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
Bone Growth and Remodeling
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: eSkeleton:
Wrapping Up Skeletal Anatomy and Physiology
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 weeks later Compact bone: Replacing Cancellous - months later
Question 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