JOINT

1. JOINT • It is the site where two or more bones come together, where there is movement or not.

2. FIBROUS JOINTS • The articulating surfaces are joined by fibrous tissue. • Very little movement is possible. • E.G : • (1) Sutures of the vault of the skull. • (2) Inferior tibiofibular joints.

3. CARTILAGENOUS JOINTS • A. Primary Cartilagenous • The bones are united by a plate of hyaline cartilage. • E.G : • 1. Between the Epiphysis and Diaphysis of a growing bone. • 2. Between the first rib and the sternum.

4. CARTILAGENOUS JOINTS • B. SecondaryCartilagenous • The bones are united by a plate of fibrocartilage. • Their articulating surfaces are covered by a thin plate of hyaline cartilage. • E.G :(1)joints between the vertebral bodies. • (2) Symphysis pubis.

5. SYNOVIAL JOINT • It has a great degree of freedom of movement. • The articulating bones are covered by hyaline cartilage and separated by a joint cavity.

6. SYNOVIAL JOINT • The cavity is lined by synovial membrane. • It is protected on the outside by a tough fibrous capsule. • The synovial membrane produces a lubricating fluid(synovial fluid)

7. CLASSIFICATION OF SYNOVIAL JOINTS • 1. Plane: • The articulating surfaces are flat and the bones slide on one another. • E.G : • Sternoclavicular and Acromioclavicular joints.

8. CLASSIFICATION OF SYNOVIAL JOINTS • 2. Hinge : • It is a uni axial joint (E.G. Elbow, Knee and Ankle joints. • 3. Pivot : • A central bony pivot is surrounded by a bony ligamentous ring. • E.G. (Atlanto-axial, superior radioulnar ).

9. CLASSIFICATION OF SYNOVIAL JOINTS • 4. Condyloid : • Two convex articular surfaces articulate with two concave. (E.G.) Metacarpophalangeal (kunckle joints). • 5. Saddle : • The articulating surfaces are reciprocally concavoconvex. (E.G.) Carpometacarpal joint of the thumb.

10. CLASSIFICATION OF SYNOVIAL JOINTS • 6. Ellipsoid : • An elliptical convex articular surface fits into an elliptical concave one. • (E.G.) Wrist joint.

11. CLASSIFICATION OF SYNOVIAL JOINTS • 7. Ball and Socket • A ball –shaped head of one bone fits into a socket like concavity of another. • E.G. (Shoulder and Hip).

12. STABILITY OF THE JOINTS • 1.The Articular surfaces: shape, size and arrangement (E.G.) ball and socket of hip joint. • 2.Ligaments : • A.Fibrous : they prevent excessive movement in a joint. • If the stress is continuous for long, they become stretched. • (E.G.) ligaments between the bones forming the arches of the foot.

13. STABILITY OF THE JOINTS • B. Elastic : • The ligaments between ear ossicles have an important role in supporting the joints and return the bones to their original position.

14. STABILITY OF THE JOINTS • 3. Muscle tone : • In most joints it is the major factor controlling stability. • (E.G.) the muscles around the shoulder joint.

15. TERMS OF MOVEMENT • 1. Flexion : • It takes place in the sagittal plane. • It is usually an anterior movement. • 2. Extension : • It is straightening of the joint. • It takes place in a posterior direction.

16. TERMS OF MOVEMENT • Lateral flexion : • It is movement in the coronal plane.

17. TERMS OF MOVEMENT • 3. Abduction : • It is movement of a limb away from the midline of the body in the coronal plane. • 4. Adduction : • It is movement of a limb toward the body in the coronal plane. • 5. Circumduction : • It is the combination of flexion, extension,abduction and adduction.

18. TERMS OF MOVEMENT • 6. Medial rotation : • The anterior surface of the part faces medially. • 7. Lateral rotation: • The anterior surface of the part faces laterally.

19. TERMS OF MOVEMENT • 8. Pronation of the forearm: • It is medial rotation of the forearm so that the palm faces posteriorly. • 9. Supination of the forearm: • It is lateral rotation of the forearm so that the palm faces anteriorly.

20. TERMS OF MOVEMENT • 10. Planter flexion and Dorsiflexion of the foot. • 11.Inversion : • The sole faces in a medial direction. • 12.Eversion : • The sole faces in a lateral direction.