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Gross Anatomy. “Big” and Really Cool. The Skeleton. 206 Bones Axial: Skull, Vertebral, Sternum, Ribs Appendicular. General Features: Long Bones. Diaphysis : Shaft, cylindrical medullary cavity, Compact bone Epiphysis : Expanded Ends, Cancellous Bone Articular Cartilage. More Features:.
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Gross Anatomy “Big” and Really Cool
The Skeleton • 206 Bones • Axial: Skull, Vertebral, Sternum, Ribs • Appendicular
General Features: Long Bones • Diaphysis: Shaft, cylindrical medullary cavity, Compact bone • Epiphysis: Expanded Ends, Cancellous Bone • Articular Cartilage
More Features: • Periosteum: Outside membranous covering, dense connective tissue, blood vessels, nerves, osteoblasts • Endosteum: Medullary lining, osteoblasts
Movement Moments • Flexion / Extension • Plantar Flex / Dorsi Flex: Foot • Pronate / Supinate: Hand • Eversion / Inversion: Foot • Abduct /Adduct
Histology Tissue Organization within Skeletal Bone Tissue
Microscopic Anatomy • Compact: “solid”, ~80% of the bone mass • Cancellous: “spongy”, 20%
Compact: Terminology • Osteon or Haversian System: “Packed tree rings” around the Haversian canal (blood vessels) • Lamellae: “laminated” layers • Lacunae: “lakes” with osteocyte “islands • Canaliculus: “Little canals”
Cancellous: Terminology • Trabecula: Networks of rods and plates in spongy bone • Red Marrow: Blood cell production • Children more abundant • Adults: mostly axial, proximal • Yellow Marrow: Mostly Fat
The “Osteo” Cells: • Osteoblasts: perimeters of the trabeculae or periosteum and endosteum of compact bone • Osteocytes: lacunae, “old blasts” • Osteoclasts: Perimeter
Template: Model - Form • Osteoblasts begin depositing mineralized ECM in some type of connective tissue: • Intramembranous: skull etc • Endochondral: all other bones
Directions of bone growth • Endochondral: lengthening ends with closure of epiphyseal plates • Appositional: widening - can continue throughout life
What? • Endochondral or Endochondral? • Template Material • Growth Direction
Growth Terms • Primary Ossification Centers: Diaphysis, periosteum “collar” • Secondary Ossification Centers: Epiphyses, • Epiphyseal Plates: cartilagenous joints between Primary & Secondary centers
Assignment: • Check out on your Surface Identification • Predict Questions: Pages 114, 117, 149 • Open and Bookmark the following website: • eSkeleton: http://www.eskeletons.org/
The Joints • Synarthrosis: Fibrous - immovable • Amphiarthrosis: Cartilaginous - some movement
Synovial Joints: Capsules • Highly movable, • Hinge, Pivot, Saddle, Ball & Socket etc.
Structure /Function: Joints • Shape of articulating surfaces determines range of motion (ROM) / Stability • Connective tissue influences ROM • Soft tissue influences ROM
Back Health - Vertebral Column • Normal Curves: • Cervical = anterior, • Thoracic = posterior, • Lumbar = anterior, • Sacral = posterior • Functions: Balance, strength, and “shock absorption”
Excessive Curves • Kyphosis: “Hunchback” • Lordosis: “ Swayback” • Scoliosis: Lateral curves resulting in hip/shoulder uneveness
Bone Remodeling • Maintenance of Bone: Balance between Osteoclasts vs Osteoblasts • Calcium demands vs. Calcium intake • Healthy bones = Osteoblast=/> than Osteoclast activity
Bone Repair • Clot formation: Immediate • Callus formation: Beginning 2-3 days after injury • Cancellous Bone: Osteoblasts invade callus - 4-6 weeks later • Compact bone: Replacing Cancellous - months later
Question: • Why do we immobilize fractured bones? • What are the negative effects of prolonged immobilization?
Answer: • To assist formation of good callus, reduce pain • Muscle atrophy, joint mobility, reduced stimulus to bone growth
And Now, A Movement Moment • Flex / Ext • Pronate / Supinate • Evert / Invert • Abduct /Adduct • Circumduction