2nd Anatomy Lec. Cartilage & Bone PDF

Introduction to human Anatomy Marwa Abdel-Samad Al-Gholam MD Anatomy and Embryology Assistant Professor of Anatomy and Embryology Menoufia University  Objectives (Ilos) By the end of this lecture, the student should be able to:...

Introduction to human Anatomy Marwa Abdel-Samad Al-Gholam MD Anatomy and Embryology Assistant Professor of Anatomy and Embryology Menoufia University  Objectives (Ilos) By the end of this lecture, the student should be able to: Identify parts of the skeletal system List types of cartilage and differentiate between them List functions of bone Classify bone according to shape, structure, and development. Describe bone growth Cartilage and Bones The skeleton is composed of cartilage and bones. Cartilage is a semi-rigid connective tissue that forms parts of the skeleton where more flexibility is required: ❑At the sites of attachments of the ribs to the sternum. ❑Covering the articulating surfaces of bones in the synovial joints, provides smooth, gliding surfaces for free movement. Blood vessels do not enter cartilage (avascular tissue) and its cells obtain oxygen and nutrients by diffusion.  Translucent due to its very fine collagen fibers. Costal cartilage 1- Hyaline Yellow rich in elastic fibers. Auricle Epiglottis 2- Elastic White due to its high content of collagen fibres. Types of Intervertebral disc cartilage 3- Fibrocartilage  Bone ❑The hardest connective tissue in the body. ❑It is a highly vascular and shows a continuous turn over throughout life. FUNCTIONS OF BONE Assistance Support Protection for movement Storage for Blood cell minerals production The bony skeleton The bony Skeleton  4- Flat bone 1- Long bone 3- Irregular bone 2- Short bone Morphological (shape) classification of bone 5- Sesamoid bone  Morphological(shape) classification of bone Proximal epiphysis 1- Long bone ✓Tubular in shape ✓Two articular ends (Epiphysis) ✓Central medullary cavity Diaphysis Typical Long bone Distal epiphysis Humerus  Clavicle Modified long Bone Although designated as a long bone, the clavicle has no medullary (marrow) cavity  Short long Bone has a single epiphysis  2- Short bone ✓Cuboid in shape ✓ found only in the ankle (tarsus) and wrist (carpus). Tarsal Carpal  3- Flat bone ✓Usually serve protective functions ✓Provide extensive areas for muscle attachment. ✓Example: cranial (skull) bones, the sternum and the scapulae  4- Irregular bone Have various shapes other than long, short, or flat such as vertebrae. 5- Sesamoid bone They develop in certain tendons and are found where tendons cross the ends of long limb bones. Its name is derived from the Greek word for 'sesame seed' 6-Pneumatic bones: bones containing air spaces (sinuses). Certain cranial bones, such as maxilla and frontal bones  Structural classification of bone 1. Compact bone: is located at the surface of all bones, makes up the bulk of the diaphysis of long bones. 2. Spongy bone: is always located in the interior of a bone, protected by a covering of compact bone. Gross anatomy of the bone Short irregular and flat bone  Growing Long bone 1 5 2 Spongy 4 6 3 7 Epiphysis 8 9 Diaphysis 8 7 Epiphysis Metaphysis Metaphysis  1 1- Epiphysis 3 3- Metaphysis 2- Diaphysis 2 4 4- Periosteum 3 1 Parts of a growing long bone: 1. The epiphyses are the proximal and distal ends of the bone. 2. The diaphysis is the bone’s shaft, the long and cylindrical. 3. The metaphysis are the regions between the diaphysis and the epiphyses. It is highly vascular and an area of active growth 4. The periosteum is a tough connective tissue sheath and its associated blood supply that surrounds the bone surface except parts covered by articular cartilage.  Function of periosteum 1. Enable bone to grow in thickness. 2. Protects the bone. 3. Assists in fracture repair. 4. Helps nourish bone tissue 5. Serves as an attachment point for ligaments and tendons. 1-Periosteal arteries 2-Nutrient artery: □ It enters through the nutrient foramen. Towards the elbow I run and away from the knee I flee’. 3-The metaphyseal arteries. 4-The epiphyseal arteries.  Bone formation - Bone formation starts as early as the 5th week of intrauterine fetal life by the appearance of primary centers of ossification. - After birth, another generation of centers appears, the secondary centers of ossification. - Centers of ossifications appear on top of either connective tissue membranes or cartilaginous models and start bone formation.  Developmental classification of bone 2. Endochondral 1. bones or cartilage Intramembranous replacement bones bones  Developmental classification of bones Intra-membranous ossification Develop from a mesenchymal membrane. Begins in the fetal period As, bones of the face including the mandible and bones of the vault of the skull and clavicle.  Endochondral(Intra-cartilaginous) ossification The bone ossifies in a preformed model of cartilage, as ear ossicles, hyoid bone, and long bones of limbs. during the fetal period, bone subsequently replaces most of the cartilage  Growth of long bone: 1. Growth in length: by the activity of the epiphyseal plate involves two main stages: 1- Growth of cartilage 2- Replacement of cartilage with bone □ When full height is achieved the cartilaginous epiphyseal plate turns into bone and is indicated by the epiphyseal line. 2- Growth of bone in thickness: by subperiosteal deposition of bone tissue from periosteum. This process is known as appositional growth. Figure (27): Growth of bone in width. Regarding the following diagram, Which one is a sesamoid bone? a) A b) B c) C d) D e) E Short essay: 1- Draw with labeled diagram parts of growing long bone 2- Classify bone according to shape 3- List types of bone according to development 4- The epiphysis is the area of active growth in bone, justify.