Introduction to Human Skeletal System

Introduction to Human Skeletal System

1. For the students of Gulf Medical University, Ajman, DMD Human Skeletal System Dr. Seyed Morteza Mahmoudi , MBBS Gulf Medical University, Ajman

2. At the end of the session students should be able to: 1) Name the parts of human skeleton 2) Identify and explain the purpose of some bones in the human skeleton 3) List the bones forming every part 4) Classify bones according to origin, shape and structure Objectives

3. Skeleton is a system made up of bones and cartilages and supported and supplemented by ligaments, tendons and muscles. It serves as a scaffold which supports organs, anchors muscles, and protects organs. Skeleton

4. What are Bones (Oss)? What are their functions?

5. Bone is a specialized connective tissue, consisting of cells, fibers and extracellular matrix. It’s a hard clacific , with adynamic structure. Functions: Mechanical Protection Movement Structure Sound transduction Synthetic, Hematopoiesis Metabolic Mineral storage Acid base balance Endocrine function Bone

6. 8 cranial 14 facial 6 ear bones H yoid bone 26 vertebrae (7 cervical, 12 thorax, 5 lumbar, the sacrum which is five fused vertebrae, and the coccyx which is four fused vertebrae) 24 ribs plus the sternum T he shoulder girdle (2 clavicles and 2 scapulae) T he pelvic girdle (2 fused bones) 30 bones in our arms and legs (a total of 120); Total No. 206 Total Number

7. Sex differences

8. How do we classify bones?

9. Classification of bones Contents Shape Development Structure Region

10. Shape

11. Long bones: Shaft with two ends Develop by intracartilagenous ossification Three centers of ossification Central medullary cavity Nutrient foramina E.g. humerus , ulna, femur etc. Short long bones: Shaft with one end Have two centers of ossification E.g. metacarpal and metatarsal bones Modified long bones: No medullary cavity E.g. clavicle Long bones

12. Have no shaft or ends Shape is cuboid, trapizoid or cuniform . Carpal and tarsl bones Short bones

13. Skull Ribs Sternum Scapula Flat bones

14. Irregular bones

15. Bone that contain air-filled spaces Pneumatic bones

16. Bony nodules embedded in tendons/ joints No periosteum and ossify after birth E.g. Patella, pisiform Sesamoid bones

17. Accessory bones

18. Classification of bones Contents Shape Development Structure Region

19. Development

20. All bones: mesodermal origin. Process of bone formation: ossification Ossification

21. Types of cells

22. Cartilaginous bones : ossify over a cartilagenous tissue: bones of limbs, vertebral column Membraneous bones: ossify over mesenchymal tissue: vault, facial bones Membrano -cartilaginous bones: partly from cartilage and partly from mesenchymal ossification: clavicle, mandible Developmental classification

23. Classification of bones Contents Shape Development Structure Region

24. Region

25. Classification of bones Contents Shape Development Structure Region

26. Structure

27. Parts of long bone

28. Parts of a long bone

29. Other

30. Diaphysis: shaft of a long bone which ossifies from primary center Epiphysis: ends and tips of bone which ossify from secondary centre Pressure epiphysis: articular and takes part in transmission of weight. Eg . Head of femur, lower end of radius Traction epiphysis: non articular- provides attachment of one or more tendons which exert a traction on epiphysis. These ossify later than the pressure epiphysis. Atavistic epiphysis: independent bone- which in man is fused to another bone- coracoid process of scapula Aberrant epiphysis: not always present- head of the 1 st metacarpal and base of the other metacarpals Parts of long bone

31. Epiphyseal plate of cartilage: separates epiphysis from metaphysis. Proliferation of cells in cartilage- lengthwise growth of a long bone Metaphysis: ends of diaphysis merging into the epiphysis. Zone of active growth. Richly supplied by blood vessels. Common site for osteomyelitis because of entrapment of bacteria and emboli in the bend of the blood vessels Parts of long bone (young)

32. Covering the long bone in all area, except the articular surfaces is periosteum . Deep to the periosteum is a layer of compact bone This layer is thicker in the diaphysis than the epiphysis Covering the articular surfaces is articular cartilage, or hyaline cartilage. Parts of long bone

33. In the diaphysis of the long bone deep to the compact bone is the medullary cavity. In the adult it is full of yellow bone marrow. The medullary cavity is lined with endosteom . In the epyphysis deep to the layer of compact bone is spongy bone. Between the trabacula of the spongy bone is red bone marrow. Parts of long bone

34. Nutrient artery Periosteal artery Epiphyseal artery Metaphyseal artery Blood supply of long bone

35. Thank you