JOINTS AND ITS CLASSIFICATION
Presented by Ispita bhattacharjee MPT 2nd year
INTRODUTION
Definition
Basic principle
Human joint design Classification
Conclusion Reference
Definition
joint is where two bones come together. The joints hold the bones together and allow for movement of the skeleton. A All of the bones, except the hyoid bone in the neck, form a joint. Joints are often categorized by the amount a mount of motion they allow. Some of the joints are fixed, like those in the skull, allow for no movement, Other joints, like those between the vertebrae of the spine allow some movement and most of the joint are a re free moving synovial joint. A A
Basic
principle
joint (articulation) is used to connect one component of a structure structure with one or more more other components. The design of a joint is determined by its function and the nature of its components. The function of the joint is stability, and therefore the design must be united to form a stable union. Joints that serve a single function are less complex than joints that serve multiple function.
A
Human
joint design
The joint design in the human body vary from simple and complex. Most joints in the human body have to serve a dual mobility/stability function and must provide dynamic stability. Bracing of human joint is accomplished through the use of joint capsule, ligament and tendons.
JOINT STRUCTURE
CLASSIFICATION OF JOINTS Joints of the human body are divided into two broad categories based on the type of material and methods used to unite the bony components Structural classification: It determined by how the bones connect to each other. There are three structural classification. Fibrous joint 1. Cartilaginous joint 2. Synovial joint 3. Functional classification: It can also be classified functionally, by the degree of mobility they allow. 1. Synarthrosis 2. A Amphiarthrosis 3. Diarthrosis
Structural joint classification
1.
2.
3.
Fibrous joint : In fibrous joint, the fibrous tissue directly unites bone to bone. Three different type of fibrous joints are found in the human body Suture joint : An immovable joint is formed by a thin layer of fibrous tissue. The ends of bony components are shaped so that the edges interlock or overlap one another. Gom phosis joints :An articulation by the insertion of a conical process into a socket, such as the insertion of a root of a tooth into an alveolus of the mandible or the maxilla Syndemosis :An immovable immovablee joint immovabl joint for formed med by by connective connective tissue tissue between two bones. For example, the articulation between the fibula the fibu fi bula la and tibia at the the ankle is formed by strong ligaments. ligaments.
Cartilaginous joint : The material used to connect the bony component in cartilaginous joint are either a fibro cartilage or hyaline cartilage. There are two type of cartilaginous joint.
Sym physis joint: the two bony components are directly joined by fibro cartilage in the form of disks or plates. e.g.: symphysis pubis
Synchondrosis: The material used for connecting the two components is hyaline growth cartilage. e.g : 1st sterocostal joint
Synovial joint: the ends of the body components are free to move in relation to one another because no cartilaginous tissue tissue directly connect the adjacent bony surfaces. The bony components are indirectly connected to one another by means of a joint capsule that enclose the joint. All synovial joint are constructed in same manner : A A joint capsule formed by fibrous tissue. A A joint cavity is enclosed by the joint capsule. A A synovial membrane that lines the inner surface of the capsule. Synovial fluid that forms the film over the joint surfaces. Hyaline cartilage that cover the joint surface.
Type of s ynovial joints:
joints: In which a spherical knob or part of one bone fits into a cavity or socket socke t of another, so that some degree of rotary motion is possible in every direction. Pivot joints : In which a bone rotates around another, a joint permitting only rotating movement. Condyloid or ellipsoidal joints : In which an ovoid head of one bone moves in an elliptical cavity of another, permitting all movements except axial rotation. Saddle joints : joint of the lower thump and metacarpals, me tacarpals, in which the double motion is effected by the opposition of two surfaces, each of which is concave in one direction and convex in other. Gliding joint :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. Ball and socket
Ball and socket joint
Pivot
joint
Condyloid joint
Saddle joint
Gliding joint
Functional joint classification It can also be classified functionally, by the degree of mobility they allow. They classified in three type.
Synarthrosis : which permits little or no mobility. most of the are fibrous joint. e.g. skull A Amphiarthrosis : permits a slight movement. Most of joint are cartilaginous. e.g. vertebrae moveme nt. Synovial joint. Diarthrosis : permits a variety of movement. e.g. hip, knee, shoulder etc
Biomechanical
classification
Joint can be classified based on their anatomy or biomechanical properties: these are Simple joint : Two articulation surfaces
Compound joint : Three or more articulation surfaces.
Complex joint : Two or more articulation surfaces.
Biomechanics
of Joint
kinematics
Open kinematics
Closed kinematics
chain : It is a type of motion which occurs at one of the joints but associated with series of a joint. inematics K ine
Open kinematics chain : when the ends of the limb or part of the body are free to move without causing motion at another joint.
e.g. waving the hand. Closed kinematics chain : when the one joint is performed associated with other joint. e.g. sit up
Arthrokinematics Its refers to movements of joint, when motion at the joint occurs as the result of movement of one joint surfaces in relation to another. Type of a arthrokinematics : Rolling : It refers to the rolling of one joint surfaces on another. e.g. femoral condyles roll on the fixed tibial surfaces. Sliding : which is a pure translatory movement, refers to gliding of one compartment over another. e.g. In hand , the PIP slides over the fixed end of the MCP Spinning : a rotation of the movable component, as when a top spins. e.g. supination and pronation of the forearm
The type of motion that occurs at particular joint depends on the shape of the articulating surfaces. It could be either ovoid or a sellar joint. Ovoid joint : In ovoid joint, one surfaces is concave or other surfaces is convex. Sellar joint : In sellar joint, each joint surfaces is both convex and concave.
Osteokinematics Osteokinematics refers to the movement of the bone rather than the movement of articular surfaces. The normal range of motion (ROM) of a joint is sometimes called automatic or physiologic ROM, because the normal range refers to the amount of motion available within the anatomic limits of the joint structure. The anatomic range is depend on the shape of the joint surfaces, joint capsule , ligament ,muscle bulk, and surrounding musculotendinous musculotendinous and bony structure. In some joint there are no bony restriction to motion in addition to soft tissue limitations. e.g. knee joint
Pathomechanics
W W hen hen
of the joint
the motion at a joint either e ither exceeds or fail to reach the normal anatomic limits of motion. W W hen hen a range of motion exceeds the normal limits the joint is hypermobile. W W hen hen the range of motion is less than what would normally permit by the structure, the joint is hypomobile. Hypermobilty may be caused by failure to limit motion motion by either the bony or soft tissues and results in instability. Hypomobility may be caused by bony or cartilaginous blocks to motion or by the inability of the capsule or the ligament to elongate sufficiently to allow a normal ROM. either hypermobilty or hypomobility of ajoint may have undesirable effects, not only the joint but also on adjacent joint structure.
Conclusion
It explain about the classification, function, design and mobility of a joint and how synovial fluid, synovial membrane, tendons, ligaments and bone works together to provide mobility and dynamic stability to the joint structures. It explain about the motion of joints take place in various kinematics. It also helps to know the affect of injury, disease and ageing of bone.
Reference www.wikipedia.com www.google.com
Joint structure and function by cynthia. C. norkin Human anatomy by B.D.Chaurasia
