Lecture 3 - Osteology PDF

KINE 2320 Kinesiological Anatomy Osteology: Fundamentals of the Skeletal System Reminders o Lab 1 this week o Weekend quizzes begin this weekend Skeletal System Osteology: Axial & Appendicular Skeletons o Adult skeleton o Axial skeleton o Appendicular (peripheral) o...

KINE 2320 Kinesiological Anatomy Osteology: Fundamentals of the Skeletal System Reminders o Lab 1 this week o Weekend quizzes begin this weekend Skeletal System Osteology: Axial & Appendicular Skeletons o Adult skeleton o Axial skeleton o Appendicular (peripheral) o Occasional variations in # of bones Bony Variation Example Skeletal Functions o Protection of heart, lungs, brain, etc. o Support to maintain posture o Movement by serving as points of attachment for muscles and acting as levers o Mineral storage such as calcium & phosphorus o Hemopoiesis – in vertebral bodies, femurs, humerus, ribs, & sternum Bone Types*** o Long bones o Short bones o Flat bones o Irregular bones o Sesamoid bones Long bones o Composed of a long cylindrical shaft with relatively wide, protruding ends o Shaft contains the medullary canal Short bones o Small, cubical shaped, solid bones o Usually have a proportionally large articular surface in order to articulate with more than one bone Flat bones o Usually have a curved surface & vary from thick where tendons attach to very thin Irregular bones o Include bones throughout entire spine, pelvis & maxilla Sesamoid bones o Includes patella and two at the first metatarsophalangeal Typical Bony Features o Diaphysis o Epiphysis o Metaphyses o Periosteum o Endosteum o Medullary cavity o Articular cartilage Bone regions o Diaphysis o Shaft or body of the bone o Epiphysis o End of long bones formed from cancelleous (spongy or trabecular) bone o Metaphyses o Region where the diaphysis joins the epiphysis Bone regions o Periosteum (peri= around; osteo= bone) o Dense, white fibrous membrane covering outer surface of diaphysis o Outer fibrous layer o Dense, irregular connective tissue o Blood vessels, lymphatic vessels, nerves that go to the bone o Inner osteogenic layer o Contains elastic fibres, blood vessels, and various types of bone cells o Protects, repairs, nourishes bone o Attachment for tendons and ligaments Bone regions o Cortex o Hard, dense compact bone forming walls of diaphysis o Endosteum (endo = within) o Fibrous membrane that lines the medullary cavity o Contains osteoprogenitor cells and osteoclasts o Medullary cavity (medulla = central part) o Between the walls of the diaphysis o Contains the fatty yellow bone marrow Bone Composition and Structure o Mineral salts (Inorganic components) o Rigidity o Most of dry weight o Organic components o Collagen fibers (type I, 90% of the extracellular matrix) o Flexibility and strength/resilience in resisting tension o Water Bone Properties o Most outer bone is cortical with cancellous underneath o Cortical bone* o Low porosity o 5 to 30% non-mineralized tissue o Can withstand greater stress, but less strain o Cancellous bone* o High porosity o 30 to 90% non-mineralized tissue o Can undergo greater strain before fracturing Bone Properties o Wolff’s Law: o Bones reshape themselves based upon the stresses placed upon them: o ↑ stress = ↑ mass Osgood-Schlatter Disease Articular (hyaline) cartilage o Layer of hyaline cartilage over epiphysis o Reduces friction and absorbs shocks o Also provides flexibility and support o Bluish white o Shiny ground substance with fine collagen fibers o Most abundant type of cartilage Articular Cartilage Composition & Structure o Articular cartilage has a high level of structural organization o Chondrocytes o Sparsely distributed o Extracellular matrix o Network of fine collagen fibrils o A concentrated solution of Proteoglycans o Other o Water, inorganic salts, other matrix proteins, glycoproteins, lipids o 60 to 85% net weight  Articular Cartilage Organization 1. Superficial Tangential Zone o Fine, densely packed fibers parallel to the articular surface 2. Middle Zone o Randomly oriented and homogeneously dispersed fibers 3. Deep Zone o Forms larger, radially oriented fiber bundles that cross tidemark Articular Cartilage Organization Water in Articular Cartilage o Most abundant component of articular cartilage o ~80% concentrated near the articular surface o 65% in the deep zone o Most of the water occupies the inter-fibrillar space of the extra-cellular matrix and is free to move when a load or pressure gradient is applied. o In compression: ~70% water may be moved o Decreases with age Molecular Organization of the Articular Cartilage o Interactions form a material that is: o Porous, permeable o Water flows in and out o Fiber-reinforced solid matrix swollen with water and ions Bone Growth: Endochondral Bones o Develop from hyaline cartilage o Hyaline cartilage masses at embryonic stage o Grow rapidly into bone-like structures Epiphyseal plate (Growth Plate) o Thin cartilage plate o Separates diaphysis & epiphyses Slipped epiphyseal plate Bone Growth o Longitudinal growth continues while epiphyseal plates are open o Shortly after adolescence, plates close & disappear o Most close by age 18 o Growth in diameter continues throughout life Bone Growth o Internal layer of periosteum builds new concentric layers on old layers o Simultaneously, bone around sides of the medullary cavity is resorbed so that diameter is continually increased o Osteoblasts - cells that form new bone o Osteoclasts - cells that resorb old bone Common Bone Markings o Joints o Condyle o Attachments o Facet o Angle o Head o Border o Crest o Cavities o Epicondyle o Facet o Line o Foramen o Process o Fossa o Spine o Fovea o Trochanter o Notch o Tubercle o Sinus o Tuberosity o Groove Joint Processes Form joints o Condyle o Facet o Head Attachment Processes For Ligament, Muscle, Tendon o Crest o Epicondyle o Line o Process o Spine o Suture o Trochanter o Tubercle o Tuberosity Cavity Processes Depressions (openings & grooves o Facet o Foramen o Fossa o Fovea o e.g., femur o Meatus o e.g., ear o Sinus o e.g., face o Sulcus (groove) o e.g., pre-auricular sulcus on ileum