2 anatomy 1 lec2 _241230_040449.PDF

The Joints Def. :The sites of meeting between two bones or more are called joints. Not all joints permit movements. The joints are classified into three types; According to the type of the material that binds the forming bones A. Fibrous joints: the articular surfaces of the bones are bounded togeth...

The Joints Def. :The sites of meeting between two bones or more are called joints. Not all joints permit movements. The joints are classified into three types; According to the type of the material that binds the forming bones A. Fibrous joints: the articular surfaces of the bones are bounded together by fibrous tissue. Very little movement can be allowed. The fibrous joints are subdivided into three types : 1- Sutures: the bones of the skull sutures (serrated borders) and attached to each other by fibrous ligaments (sutural ligaments). 2- Gomphosis (peg and socket): limited to the teeth to fix them in their sockets in alveolar margins of the jaw. 3-Syndesmosis: interosseous ligament and membranes like between ulna & radius. @Sinaiunieg [email protected] www.su.edu.eg @Sinaiunieg [email protected] www.su.edu.eg  Primary cartilaginous joints Secondary cartilaginous joints Cartilage type Hyaline Fibrocarilage Duration Temporary Permanent Movement No movement Little movement Examples Epiphyseal plate of long bone Cartilaginous Joints in midline e.g. intervertebral discs @Sinaiunieg [email protected] www.su.edu.eg @Sinaiunieg [email protected] www.su.edu.eg C. Synovial joints: Characters 1- The articular surfaces are covered by hyaline cartilage. 2- It has a fibrous capsule enclosing a joint cavity. 3- The capsule is lined by synovial membrane. 4- The joint cavity contains a film of serous fluid called synovial fluid secreted by the synovial membrane to lubricate the articular surfaces. 5- The joint is supported by a number of ligaments 6- These joints have a wide range of movements @Sinaiunieg [email protected] www.su.edu.eg Classification of synovial joints: According to degree of movement: 1- Plane joints: the articular surfaces are flat. Slight gliding or sliding movements only can be allowed e.g. intercarpal and intertarsal joints. 2- Angular joints: joints that permit movements and form angles between the articulating bones (flexion and extension) e.g. ankle, knee joints 3- Circumduction: joints that permit successive angular movement e.g. hip and shoulder joints. @Sinaiunieg [email protected] www.su.edu.eg  According to the articular parts: 1- Simple joints: only 2 bones articulated with each other e.g. shoulder and hip joints 2- Compound joints: more than 2 bones articulated with each other e.g.elbow or ankle joints 3- Complex joints: bones articulated with presence of intra-articular structure.e.g knee joint According to the axis of movements: 1- Uniaxial joints: a- Hinge joint: these joints resemble a hinge of a door. It moves along transverse axis. It permits flexion and extension only e.g. elbow joint. b- Pivot joint: These joints move along a longitudinal axis and allow rotation only e.g. superior and inferior radio- ulnar joints @Sinaiunieg [email protected] www.su.edu.eg HINGE JOINT PIVOT JOINT 2- Biaxial joints: A- Ellipsoid: an elliptical convex surface is received into an elliptical concave one. It allows flexion and extension, and adduction and abduction. Rotation in this type is impossible e.g. wrist joint. B- Condyloid joints: two convex articular surfaces articulate with two concave articular surfaces. Movements of flexion and extension and a minimal degree of rotation are allowed e.g. knee joint @Sinaiunieg [email protected] www.su.edu.eg ELLIPSOID JOINT CONDYLOD JOINT C- Saddle shaped: Each of the articular surfaces is concavo-convex. The convexity of one surface is received into the concavity of the other one and vice versa. It resemble a saddle on the back of a horse e.g. carpometacarpal joint of the thumb. 3- Polyaxial (Ball and socket) joints: a ball shaped head of one bone is received into a socket-like concavity of another bone. This type permits flexion and extension, abduction and adduction, medial and lateral rotation and circumduction. The examples of this type are the hip and the shoulder joints. @Sinaiunieg [email protected] www.su.edu.eg SADDLE JOINT BALL & SOCKET JOINT - Bursa These are closed fibrous sacs, lined internally with delicate smooth membranes resembling the synovial membrane. They contain a film of serous fluid. They are present between the tendons and the bone or between the tendons and ligaments and the sites where the skin rubs against the bone adjacent to the joints The function of the bursa is to lubricate the movement and minimize friction. @Sinaiunieg [email protected] www.su.edu.eg THANK YOU For any questions feel free to contact me by mail [email protected] Dr. Dalia El-wafaey Associate professor of Anatomy & Embryology 24