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skeletal system21-22.pptx
- 1. Bones • Specialized connectivetissue • Has mineralized extracellular matrix • Has more regeneration capacity (second to blood) • Has 206 bones
- 2. Bones • Provides • Basicshape & support • Mechanical base of movement • Muscular system acts on • To produce movement • Store house for salts (eg. calcium) • Production unit for blood cells (Hematopoiesis) • Protects • Vital organs • Brain & spinal cord • Heart • Lungs • Pelvic organs
- 3. Bones - classification •4 types of classification • Position • Shape & size • Structure • Ossification
- 4. According to position •Axial - Lie along the central axis of the body • Appendicular – lie in the extremities (upper & lower limbs)
- 5. • Axial (80) •Skull • - Cranial bones (8) • Parietal (2) • Temporal (2) • Frontal (1) • Occipital (1) • Ethmoid (1) • Sphenoid (1) • -Facial bones (14) • Maxilla (2) • Zygomatic (2) • Mandible (1) • Nasal (2) • Platine (2) • Inferior nasal concha (2) • Lacrimal (2) • Vomer (1) • Auditory ossicles (6) • Malleus (2) • Incus (2) • Stapes (2) • Vertebral column (26) • Cervical vertebrae (7) • Thoracic vertebrae (12) • Lumbar vertebrae (5) • Sacrum (1) • Coccyx (1) • Thoracic Cage (25) • Sternum (1) • Ribs (24) • Hyoid bone (1)
- 6. • Pelvic Girdle(2) • Hip bones (2) • Lower Extremity (60) • Femur (2) • Tibia (2) • Fibula (2) • Patella (2) • Tarsals (14) • Metatarsals (10) • Phalanges (28) Appendicular Skeleton (126 bones) • Pectoral girdles (4) • Clavicle (2) • Scapula (2) • Upper Extremity (60) • Humerus (2) • Radius (2) • Ulna (2) • Carpals (16) • Metacarpals (10) • Phalanges (28)
- 7. According to theirshape • Long • Short • Flat • Irregular • Pneumatic • Sesamoid • Accessory
- 8. Long bones • Has •2 ends • One shaft • Medullary cavity • Except clavicle • Cartilaginous type of ossification • Except clavicle (membranous) • Nutrient foramen • Directs away from growing end • Types • Long bones • Eg., limb bones (humerus, femur…) • Miniature long bones • Has one end • Eg. Metatarsals and metacarpals
- 9. Long bones -parts • Diaphysis • Shaft • Epiphysis • Ends of long bone • Metaphysis • Lies between • Diaphysis & epiphysis • Has • Growth plate
- 10. Epiphysis • Part ofthe bone • Ossified from secondary ossification centre • Formed after birth • Exception – lower end of femur
- 11. Epiphysis - types •Pressure • Transmission of body weights • Eg. Ends of long bones • Traction • By muscular pull • Eg., Greater & lesser trochanter & tuberosities • Atavistic • Morphologically different bone in lower form • Higher form unites with other bone • Eg., Coracoid process of scapula • Aberrant epiphysis • Not always • Head of first metacarpal and bases of other metacarpals
- 12. Metaphysis • Epiphyseal endof diaphysis • Of young growing bone • Growing region of diaphysis • Vascular zone of growing bone • Blood vessels form hair pin bend • Infection in a long bone starts from this site • Condition known as osteomyelitis in children • Weak due to • Stress & strain • Due to attachment of • Muscles, ligaments & capsule
- 13. Blood supply –long bones • 4 sets of vessels • Nutrient artery • Metaphyseal artery • Hair pin bend – osteomyelitis • Epiphysial artery • Periosteal aretey
- 14. Short bones • Cubicalin shape • Have six surfaces • 4 surfaces are articular • Carpals & tarsals Carpals Tarsals
- 15. Flat bones • Has2 outer plates of compact bone • Spongy bone lies within it • Examples: scapula, ribs, sternum and vault of skull
- 16. Sesamoid bone • Seedlike bone • Formed in the tendons of muscles • Formed after birth • Peculiarities • No periosteum • No haversian system • Significance • Resist the pressure • Alter the direction of the pull of the muscle • Decrease the friction • Maintain the local circulation • May have bursa • Articular surface have articular cartilage
- 17. Sesamoid bone • Patella– tendon of quadriceps femoris • Pisiform – flexor carpi ulnaris • Fabella – lateral head of gastrocnemius • Riders – adductor longus tendon • Below first metatarsal – flexor hallucis brevis • Cuboid – peroneus longus
- 18. Pneumatic bones • Irregularbones • Contains air cavities • Function • Make skull lighter • Helps in resonance of voic • Act as airconditioner • Humidifies and warms the inspiring air • Sites • Maxilla. Frontal, Sphenoid and Ethmoid
- 19.
- 20. According to bonytissue • Compact bone • All bones have a superficial thin layer – around thin mass • Spongy bone • Central mass • Small needle-like pieces of bone • Many open spaces • In adult lies between • Compact bone and • Medullary cavity
- 21. Bone structure • Periosteum •Endosteum • Medullary cavity • Compact bone • Spongy bone
- 22. Bones - structure •Periosteum • Thick fibrous membrane • Forms outer surface of bone • Except articular surface • Has two layers • Outer fibrous • Inner cellular • Osteoblasts • Sharpey’s fibres (Perforating) • Helps in blood supply • Gives attachment to muscles, tendons & ligaments • Endosteum • Vascular membrane • Lines the medullary cavity • Osteoclast cells are found close
- 23. Bones – structure •Medullary cavity - Bone marrow • Soft vascular tissue • Lies in medullary cavity • 2 types • Red bone marrow • Blood cell forming marrow • Found in middle & young bone & flat bone • Yellow marrow • Fat tissue replaces red bone marrow • Applied anatomy • Leukemia (cancer of the blood cells) • Bone marrow starts to make a lot of abnormal white blood cells
- 24. Bones – structure •Compact bone • Made of Haversian systems in longitudinal • Haversian system (osteon) consists • Haversian canal • Surrounded by Concentric lamellae • Lacunae present • Interstitial lamellae • Circumferential lamellae • Volkman’s canal
- 25. Haversian system (osteon) •Haversian canal • Runs in longitudinal axis of bone • Contains nerves, vessels (blood & lymphatic) • Surrounded by Concentric lamellae • Layers of calcified bone matrix • Lacunae present • Contains osteocytes • Canaliculai • Fine channels interconnecting the lacunae and Haversian canal • Interstitial lamellae • Lies in the intervals between osteons • Circumferential lamellae • Volkman’s canal • Oblique canals running at right angles to the long axis of bone • Connect the haversian canal with the medullary cavity and surface of bone
- 26. Spongy bone • Poorlyorganized trabeculae (small needle-like pieces of bone) • Have large spaces
- 28. Components of bone •2 components • Bone cells • Inter cellular substance (Matrix)
- 29. Bone cells • Osteogeniccells • Resting cells • Found in external & internal surface • Osteoblasts • Bone forming cells • Derived from mesenchyme • Secrete inorganic matrix (synthesis of osteoid & its mineralization) • May become osteocyte, osteoclast (fused osteoblasts) • Osteocytes • Matured bone cells • Located in lacunae • Osteoclasts • Mutinucleated cells • Bone destroying cells • Lie resorption bays (Howship lacunae)
- 30. Intercellular substance • 2parts • Organic • Collagen • Cement substance • Mucoprotein, glycoprotein, mucopolysaccharides etc., • Inorganic • Calcium, magnesium, phosphate, citrate etc.,
- 31. Ossification • Process ofbone formation • Proliferation of collagen and ground substance • Subsequently deposition of calcium • Types • Intramembranous • Mesenchyme directly converted into bone • Eg., Clavicle, Vault of skull and flat bones • Intracartilaginous • Mesenchyme first becomes cartilaginous model • Cartilaginous model replaced by bone tissue
- 32. Centre of ossification •From which point ossification starts • 2 types • Primary ossification center • Which appears first usually before birth • Diaphysis of long bones • Exception: In carpal & Tarsal after birth • Except – Talus, Cuboid and Calcaneus • Secondary ossification center • Which appears after birth • Epiphysis (ends) of long bones • Except: lower end of femur and upper end of tibia
- 33. Laws of ossification •Secondary ossification centre • Where two secondary centres present • The centre which appears first unites last • Exception: Fibula • Nutrient foramen • Always away from growing end of bone • Growing end of bone • If there are two ends • Ossification in one end appears first • Grows longer and fuses later
- 34. Bone markings –gross features • How made • Attachments of • Tendons, ligaments and fascia • Passage of • Tendon, vessels and nerves
- 35. Bone markings –gross features Commonly used terms • Condyle – articular area (round) • Crest - ridge • Epicondyle – eminence superior to condyle (non articular) • Facet – flat smooth area • Foramen - opening • Fossa - depression • Groove - linear depression • Line – linear elevation • Malleolus – rounded projection • Notch - indentation • Protuberance - projection • Spine – thorn like projection • Spinous process • Trochanter – large elevation • Tubercle – small elevation • Tuberosity – large rounded elevation