Human Anatomy - Joints - PDF

By: Dr. Ayman Ahmed Khanfour Professor of Anatomy & Embryology Master Degree in Obstetrics & Gynecology - MRCOG Faculty of Medicine - Alexandria University  Definition of a Joint Bone Bone Joint...

By: Dr. Ayman Ahmed Khanfour Professor of Anatomy & Embryology Master Degree in Obstetrics & Gynecology - MRCOG Faculty of Medicine - Alexandria University  Definition of a Joint Bone Bone Joint Bone  The joint is the point of meeting of two or more bones.  Classification  They are classified according to the substance between the ends of the bones into: A. Fibrous - The substance between the bones is “fibrous tissue”. B. Cartilaginous - The substance between the bones is “cartilage”. C. Synovial joints - The substance between the bones is “synovial fluid”.  Definition Bone Bone Fibrous Joint  The two bones are separated by “fibrous tissue”.  Types 1. Sutures - Example ----------- Sutures present between the bones of the skull. 2. Gomphosis (peg and socket) (‫)وﺗد وﺗﺟوﯾف‬ - Example ----------- Teeth and its socket. 3. Syndesmosis - Example ----------- Inferior tibiofibular joint (Types of the fibrous joints)  Characters  No movement is allowed.  Definition Bone Bone Cartilage  The two bones are separated by “cartilage”.  Types  According to the persistence of the cartilage, they are classified into: I. Primary cartilaginous joints II. Secondary cartilaginous joints  Primary Cartilaginous joints  A hyaline cartilage is present at the ends of long bones  This cartilage is transformed into bone (ossifies with growth).  No movement is allowed. Example: Epiphyseal plates of long bones  Secondary Cartilaginous joints  A fibro-cartilage is present at the ends of bones  This cartilage persists (it is not transformed into bone with growth).  Very limited movement is allowed. Example: Joints between bodies of vertebrae (intervertebral discs).  Definition Bone Bone Synovial fluid  The two bones are separated by “Synovial fluid”.  Characters 1. The articular surfaces of the bones are covered by hyaline cartilage. cartilage 2. They are covered by fibrous capsule which is thickened in some places to for ligaments. ligaments 3. The capsule is lined by synovial membrane which secretes “synovial fluid” fluid”. 4. The synovial joints have free movements such as joints of the upper and lower limbs. 5. There are intra-articular structures such as ligaments cartilage or cartilage.  Classifications Synovial joints Plane Uniaxial Biaxial Polyaxial 1. Plane (None axial) (just gliding movements) Example: Joints between the small bones of the hand and foot. (Gliding movement) (Example: Small bones of hand or foot) (Plane synovial joints & Animation) 2. Uni-axial (one axis of movement) i. Horizontal axis (hinge) Example: Elbow joint ii. Vertical axis (pivot) Example: Radio ulnar joint  (Elbow joint) (Radioulnar joints) (Horizontal axis) (Vertical axis) (Uniaxial synovial joints & Animation)  (Example: Knee joint) (Uniaxial synovial joints & Animation) 3. Bi-axial (two axes of movements) Example: Wrist joint  (Wrist joint) (Ellipsoid) (Biaxial synovial joints & Animation) 4. Poly-axial (multiple axes of movements) Example: Hip and shoulder joints. (Poly axial (Example: Hip joint) movement) (Polyaxial synovial joints & Animation)  Factors Affecting Stability of Joints 1. Bony factor: - It depends of the shape of the articulating bones. 2. Ligamentary factor: - It depends on the surrounding ligaments of the joint. 3. Muscular factor: - It depends on the surrounding muscles of the joint.  Applied Anatomy  Dislocation of joints usually occurs as a result of direct trauma to the joint (such as during car accidents). (Dislocation of shoulder joint) For Contact: Dr. Ayman Ahmed Khanfour [email protected] Dr. Ayman Khanfour Dr-Ayman Ahmed Khanfour Dr. Ayman Anatomy Discussion