Skeletal System PA 544 Clinical Anatomy Dr. Tony Serino

Skeletal System Composed of mineralized CT and their supporting structures including: bone, cartilage, ligaments, tendons, and bursae Functions: support, protection, homeostasis (specifically Ca ++ regulation) and hempoiesis

General Osteology Composition Cells –originate from mesechyme (undifferentiated mesodermal cells) Extracellular Matrix –Ground substances: water, salts, cementing substances, glycoproteins –Fibers: collagen and elastin

Cartilage Avascular CT Appositional and interstitial growth possible Chondroblast Chondrocyte Perichondrium Lacuna Matrix

Hyaline Cartilage

Elastic Cartilage

Fibrocartilage

Cartilage in Adult

Bone Heavily mineralized CT Highly vascular Principle storage area of Calcium Provides strength and structural support to body

Long Bone Anatomy Fig. 6.3

Compact vs. Spongy Bone Trabeculae

Bone Histology Fig. 6.5

Haversian System Lamellae

Ossification Development of bony tissues First bone to form is woven (premature) bone This is eventually replace by mature bone (compact or spongy bone) Two methods for creating bones: –Intramembraneous (bone replaces mesoderm membrane) –Endochondral (bone replaces an intervening cartilage model)

Intramembranous Ossification (membrane bone)

Endochondral Ossification (replacement bone)

Epiphyseal (Growth) Plate Reserve Cartilage (distal perichondrium) Proliferating Cartilage (Growth zone) Hypertrophic zone (Transforming zone) Calcified matrix (Osteogenic zone)

Epiphyseal Plate

Fracture Healing

Osteoporosis Normal Osteoporotic

Divisions of Skeletal System Axial Skeleton Fig. 7.1

Appendicular Skeleton Fig. 7.21

Types of Bones Long Bones

Short Bones

Flat Bones

Irregular bones

Sesamoid Bones

Accessory Bones: Wormian (Sutural) Bones and other supernumerary bones Results from failure of separate ossifications centers to fuse (common in foot and hand) Heterotropic bones – arise in soft tissue where bones not normally present

Articulations Functional Classifications –Synarthrotic (immovable) –Amphiarthrotic (slightly movable) –Diarthrotic (movable) Structural Classification –Fibrous –held by fibrous tissue –Cartilaginous –held by cartilage –Synovial –synovial cavity within joint

Suture (synarthrotic, fibrous joint) Found in bones of skull

Gomphosis (synarthrotic, fibrous) Ligament cemented to tooth surface

Syndesmoses (amphiarthrotic, fibrous)

Synchondroses (Synarthrotic, cartilaginous) Epiphyseal Plate

Synchondroses (synarthrotic, cartilaginous)

Symphyses (amphiarthrotic, cartilaginous) Includes pubic symphysis

Synovial = diarthrotic joints The synovial membrane filters the blood to create synovial fluid This fluid lubricates and nourishes the joint Some joints may have an additional wedge of cartilage within the joint (menisci) Fig. 8.3

Bursae and Tendon sheaths

Arthritis