. cavity containing synovial fluid, lined with synovial membrane and reinforced by a fibrous capsule and ligaments; and there is some degree of free movement possible. SYN: junctura synovialis [TA], articulatio, diarthrosis, articulatio synovialis, diarthrodial j., movable j., perarticulation.- synovial joints of free lower limb [TA] the joints uniting the bones of the free inferior limb to one another and to the pelvic girdle; they are the hip j., knee j., tibiofibular joints, and the joints of the ankle and foot. SYN: articulationes membri inferioris liberi [TA], joints of free inferior limb, juncturae membri inferioris liberi.- synovial joints of free upper limb [TA] the joints uniting the bones of the free superior limb girdle; they are the shoulder j., elbow j., radioulnar joints, and joints of the wrist and hand. SYN: articulationes membri superioris liberi [TA], joints of free superior limb, juncturae membri superioris liberi.- synovial joints of thorax [TA] synovial joints of the thoracic skeleton, including the costovertebral, sternocostal, costochondral, and interchondral joints. SYN: articulationes thoracis [TA].- talocalcaneal j. subtalar j..- talocalcaneonavicular j. [TA] a ball-and-socket synovial j., part of which participates in the transverse tarsal j., formed by the head of the talus articulating with the navicular bone and the anterior part of the calcaneus. SYN: articulatio talocalcaneonavicularis [TA].- talonavicular j. the part of the talocalcaneonavicular j. that forms the medial element of the compound transverse tarsal j..- tarsometatarsal joints [TA] the three synovial joints between the tarsal and metatarsal bones, consisting of a medial j. between the first cuneiform and first metatarsal, an intermediate j. between the second and third cuneiforms and corresponding metatarsals, and a lateral j. between the cuboid and fourth and fifth metatarsals. SYN: articulationes tarsometatarsales [TA], cuneometatarsal joints, Lisfranc joints.- temporomandibular j. [TA] the synovial articulation between the head of the mandible and the mandibular fossa and articular tubercle of the temporal bone; a fibrocartilaginous articular disk divides the j. into two cavities. SYN: articulatio temporomandibularis [TA], articulatio mandibularis, jaw j., mandibular j., temporomandibular articulation.- thigh j. SYN: hip j..- tibiofibular j. [TA] the plane synovial j. between the lateral condyle of the tibia and the head of the fibula. SYN: articulatio tibiofibularis [TA], superior tibiofibular j., proximal tibiofibular j., superior tibial articulation, tibiofibular articulation (1).- transverse tarsal j. [TA] the synovial joints between the talus and navicular bone medially and the calcaneus and navicular bones laterally that act as a unit in allowing the front of the foot to pivot relative to the back of the foot about the longitudinal axis of the foot, contributing to the total inversion and eversion movements. SYN: articulatio tarsi transversa [TA], Chopart j., midtarsal j., transverse tarsal articulation.- uncovertebral joints small synovial joints between adjacent lateral lips of the bodies of the lower cervical vertebrae. SYN: Luschka joints.- unilocular j. one in which an intraarticular disk is incomplete or absent, the j. having but a single cavity.- wrist j. [TA] the synovial j. between the distal end of the radius and its articular disk and the proximal row of carpal bones with the exception of the pisiform bone. SYN: articulatio radiocarpalis [TA], radiocarpal articulation, radiocarpal j..- xiphisternal j. [TA] the cartilaginous union between the xiphoid process and the body of the sternum. SYN: symphysis xiphosternalis [TA], synchondrosis xiphosternalis.- zygapophysial joints [TA] the synovial joints between zygapophyses or articular processes of the vertebrae. SYN: articulationes zygapophysiales [TA], facet joints, interarticular joints, juncturae zygapophysiales.
* * *joint 'jȯint n the point of contact between elements of an animal skeleton whether movable or rigidly fixed together with the surrounding and supporting parts (as membranes, tendons, or ligaments) <the capsule of the shoulder \joint> - out of joint of a bone having the head slipped from its socket
* * *n.the point at which two or more bones are connected. The opposing surfaces of the two bones are lined with cartilaginous, fibrous, or soft (synovial) tissue. The three main classes of joint are diarthrosis (freely movable), amphiarthrosis (slightly movable), and synarthrosis (immovable).
* * *(joint) [L. junctio a joining, connection] the place of union or junction between two or more bones of the skeleton, especially one that allows motion of one or more of the bones. See also entries under articulatio and junctura.
Various kinds of joints. Fibrous: A, syndesmosis (tibiofibular); B, suture (skull). Cartilaginous: C, symphysis (vertebral bodies); D, synchondrosis (first rib and sternum). Synovial: E, condyloid (wrist); F, gliding (radioulnar); G, hinge or ginglymus (elbow); H, ball and socket (hip); I, saddle (carpometacarpal of thumb); J, pivot (atlantoaxial).
Medical dictionary. 2011.