Introduction of The Arthrology School of Basic Medical Science of Jiujiang University

1. David Fu Introduction of The ArthrologySchool of Basic Medical Science of Jiujiang University

2. Arthrology In order to serve the purposes of protection and movement, the bones must be joined together one another by connective tissue at different parts of their surfaces, and such connections are termed Joints or Articulations. They can be classified according to how the adjacent bones are joined into fibrous joints, cartilaginous joints and synostosis. They can also be divided on the basis of their relative freedom of movement into synarthrosis and diarthrosis.

3. Synarthrosis The synarthrosis occurs between the bones that in almost direct contact, fastened together by intervening connective tissue or hyaline cartilage, and in which there is no appreciable motion. It includes the fibrous joints, cartilaginous joints, synostosis.

4. Fibrous Joints 1. Lack a synovial cavity 2. Bones held closely together by fibrous connective tissue 3. Little or no movement 4. 3 structural types Sutures Syndesmosis Gomphosis

5. Sutures 1.Thin layer of dense fibrous connective tissue unites bones of the skull 2.Immovable (synarthrosis) 3.If fuse completely in adults is synostosis

6. Syndesmosis • 1.Fibrous joint • bones united by ligament • 2.Slightly movable (amphiarthrosis) • 3.Anterior tibiofibular joint and Interosseous membrane

7. Gomphosis 1.Ligament holds cone-shaped peg in bony socket 2.Immovable (amphiarthrosis) 3.Teeth in alveolar processes

8. Cartilaginous Joints • 1. Lacks a synovial cavity • 2. Allows little or no movement • 3. Bones tightly connected by fibrocartilage or hyaline cartilage • 4. 2 types • synchondrosis • symphysis

9. Synchondrosis 1. Connecting material is hyaline cartilage 2. Immovable 3. between ribs and sternum 4. It is a temporary form of joint

10. Symphysis • Fibrocartilage is connecting material • 2. Slightly movable • 3. Intervertebral discs and pubic symphysis

11. Synostosis The bones are united by the ossification of the fibrous joint or synchondrosis between them, e. g. , the synosteosis between the ilium, ischium and pubis of the hip bones.

12. Diarthrosis ----Synovial joints The bones of a diarthrosis are separated by a synovial cavity, and so is also called the synovial joint. This class includes the greater number of the joints in the body. Articular surface, articular capsule and articular cavity are the characteristics of synovial joint. In such a joint, the contiguous bony surface are covered with articular cartilage, and connect by a surrounding, tuber like capsule of dense fibrous tissue. The joint may be divided, completely, by an articular disc or meniscus, the periphery of which is continuous with the fibrous capsule. More synovial joints within the skeletal system are freely movable normally; however, the actual range of movement depending on the requirements for function and stability.

13. Essential structures of synovial joints • Articular surface: covered by articular cartilage articular head articular fossa • Articular capsule • Fibrous membrane • Synovial membrane • Articular cavity: containing a trace of synovial fluid; subatmospheric pressure in it

14. Example of Synovial Joint • Joint space is synovial joint cavity • Articular cartilage covering ends of bones • Articular capsule

15. Synovial membrane • Synovial membrane • inner lining of capsule • secretes synovial fluid containing hyaluronic acid (slippery) • brings nutrients to articular cartilage

16. Accessory structures of synovial joints • Accessory ligaments • extracapsular ligaments • outside joint capsule • intracapsular ligaments • within capsule • Articular discs or menisci • attached around edges to capsule • allow 2 bones of different shape to fit tightly • increase stability of knee - torn cartilage • Articular labrum • Synovial fold synovial fat cushion • Synovial bursa = saclike structures between structures • skin/bone or tendon/bone or ligament/bone

17. Bursae and Tendon Sheaths • Bursae • fluid-filled saclike extensions of the joint capsule • reduce friction between moving structures • skin rubs over bone • tendon rubs over bone • Tendon sheaths • tubelike bursae that wrap around tendons at wrist and ankle where many tendons come together in a confined space • Bursitis • chronic inflammation of a bursa

18. Nerve and Blood Supply • Nerves to joints are branches of nerves to nearby muscles • Joint capsule and ligaments contain pain fibers and sensory receptors • Blood supply to the structures of a joint are branches from nearby structures • supply nutrients to all joint tissues except the articular cartilage which is supplied from the synovial fluid

19. Types of Joint Movements • Gliding (or slipping) movement • Flexion and extension • Adduction and abduction • Rotation • Pronation and supination • Inversion and eversion • Circumduction

20. Uniaxial joints: hinge joints trochoid (pivot) joints Biaxial joints: ellipsoid joints saddle joints Multiaxial joints: ball-and-socket joint plane joints Types of synovial joints

21. Uniaxial joints --Hinge Joint • Convex surface of one bones fits into concave surface of 2nd bone • Uniaxial like a door hinge • Examples • Knee, elbow, ankle, interphalangeal joints • Movements produced • flexion = decreasing the joint angle • extension = increasing the angle • hyperextension = opening the joint beyond the anatomical position

22. Flexion, Extension & Hyperextension

23. Uniaxial joints --Pivot Joint • Rounded surface of bone articulates with ring formed by 2nd bone & ligament • Monoaxial since it allows only rotation around longitudinal axis • Examples • Proximal radioulnar joint • supination • pronation • Atlanto-axial joint • turning head side to side “no”

24. Biaxial joints –Condyloid or Ellipsoidal Joint • Oval-shaped projection fits into oval depression • Biaxial = flex/extend or abduct/adduct is possible • Examples • wrist and metacarpophalangeal joints for digits 2 to 5

25. Adduction and Abduction Condyloid joints Ball and Socket joints

26. Biaxial joints – Saddle Joint • One bone saddled-shaped; other bone fits as a person would sitting in that saddle • Biaxial • Circumduction allows tip of thumb travel in circle • Opposition allows tip of thumb to touch tip of other fingers • Example • trapezium of carpus and metacarpal of the thumb

27. Multiaxial joints –Ball and Socket Joint • Ball fitting into a cuplike depression • Multiaxial • flexion/extension • abduction/adduction • rotation • circumduction • Examples • shoulder joint • hip joint

28. Multiaxial joints – Plane Joint • Bone surfaces are flat or slightly curved • Side to side movement only • Rotation prevented by ligaments • Examples • intercarpal or intertarsal joints • sternoclavicular joint • vertebrocostal joints

29. Summary of Movements at Synovial Joints • Gliding • no change in angle of joint • Angular movements • increase or decrease in angle between articulating bones • flexion, extension, hyperextension • abduction, adduction • circumduction is a combination of above movements • Rotation • bone revolves around its own axis • Special movements • uniquely named movements for jaw, hand and foot

30. Circumduction • Movement of a distal end of a body part in a circle • Combination of flexion, adduction , extension and abduction • Occurs at ball and socket, saddle and condyloid joints

31. Rotation • Bone revolves around its own longitudinal axis • medial rotation is turning of anterior surface in towards the midline • lateral rotation is turning of anterior surface away from the midline • At ball & socket and pivot type joints

32. Special Movements of Mandible • Elevation = upward • Depression = downward • Protraction = forward • Retraction = backward

33. Special Hand & Foot Movements • Inversion • Eversion • Dorsiflexion • Plantarflexion • Pronation • Supination