Osteology. Dr. Carmen E. Rexach Anatomy 35 Mt San Antonio College

Transcription

1 Osteology Dr. Carmen E. Rexach Anatomy 35 Mt San Antonio College

2 Functions of the Skeletal System: Support Movement Protection Hemopoiesis Electrolyte balance (Ca ++ /PO -3 4 ) Acid-base balance Storage of heavy metals

3 General Classification of Individual Bones By shape Long Short Flat irregular

4 Long bones longer than wide have a marrow cavity Ex: femur, humerus Short bones Cube shaped Carpals and tarsal

5 Flat bones Broad surfaces for muscle attachment Enclose and protect soft organs Ex: roofing bones of skull, scapula, clavicle Irregular bones Varied shapes Prominent surfaces Ex: vertebrae, sphenoid bone

6 General Classification of Individual Bones by developmental location Sesamoid intramembranous development within a tendon Ex: patella Sutural (Wormian) intramembranous development within a suture

7 Composition of Long and Flat Bone Composition Compact (dense) outside Spongy (cancellous) inside Flat bones = diploë Long bones = trabeculae

8 Regions of long bone Diaphysis Epiphysis Medullary cavity Epiphyseal plate vs. epiphyseal line Periosteum Fibrous layer Osteogenic layer Sharpey s fibers Nutrient foramina Endosteum Articular cartilage

9 General anatomy of long and flat bone

10 Surface features: articular Facet smooth flat articulating surface Condyle smooth rounded articulating knob Head prominent condyle on a neck Anatomical neck Surgical neck anatomical surgical

11 Surface features: non-articular (prominences) Crest or line narrow ridge Tuberosity large roughened surface Epicondyle a roughened projection next to a condyle Tubercle small rounded rough process Trochanter massive roughened process (femur only) Process any marked bony prominence Spine a long slender process

12 Surface features: depressions/openings Fossa a flattened shallow depression Sulcus narrow, long groove Alveolus a socket (teeth) Sinus a cavity Meatus blind ended canal (temporal bone) Fissure a wide slit in bone Foramen (foramina) any opening in bone Canal long foramen

13 Surface Features

14 Surface Features

15 Histology of Osseous Tissue Connective Tissue Matrix Non-living ground substance, stuff Composition Cells 85% Hydroxyapatite crystals»ca 10 (PO 4 ) 6 (OH) 2 10% CaCO 3 Other minerals» Mg, Na, K, Fl, etc. collagen

16 Rickets and Osteomalacia

17 Cells Osteogenic line the inner periosteum produce new bone cells through mitosis Osteoblasts secrete matrix high metabolic rate Osteoblasts trapped in lacunae Osteocytes highly branched surrounded by matrix low metabolic rate Osteoclasts fixed macrophage Break down old bone cells bone lining cells line the surface of bones regulate calcium and phosphate passage

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20 On bone surface Multinucleated <150μm in diameter Use HCl to dissolve bone minerals

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23 Bone structure Compact bone Solid bone tissue Haversian system = osteon Concentric lamellae and central canal Lacunae, canaliculi Spongy (cancellous) bone First bone tissue to be laid down trabeculae = lattice of thin plates Spicules = rods and spines that fuse together to form trabeculae Porous, filled with bone marrow Arranged in lamellae, but few osteons Light weight + strength to bone

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26 Bone marrow Red Myeloid tissue Distribution in child vs. adult hematopoietic Yellow Fatty marrow replaces red bone marrow in adults Not hematopoietic, except in severe or chronic anemia Can revert back to red bone marrow

27 Development of Bones Ossification = osteogenesis deposition of bone tissue begins at approx 4 weeks gestation apparent at approx 10 weeks bone tissue arises as connective tissue from embryonic mesenchyme Two types Endochondral intramembraneous

28 Endochondral built on a hyaline cartilage model (perichondrium) ossification results in spongy bone first then an outer layer of compact bone 1 o in diaphysis, 2 o in epiphysis

29 Increasing the Diameter of Developing (Endochondral) Bone appositional growth on the outer surface osteogenic cells differentiate into osteoblasts matrix, blood vessels added to outer (periosteal) surface osteoclasts remove matrix at the endosteal surface marrow cavity enlarges as bone diameter enlarges

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31 Intramembranous Bone Development (dermal ossification) roofing bones of the skull, mandible, clavicle proceeds without a hyaline cartilage model bone tissue deposited between sheets of fibrous connective tissue spongy bone then outer layers of compact bone Diploe = spongy bone between 2 layers of compact bone

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37 Organization of the Skeleton (Major Divisions) Axial bones that form the axis of the body support and protect the organs of the head, neck and trunk Appendicular the bones of the upper and lower extremities + 2 bony girdles that attach the extremities to the axial skeleton

38 Number of bones: axial skeleton Structure Cranial Facial Auditory ossicles Hyoid Vertebral column Rib cage Total Fetus ± ±1 Adult ± ±1

39 Number of bones: appendicular skeleton Structure Pectoral girdle Upper extremities Pelvic girdle Lower extremities Total Total skeleton Fetus Adult