Kaan Yücel M.D., Ph.D .

1. INTRODUCTION TO OSTEOLOGY BONES 03. February. 2014 Monday Kaan Yücel M.D., Ph.D.

2. .INTRODUCTION TO OSTEOLOGY Osteology (Gk, osteon, bone, logos, science) branch of medicine concerned with the development and diseases of bone tissue The human skeleton 206 bones in adults

3. The skeletal system may be divided into • 2functional parts: • The axial skeleton • head (cranium or skull) • neck (hyoid bone and cervical vertebrae) • trunk (ribs, sternum, vertebrae, and sacrum) • The appendicular skeleton • Limbs • including those forming the shoulder & pelvic girdles

4. Bone one of the hardest structures of the animal body calcification of its extracellular matrix some elasticity results from the organic matter great rigidity results from their lamellous structures and tubes of inorganic calcium phosphate colorin a fresh state pinkish-whiteexternally, deep red within.

5. HISTOLOGY OF THE BONE sparse cells surrounded by an extracellular network/matrix

6. Osteoblasts secrete proteins into the matrix.

7. Mature bone is composed of proteins and minerals. 60% the weight of the bone mineral Rest- water & matrix. 90% of the matrix proteins collagen1/3 of the bone weight very strong forms bone, cartilage, skin, and tendons. High resolution image of cortical bone and single collagen fibril (inset)

8. Mineralsof the matrix Mainlycalcium phosphate & calcium carbonate Embedded in the protein network Providehardness and compressive strength.

9. Matrix maintained by osteocytes Haversiansystems or osteons concentric rings of osteocytes arranged around a central blood vessel.

10. Principal types of bone cells Osteogenic cells Osteoblasts Osteocytes Osteoclasts

11. Periosteum membranesurroundingthe bone tissue provides a routeforthevasculatureandnervesupply. participates in bone growthandrepair. Endosteum linesthe marrow cavity active during bone growth, repair, and remodeling covers trabeculaeof spongy bone lines the inner surfaces of the central canals

12. CartilageSand Bones • The skeleton is composed of cartilages and bones. • Cartilage • resilient, semirigid form of connective tissue • forms parts of the skeleton where more flexibility is required. articulating of bones participating in a synovial joint capped with articular cartilage provides smooth, low-friction, gliding surfaces for free movement

13. Blood vessels do not enter cartilage avascular • Diffusion • bone /cartilage in the skeleton • changes as the body grows • younger a person the more cartilage • bones of a newborn are soft and flexible because mostly composed of cartilage.

14. CartilageSand Bones The skeleton is composed of cartilages and bones. The amount and kind of extracellular fibers in the matrix depends on the type of cartilage. Heavyweightbearing areas or areas prone to pulling forces Morecollagenfibers, lessflexiblecartilage.

15. Functionsof cartilage support soft tissues provide a smooth, gliding surface for bone articulations at joints enable the development and growth of long bones.

16. Typesof cartilage • 1. Hyaline • most common,matrix w/ moderate amount of collagen fibers articularsurfaces of bones • 2. Elastic • large number of elastic fibers external ear • 3. Fibrocartilage • limited number of cells &ground substance amidst substantial amount of collagen fibers intervertebral discs

17. Bones function as • supportive structures for the body • protectors of vital organs • reservoirs of calcium and phosphorus • levers on which muscles act to produce movement • containers for blood-producing cells

18. TYPES OF BONES • according to their shape gross anatomy • Long bones • tubular humerusin the arm • 3)Flat bones • protectivefunctions • flat bones of the cranium protect the brain • 2)Short bones • cuboidal • tarsus (ankle) carpus (wrist)

19. Classification of Bones • 4) Irregular bones • various shapes other than long, short, or flat • bones of the face

20. Classification of Bones • 5) Sesamoidbones • patella or knee cap • protect the tendons from excessive wear • often change the angle of the tendons as they pass to their attachments.

21. Long bones develop by replacement of hyaline cartilage plate endochondral ossification a shaft diaphysis - two ends epiphyses Metaphysis a part of the diaphysis adjacent to the epiphyses. Diaphysisencloses the marrow cavity.

22. 2types of bones according to histological features compact bone &spongy (trabecular) bone relative amount of solid matter #&size of the spaces they contain

23. All bones have a superficial thin layer of compact bone • around a central mass of spongy bone • except where the spongy boneis replaced by a medullary (marrow) cavity. • Spongy bone • found @ expanded heads of long bones +fills most irregular bones. • Compact bone • forms outer shell of all bones+shafts in long bones.

24. Bone Markings and Formations • Bone markings appear wherever tendons, ligaments, and fascias are attached or where arteries lie adjacent to or enter bones. • Other formations occur in relation to the passage of a tendon (often to direct the tendon or improve its leverage) or to control the type of movement occurring at a joint.

25. Bone Markings and Formations • Surfaces of the bones are not smooth. • Bones display elevations, depressions and holes. • The surface features on the bones are given names to distinguish and define them.

26. Vasculature and Innervation of Bones • Bones are richly supplied with blood vessels. • Veins accompany arteries. • Nerves accompany blood vessels supplying bones.