JOINTS

JOINTSDr Khadija Iqbal

4DEFINITIONThe point where two or more bones meet is called a joint.

The other name of joints is arthroses.

5Different joints in body

6FUNCTIONSGive the skeleton mobility.

Hold the skeleton together.

7Classification of joints

On the basis of structure

On the basis of function

On the basis of movement81)Classification on the basis of structure:Solid joints: the joints without a cavity .Synovial joints: the joints with a cavity between them.

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10Types of solid joints

11Solid jointsFibrous joints: the bones are held together by fibrous connective tissue that is rich in collagen fibers. No synovial cavity

SuturesSkull only

Bony fusion

Bound by dense fibrous connective tissueTYPES:Serrate edges are saw-likeDenticulate: tooth like processes Squamous suture: bone margins overlap Plane suture: apposition of flat surfaces

12Fibrous jointscontinuedb.GomphosisTeeth to gumsPeg and socket joint

c.Syndesmosesbones connected by ligaments

13Types of solid joints....continued2)Cartilaginous joints: The bones are held together by cartilage.

Synchondroses/primary cartilaginous joints On completion of growth hyaline cartilage is replaced by bonee.gepiphyseal cartilage of long bonesbetween vertebrosternal ribs and sternum

14Types of cartilagenous jointscontinuedb. Symphyses/ secondary cartilaginous jointsbones separated by fibro cartilageMostly permanente.g.pubic symphysisIntervertebral discsSome joints e.g. between sacrum and coccyx undergo partial or complete synostosis

15II. Synovial jointsmore movementwithin articular capsules lined with synovial membranewhere synovial fluid is found

16Accessory structures of synovial jointcontinuedArticular/Hyaline CartilageSmooth cartilage at the end of bones at jointTwo-Layered Joint CapsuleOuter Layer Tough fibrous capsuleInner Layer Synovial Membrane Synovial FluidSlippery fluid in joint capsule LigamentA band of strong fibrous tissue

17Accessory structures of synovial jointcontinuedArticular/Hyaline CartilagePrevent friction between articulating bonesTwo-Layered Joint CapsuleOuter Layer Strengthen jointInner Layer To secrete synovial fluid Synovial FluidReduce friction between articular cartilagesNourish articular cartilageLigamentTo connect one bone to another

18Accessory structures of synovial jointcontinued Tendons Strong connective tissue that attaches muscle to bone.

Connect muscle to muscle.

BursaFluid filled sacs

Cushion the joint and act as shock absorbersMeniscus White fibrocartilage

Improves the fit between bone ends Increases joint stabilityReduces wear and tear at joint

19SYNOVIAL JOINT

20Types of synovial joints

21Types of synovial jointscontinuedPlane joints :the articulating surfaces are flat or slightly curved. e.g are intercarpal joints, intertarsal joints, sternoclavicular joints, acromioclavicular joints, sternocostal joints, vertebrocostal joints.etc.

22Examples of plane joint

23Types of synovial jointscontinuedHinge Joints-the convex surface of one fits into the concave surface of another. e.g. elbow joint, ankle joint, interphalangeal joints,etc.

24Types of synovial jointscontinuedPivot Joints-here the rounded or pointed surface of one bone articulates with a ring formed partly by another bone and partly by a ligament. e.g atlanto-axial joint, radioulnar joint etc.

25Types of synovial jointscontinuedCondyloid Joints-also called ellipsoidal joint. The convex oval-shaped projection of one fits into the oval-shaped depression of another e.g metacarpophalangeal joints.

26Types of synovial jointscontinuedSaddle Joints-here the articular surface of one bone is saddle-shaped and the articular surface of the other fits into the saddle.e.g. Carpometacarpal joint.

27Types of synovial jointscontinuedBall-and-Socket Joints- this consists of the ball-like surface of one bone fitting into a cuplike depression of another bonee.g Shoulder and hip joints.

282)Classification on the basis of functionFunctionally, joints are classified as one of the following:Synarthrosis: an immovable joint.

Amphiarthrosis: a slightly movable joint. Most amphiarthrosis joints are cartilaginous.

Diarthrosis: a freely movable joint. All diarthroses are synovial joints.

293)CLASSIFICATION ON THE BASIS OF MOVEMENT Uniaxial joints e.g. the elbow joint

Biaxial joints e.g. the wrist joint

30CLASSIFICATION ON THE BASIS OF MOVEMENTcontinuedMultiaxial joints: e.g. shoulder joint

31Factors affecting at Synovial JointsStructure or shape of the articulating bonesStrength and tension of ligaments.Arrangement and tension of musclesApposition of soft partsHormonesuse

3132Vasculature of jointsArticular arteries from vessels around jointsOften these arteries form anastamoses around jointsArticular veins accompany arteriesArticular veins like articular arteries, are located inside a joint capsule, mostly in the synovial membranes

33InnervationRich nerve supplyMost articular nerves are branches of cutaneous nerves supplying the muscles that cross and move the joint( obey Hiltons law)In distal parts of limbs( hands and feet) articular nerves are branches of cutaneous nerves supplying the overlying skin

34Innervation continuedJoints transmit a sensation called proprioceptionSynovial membrane is relatively insensitivePain fibers are numerous in fibrous layer and associated ligaments causing pain when joints are injuredSensory nerve endings respond to twisting and stretching that occur during sport activities

35Joints of new bornThe bones of the calvarium (skullcap) of a new born infant do not make full contact with each otherAt these sites, the sutures form wide areas of fibrous tissue called fontanelles

36DEGENERATIVE JOINT DISEASESRisk factors include age ,heredity, injury and obesityParticularly those of hip, knee, vertebral column and handsSome destruction is inevitable during such activities as jogging, which wears away the articular cartilages and sometimes erodes the underlying articular surfacesTrauma to a joint may be followed by arthritis ,inflammation of joint and septicemia

37Degenerative joint diseases..continuedMost common is osteoarthritis, which is often accompanied by stiffness, discomfort and pain.

38Degenerative joint diseases..continuedRheumatoid arthritisChronic inflammatory disorderMarked by flare-upsAutoimmune disease.

39Degenerative joint diseases..continued

40Examination of jointClinical examinationImaging( MRI/CT)ArthroscopyA cannula and arthroscope is inserted in joint cavityFor abnormalities such as torn articular discs

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