Introduction to Human Anatomy PDF

INTRODUCTION TO HUMAN ANATOMY BY PROF.DR. ABEER EL-SAID EL-MEHI PROFESSOR OF ANATOMY AND EMBRYOLOGY FACULTY OF MEDICINE MENOUFIA UNIVERSITY SKELETAL SYSTEM (2) INTENDED LEARNING OUTCOMES: ✓TO DEFINE THE JOINTS AS PARTS OF SKELETAL SYSTEM. ✓TO CLASSIFY JOI...

INTRODUCTION TO HUMAN ANATOMY BY PROF.DR. ABEER EL-SAID EL-MEHI PROFESSOR OF ANATOMY AND EMBRYOLOGY FACULTY OF MEDICINE MENOUFIA UNIVERSITY SKELETAL SYSTEM (2) INTENDED LEARNING OUTCOMES: ✓TO DEFINE THE JOINTS AS PARTS OF SKELETAL SYSTEM. ✓TO CLASSIFY JOINTS FUNCTIONALLY AND STRUCTURALLY. ✓TO DIFFERENTIATE BETWEEN DIFFERENT TYPES OF JOINTS WITH EXAMPLES. ✓TO LIST THE FACTORS MAINTAINING JOINT STABILITY.  Joints A joint is the site of meeting of two or more skeletal elements whether a movement is allowed or not.  Classification of joints Functional Structural Is based on the focuses on the amount of movement material binding the allowed at the joint. bones together and Functionally, joints whether or not a joint are classified into: cavity is present. ✓ Immovable joints. Structurally, joints are ✓ Slightly movable classified into: joints. ✓ Fibrous joints. ✓ Freely movable ✓ Cartilaginous joints. joints. ✓ Synovial joints.  Fibrous joints ✓ The articulating surfaces are joined by fibrous tissue. ✓ They are fixed or have a little movement. ✓ They are three types : ▪ Sutures: between the bones of the skull. ▪ Syndesmosis: the articulating bones are connected by a sheet of fibrous tissue, either a ligament or a fibrous membrane e.g. inferior tibiofibular joint, middle radioulnar joint and middle tibiofibular joint. This type is joint is partially movable. ▪ Gomphosis : teeth in their sockets in the mandible and maxilla. The fibrous connection in this case is the periodontal ligament. Fibrous joints  Cartilaginous joints ✓ The articulating bones are joined by cartilage. ✓ They are fixed or have a little movement. ✓ They are two types : ▪ Primary cartilaginous joints: the bones are united by hyaline cartilage. Examples: epiphysial plate of cartilage in growing long bone & between the first rib and the manubrium sterni. ▪ Secondary cartilaginous joints: the bones are united by fibrocartilage. Examples: intervertebral joint, symphysis pubis & joints between parts of the sternum.  Synovial joints Characteristics of synovial joints: ✓ The articulating ends of the bones are covered by articular cartilage and separated by a joint cavity filled with synovial fluid. ✓ The joint is protected on the outside by a tough fibrous membrane; the capsule of the joint. ✓ The internal surface of the fibrous capsule is lined by synovial membrane. It lines whole of the interior of the joint, except for the articular surfaces covered by articular cartilage. ✓ The fibrous capsule is strengthened by ligaments. ✓ Intracapsular structures may be present ,e.g. discs and pad of fat. Axes of movements: Transverse axis Flexion & Extension. Anteroposterior axis Adduction & Abduction. Longitudinal axis Rotation.  Classification of synovial joints according to type of movement Uniaxial Biaxial Multiaxial Non – axial (Plane) Allow movements Allow movements Allow movements Allow gliding around one axis. around two axes. around multiple axes. movement.  Uniaxial synovial joints Hinge joints: ✓ Movement: flexion and extension around a single transverse axis. ✓ Examples: elbow, ankle, and interphalangeal joints (between the phalanges of the fingers and toes). Pivot joints: ✓ Movement: it allows rotation only around a single longitudinal axis. ✓ Examples: atlanto-axial and superior and inferior radioulnar joints. Interphalangeal  Biaxial synovial joints Condyloid joints: ✓ Movement: (flexion-extension and abduction–adduction) two axes, transverse and anterior posterior axes. ✓ Examples: wrist and metacarpophalangeal joints. Saddle joint: ✓ Movement: flexion–extension and abduction–adduction around two axes, transverse and anterior posterior axes. ✓ Examples: carpometacarpal joint of the thumb.  Polyaxial synovial joints Ball-and-Socket joints: ✓ Movement: (flexion–extension, abduction–adduction, and rotation) around three axes, (transverse ,anterior posterior and vertical axes). ✓ Examples: shoulder and hip joints.  Plane synovial joints ✓ Articular surfaces are flat. ✓ Movement: gliding ✓ Examples: intercarpal, intertarsal joints.  Stability of the joints Stability of the joint depends on : ✓ Shape of the articular surfaces ✓ Ligaments fixing the joint ✓ The muscles around the joint