the site of the junction or union of two or more bones of the body; its primary function is to provide motion and flexibility to the frame of the body. Some are immovable, such as the sutures
where segments of bone are fused together in the skull. Others, such as those between the vertebrae, are gliding joints
and have limited motion. However, most joints allow considerable motion. The most common type are the synovial joints
, which have a complex internal structure, composed not only of ends of bones but also of ligaments
, the articular capsule
, the synovial membrane
, and sometimes bursae
acromioclavicular joint the point at which the clavicle joins with the acromion.
the joint between the foot and the leg; see ankle
a synovial joint
in which the rounded or spheroidal surface of one bone (the “ball”) moves within a cup-shaped depression (the “socket”) on another bone, allowing greater freedom of movement than any other type of joint. See illustration. Called also polyaxial
or spheroidal joint
) a type of synovial joint
in which more than two bones are involved.
condylar joint (condyloid joint) one in which an ovoid head of one bone moves in an elliptical cavity of another, permitting all movements except axial rotation; this type is found at the wrist, connecting the radius and carpal bones, and at the base of the index finger. See illustration.
facet j's the articulations of the vertebral column.
flail joint an unusually mobile joint, such as results when joint resection is done to relieve pain.
a synovial joint
in which the opposed surfaces are flat or only slightly curved, so that the bones slide against each other in a simple and limited way. The intervertebral joints are this type, and many of the small bones of the wrist and ankle also meet in gliding joints. Called also arthrodial joint
and plane joint
a synovial joint
that allows movement in only one plane, forward and backward. Examples are the elbow and the interphalangeal joints of the fingers. The jaw is primarily a hinge joint but it can also move somewhat from side to side. The knee and ankle joints are hinge joints that also allow some rotary movement. See illustration. Called also ginglymus
a synovial joint
in which one bone pivots within a bony or an osseoligamentous ring, allowing only rotary movement; an example is the joint between the first and second cervical vertebrae (the atlas and axis). See illustration. Called also rotary
or trochoid joint
the joint between the sacrum and ilium in the lower back; see also sacroiliac joint
a synovial joint
whose movement resembles that of a rider on horseback, who can shift in several directions at will; there is a saddle joint at the base of the thumb, so that the thumb is more flexible and complex than the other fingers but is also more difficult to treat if injured.
a type of synovial joint
in which only two bones are involved.
a specialized joint that permits more or less free movement, the union of the bony elements being surrounded by an articular capsule
enclosing a cavity lined by synovial membrane
. Called also articulation
. A capillary network in the synovial membrane provides nutrients and synovial fluid to nourish and lubricate the joint space. Strong fibrous bands or cords (ligaments)
give strength and security to synovial joints. The majority of the body's joints are of this type. They are divided into five types according to structure and motion: ball and socket
, and pivot
joint (joynt) [Fr. jointe, fr L. junctio, a joining]
TYPES OF JOINTS
TYPES OF JOINTS
TYPES OF JOINTS
TYPES OF JOINTS
TYPES OF JOINTS
TYPES OF JOINTS
The place where two or more bones meet. Some joints are fixed or immobile attachments of bones; other joints allow the bones to move along each other. A joint usually has a thin, smooth articular cartilage on each bony surface and is enclosed by a joint capsule of fibrous connective tissue. A joint is classified as immovable (synarthrodial), slightly movable (amphiarthrodial), or freely movable (diarthrodial). A synarthrodial joint is one in which the two bones are separated only by an intervening membrane, such as the cranial sutures. An amphiarthrodial joint is one having a fibrocartilaginous disk between the bony surfaces (symphysis), such as the symphysis pubis; or one with a ligament uniting the two bones (syndesmosis), such as the tibiofibular articulation. A diarthrodial joint is one in which the adjoining bone ends are covered with a thin cartilaginous sheet and joined by a joint capsule lined by a synovial membrane, which secretes synovial fluid. Synonym: arthrosis
(1) See: illustration
Joints are also grouped according to their motion: ball and socket (enarthrodial); hinge (ginglymoid); condyloid; pivot (trochoid); gliding (arthrodial); and saddle joint.
Joints can move in four ways: gliding, in which one bony surface glides on another without angular or rotatory movement; angulation, occurring only between long bones, increasing or decreasing the angle between the bones; circumduction, occurring 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, in which a bone moves about a central axis without moving from this axis. Angular movement, if it occurs forward or backward, is called flexion or extension, respectively; away from the body, abduction; and toward the median plane of the body, adduction.
Because of their location and constant use, joints are prone to stress, injury, and inflammation. The main diseases affecting the joints are rheumatic fever, rheumatoid arthritis, osteoarthritis, and gout. Injuries comprise contusions, sprains, dislocations, and penetrating wounds.
acromioclavicular joint Abbreviation: AC joint
A gliding or plane joint between the acromion and the acromial end of the clavicle.
A joint that is both ginglymoid and arthrodial.
Diarthrosis permitting a gliding motion. Synonym: gliding joint
A joint in which the round end of one bone fits into the cavity of another bone. Synonym: enarthrodial joint; multiaxial joint; polyaxial joint
A joint with two chief movement axes at right angles to each other.
A joint separated into two sections by interarticular cartilage.
Hemorrhage into joint space in hemophiliacs. Synonym: hemophilic joint
Budin joint See: Budin joint
A joint with cartilage between the bones.
Charcot joint See: Charcot, Jean M.
Chopart joint See: Chopart, François
Clutton joint See: Clutton joint
A hinge joint permitting lateral motion. Synonym: spiral joint
A joint made up of several bones.
condylar jointEllipsoid joint.
A joint permitting all forms of angular movement except axial rotation.
The sound produced by forcible movement of a joint by contracting the muscles that contract or extend a joint, esp. the metacarpophalangeal joints. The cause is not known. See: crepitation
Either of the encapsulated, double synovial joints between the condylar processes of the mandible and the temporal bones of the cranium. The double synovial joints are separated by an articular disk and function as an upper gliding joint and a lower modified hinge or ginglymoid joint. Synonym: temporomandibular joint See:
A joint characterized by the presence of a cavity within the capsule separating the bones, permitting considerable freedom of movement.
Arthritis of the chronic villous type.
The hinge joint between the humerus and the ulna.
A joint with two axes of motion through the same bone. Synonym: condylar joint
enarthrodial jointBall-and-socket joint.
Any of the zygapophyseal joints of the vertebral column between the articulating facets of each pair of vertebrae.
A false joint formation after a fracture.
Any of the joints connected by fibrous tissue.
A joint that is extremely relaxed, the distal portion of the limb being almost beyond the control of the will.
A synovial joint having only forward and backward motion, as a hinge. Synonym: ginglymus
See: hinge joint
gliding jointArthrodial joint.
hemophilic jointBleeders' joint.
a synovial joint in which two bones flex and extend in only one plane, usually because side (collateral) ligaments limit the direction of motion, e.g., elbow joint.
A synovial ball-and-socket joint in which the head of the femur fits into the acetabulum of the hip bone. More than seven separate ligaments hold the joint together and restrict its movements.
Any of the articulations formed by the carpal bones in relation to one another.
A recurrent joint inflammation of unknown cause.
The joint formed by the femur, patella, and tibia.
A joint separating the navicular, lunate, and triangular bones from the distal row of carpal bones.
A slightly movable or freely movable joint, amphiarthrodial and diarthrodial, respectively.
multiaxial jointBall-and-socket joint.
A joint that permits rotation of a bone, the joint being formed by a pivot-like process that turns within a ring, or by a ringlike structure that turns on a pivot. Synonym: rotary joint; trochoid joint
A synovial joint between bone surfaces, in which only gliding movements are possible.
polyaxial jointBall-and-socket joint.
A technique for minimizing stress on joints, including proper body mechanics and the avoidance of continuous weight-bearing or deforming postures.
receptive jointSaddle joint.
rotary jointPivot joint.
The articulation between the sacrum and the ilium of the hip bone. Joint movement is limited because of interlocking of the articular surfaces.
A joint in which the opposing surfaces are reciprocally concavoconvex. Synonym: receptive joint
The ball-and-socket joint between the head of the humerus and the glenoid cavity of the scapula.
A joint composed of two bones.
A multiaxial joint with spheroid surfaces.
spiral jointCochlear joint.
The joint space between the sternum and the medial extremity of the clavicle.
A joint with reduced mobility.
Any of the three articular surfaces on the inferior surface of the talus.
An articulation between two cranial or facial bones.
A joint in which the articulating surfaces are separated by synovial fluid. See: joint for illus
A joint composed of three arthrodial joints, the bones of which articulate with the bases of the metatarsal bones.
temporomandibular jointCraniomandibular joint.
trochoid jointPivot joint.
The functional articulation of the distal ulna, articular disk, and triquetrum. The disk may subluxate following injury or with arthritis and block supination of the forearm.
A joint moving on a single axis.
A joint with a single cavity.
the site of the junction or union of two or more bones of the body. See also arthritis
. The primary functions of joints are to provide motion and flexibility to the skeletal frame, or to allow growth.
Some joints are immovable, such as certain fixed joints where segments of bone are fused together in the skull. Other joints, such as those between the vertebrae, have extremely limited motion. However, most joints allow considerable motion.
Many joints have a complex internal structure. They are composed not merely of ends of bones but also of ligaments, which are tough whitish fibers binding the bones together; cartilage, which is connective tissue, covering and cushioning the bone ends; the articular capsule, a fibrous tissue that encloses the ends of the bones; and the synovial membrane, which lines the capsule and secretes a lubricating fluid (synovia).
Joints are classified by variations in structure that make different kinds of movement possible. The movable joints are usually subdivided into hinge, pivot, gliding, ball-and-socket, condyloid and saddle joints.
For a complete named list of joints in the body see Table 11.
a synovial joint in which the rounded or spheroidal surface of one bone ('ball') moves within a cup-shaped depression ('socket') on another bone, allowing greater freedom of movement than any other type of joint. Called also spheroidal joint.
permits movement around two axes.
one in which the bones are united by cartilage, providing either slight flexible movement or allowing growth; it includes symphyses and synchondroses.
one in which an ovoid head of one bone moves in an elliptical cavity of another, permitting all movements except axial rotation. Called also condylar joint.
degenerative joint disease
a disease of the joints of all species and all ages but reaching a particularly high prevalence in pen-fed young bulls in which it is characterized by the sudden onset of lameness in a hindlimb, with pain and crepitus in the hip joint and rapid wasting of the muscles of the croup and thigh. There is a family predisposition to this degenerative arthropathy; it is exacerbated by a diet high in phosphorus and low in calcium and dense in energy so that the bull has a high body weight and is growing fast. The onset is acute and often precipitated by fighting or mating. The disease may not develop until 3 or 4 years of age in bulls that are reared at pasture. Called also coxofemoral arthropathy. See also hip
circumference of the joint is an ellipse with the articular surfaces longer in one direction than the other.
includes arthritis, arthropathy, rickets.
the synovial joints of the vertebral column between the neural arches.
a combination of fibrous and cartilaginous joints. Called also amphiarthrosis. Movement limited and variable.
one in which the bones are connected by fibrous tissue; it includes suture, syndesmosis and gomphosis.
includes ankylosis, tendon contracture, arthrogryposis.
an unusually mobile joint.
see hinge joint (below).
a synovial joint in which the opposed surfaces are flat or only slightly curved, so that the bones slide against each other in a simple and limited way. The synovial intervertebral joints are gliding joints, and many of the small bones of the carpus and tarsus meet in gliding joints. Called also arthrodial joint and plane joint.
a synovial joint that allows movement in only one plane, through the presence of a pair of collateral ligaments that run on either side of the joint. Examples are the elbow and the interphalangeal joints of the digits. The jaw is primarily a hinge joint, but it can also move somewhat from side to side. The carpal and tarsal joints are hinge joints that also allow some rotary movement. Called also ginglymus.
the joint between the head of the femur and the acetabulum of the hip bone; loosely called hip.
hyaline cartilage joint
see cartilaginous joint (above).
joint can be extended beyond the normal position.
usually a congenital defect with all joints affected. Degree varies from extreme, in which limbs can be tied in knots and animal unable to stand, to mild, in which the patient is able to walk but the gait is abnormal. There may be additional defects such as pink teeth lacking enamel and dermatosparaxis (hyperelastosis cutis). See also hereditary
1. the joint between the femur and tibia, fibula and patella.
2. in large ungulates the compound joint between the radius, ulna, carpus and metacarpus.
fragments of cartilage or bone that lie free in the joint space. See also joint mouse
inflexible joint composed of bone; called also synostosis.
a joint in which one bone pivots within a bony or an osseoligamentous ring, allowing only rotary movement; an example is the joint between the first and second cervical vertebrae (the atlas and axis).
see gliding joint (above).
sensory nerve endings capable of detecting the position or angle of the joint.
the articulating surfaces are reciprocally saddle-shaped and permit movement of all kinds, though not rotation, e.g. interphalangeal joints in the dog.
see ball-and-socket joint (above).
a fixed joint.
a specialized form of articulation permitting more or less free movement, the union of the bony elements being surrounded by an articular capsule enclosing a cavity lined by synovial membrane. Called also diarthrosis and diarthrodial joint.
see pivot joint (above).
permits movement in one direction only.