Gross AnatomyGross Anatomy

“Big” and Really Cool

The SkeletonThe Skeleton206 BonesAxial: Skull,

Vertebral, Sternum, Ribs

Appendicular

General Features: Long BonesDiaphysis: Shaft, cylindrical

medullary cavity, Compact boneEpiphysis: Expanded Ends,

Cancellous BoneArticular Cartilage

More Features:More Features:Periosteum: Outside

membranous covering, dense connective tissue, blood vessels, nerves, osteoblasts

Endosteum: Medullary lining, osteoblasts

Movement MomentsMovement MomentsFlexion / ExtensionPlantar Flex / Dorsi Flex: FootPronate / Supinate: HandEversion / Inversion: FootAbduct /Adduct

HistologyHistology

Tissue Organization within Skeletal Bone

Tissue

Microscopic AnatomyMicroscopic Anatomy Compact:

“solid”, ~80% of the bone mass

Cancellous: “spongy”, 20%

Compact: TerminologyOsteon or Haversian System:

“Packed tree rings” around the Haversian canal (blood vessels)

Lamellae: “laminated” layersLacunae: “lakes” with osteocyte

“islandsCanaliculus: “Little canals”

Cancellous: TerminologyCancellous: TerminologyTrabecula: Networks of rods and

plates in spongy boneRed Marrow: Blood cell production

Children more abundantAdults: mostly axial, proximal

Yellow Marrow: Mostly Fat

The “Osteo” Cells:The “Osteo” Cells:Osteoblasts: perimeters of

the trabeculae or periosteum and endosteum of compact bone

Osteocytes: lacunae, “old blasts”

Osteoclasts: Perimeter

Bone Growth and Bone Growth and RemodelingRemodeling

Template: Model - FormTemplate: Model - FormOsteoblasts begin

depositing mineralized ECM in some type of connective tissue:Intramembranous: skull etcEndochondral: all other

bones

DirectionsDirections of bone of bone growthgrowthEndochondral: lengthening

ends with closure of epiphyseal plates

Appositional: widening - can continue throughout life

What?What?Endochondral or

Endochondral?Template

MaterialGrowth

Direction

Growth TermsGrowth TermsPrimary Ossification Centers:

Diaphysis, periosteum “collar”Secondary Ossification

Centers: Epiphyses, Epiphyseal Plates:

cartilagenous joints between Primary & Secondary centers

Assignment:Assignment:Check out on your Surface

IdentificationPredict Questions: Pages 114, 117,

149Open and Bookmark the following

website:eSkeleton: eSkeleton: http://www.eskeletons

.org/

Wrapping Up Skeletal Anatomy and Physiology

The JointsSynarthrosis:

Fibrous - immovable

Amphiarthrosis: Cartilaginous - some movement

Synovial Joints: CapsulesHighly

movable, Hinge, Pivot,

Saddle, Ball & Socket etc.

Structure /Function: Structure /Function: JointsJointsShape of articulating surfaces

determines range of motion (ROM) / Stability

Connective tissue influences ROM

Soft tissue influences ROM

Back Health - Vertebral Back Health - Vertebral ColumnColumnNormal Curves:

Cervical = anterior, Thoracic = posterior, Lumbar = anterior, Sacral = posterior

Functions: Balance, strength, and “shock absorption”

Excessive CurvesKyphosis: “Hunchback”Lordosis: “ Swayback”Scoliosis: Lateral curves

resulting in hip/shoulder uneveness

Bone RemodelingBone RemodelingMaintenance of Bone: Balance

between Osteoclasts vs Osteoblasts

Calcium demands vs. Calcium intake

Healthy bones = Osteoblast=/> than Osteoclast activity

Bone RepairBone RepairClot formation: ImmediateCallus formation: Beginning 2-

3 days after injuryCancellous Bone: Osteoblasts

invade callus - 4-6 weeks laterCompact bone: Replacing

Cancellous - months later

QuestionQuestion:Why do we immobilize

fractured bones?What are the negative

effects of prolonged immobilization?

Answer:Answer:To assist formation of good

callus, reduce painMuscle atrophy, joint

mobility, reduced stimulus to bone growth

And Now, A Movement Moment

Flex / ExtPronate /

SupinateEvert / InvertAbduct /AdductCircumduction