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Joint

A joint is the location at which two or more [|bones] make contact. Joints have various functions such as binding parts of skeletal system, making bone growth possible, enabling body to move in response to skeletal muscle contraction, and making shape change of the skeleton during childbirth possible.  Joints are classified into 3 categories depending on how much they can move and how they are structured.

Fibrous joints are __//immovable//__; Cartilaginous joints are //__slightly movable__//; Synovial joints are //__freely moving__//. Fibrous joints are joined by //__fibrous connective tissue__//; Cartilaginous joints are joined by //__cartilage__//; Synovial joints are //__not directly joined__//.

===(1) Fibrous joints (also known as Synarthrotic joints - "Syn-" means together, and "arthr-" stands for joint.) === Fibrous joints are considered immovable . They are comprised of dense connective tissues that connect bones and are located Between bones in close contact There are three different types of fibrous joints. __Syndesmosis:__ __Suture:__  __Gomphosis:__
 * These types are made of a sheet or bundle of fibrous tissue connecting bone.
 * These joints are slightly movable and are united by an [|interosseous ligament].
 * An example of this would be in between the tibia and fibula
 * Sutures lie between flat bones
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">A way to distinguish if a joint is a suture or not is by looking for teeth-like projections
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">They are comprised of thin layer of densely packed connective tissue
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">An example of suture would be Skull
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">These are Cone-shaped bony processes in a socket
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">The motion of a gomphosis is very minimal, though considerable movement can be achieved over time
 * <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">An example is teeth in the jawbone.

===<span style="color: black; font-family: 'Times New Roman','serif'; margin: auto 0cm auto 19.5pt; tabstops: list 36.0pt; text-indent: -18pt;">(2) Cartilaginous joints (Amphiarthrotic joints-"Amphi-" means both or dual; The term amphiarthrotic means then, that these joints offer both a bit of mobility and a bit of sturdiness.) === <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; margin: 0cm 0cm 0pt; tab-stops: list 36.0pt; tabstops: list 36.0pt;">Cartilaginous joints are slightly movable <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; margin: 0cm 0cm 0pt; tab-stops: list 36.0pt; tabstops: list 36.0pt;">. For these joints, Hyaline cartilage or fibro cartilage connects bone. <span style="display: block; margin-bottom: 0pt; margin-left: 0cm; margin-right: 0cm; margin-top: 0cm; text-align: left;"><span style="color: black; display: block; font-family: 'Times New Roman','serif'; font-size: 12pt; text-align: left;">There are two types of cartilaginous joints. __Synchondrosis joints;__
 * Bands of hyaline cartilage unite bones
 * These can be found between the manubrium and the first rib (costal cartilages)

__Symphysis:__
 * Symphysis is joints between bodies of adjacent vertebrae.
 * Unlike [|synchondroses], symphyses are permanent
 * An example of symphysis pubic symphysis

===<span style="font-size: 1.1em; margin: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 5px;">**<span style="color: black; font-family: 'Times New Roman',serif; margin: auto 0cm auto 19.5pt; text-indent: -18pt;">(3) Synovial joints (also known as diarthoses) ** === ====<span style="font-family: Arial,Helvetica,sans-serif;">Synovial joints are <span style="color: #ff0000; font-family: Arial,Helvetica,sans-serif;">freely moving <span style="font-family: Arial,Helvetica,sans-serif;">. <span style="color: black; font-family: 'Times New Roman',serif; font-size: 12pt; margin: 0cm 0cm 0pt; padding: 0px;">Cavities between bones in synovial joints are filled with synovial fluid which not only lubricates but also protects the bones. ====

There are 3 types of synovial joints.
__Uni-Axial (one which permits movement in one axis only):__ __Bi-Axial (one which permits movement in two axis):__
 * Hinge joints; the articular surfaces are molded to each other in such a manner as to permit motion in only one plane-- backward and forward. An example of this would be the elbow.[[image:joint1A.gif]]
 * Pivot joints; one bone pivots within a bony or osseoligamentous ring. This kind can be found between the atlas and dens of the axis.
 * Saddle joint; the opposing surfaces are paired concave-convex. The movements are the same as in the condyloid joint but no axial rotation. An example of this is between the carpal and first metacarpal of the thumb.[[image:SADDLE.JPG]]
 * Ellipsoidal joint; an ovoid head of one bone moves in an elliptical cavity of another, permitting all movements except axial rotation. These can be found between metacarpals and phalanges or between the radius and carpals.

__Multi-Axial (one which permits movement in multiple axis):__
 * Ball and socket joint; spherical surfaces furnished by one bone working within a cup furnished by another which allows the first of the two bones to have free movement. Examples of this are the hip and shoulder joints.[[image:images-1.jpeg]]
 * Gliding joints; flat articular surfaces that slide against each other. The tarsal joint of the foot and the intercarpal joints of the wrist are examples of these.

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