The Skeletal System

Skeletal System

Functions of the skeletal system Framework Support/protect internal organs Body movement Provides leverage for lifting and movement Produces RBCs and some WBCs Stores majority of body’s calcium supply

Bone Composition & Growth Osteoblasts: Cells in bone tissue produce new cells Osteoclasts: Cells that break bone cells down Re-absorb

Bone Tissue Compact bone Hard dense part of bone Cancellous Loosely packed or spongy

Accessory Structures Cartilage: Fibrous connective tissue On end surfaces to prevent friction Ligaments Sheet of fibrous connective tissue Attaches bone to bone Tendons Fibrous connective tissue Attaches muscle to bone

Axial skeleton Consists of Skull Spinal column Ribs Sternum

Appendicular skeleton Upper extremities Shoulder Arms Forearms Wrists Hands Lower extremities Hips Thighs Legs Ankles feet Pelvis

Four groups of bone Long Length is greater than the width Femur Short Blocky bones Similar length/width Wrist (carpal) and ankle (tarsal ) bones

Four groups of bone Flat Composed of two layers compact bone with spongy bone between them scapula and skull Irregular Bones of complex shape and structure Facial and vertebrae bones

Bones of the Skull Cranium(skull) : encloses the brain Frontal forehead Parietal Roof and upper sides of cranium Occipital Posterior floor and walls of cranium Temporal Sides and base of cranium

Bones of the Skull Mandible Lower jaw bone Only moveable bone Maxilla Upper jaw bone

Thorax Rib cage Ribs Sternum Thoracic vertebra True ribs Attached to sternum False ribs Attached to ribs above Floating ribs Attached to vertebrae only

Spinal Column Vertebral column 26 vertebrae Types of vertebrae Cervical-7  neck Thoracic-12  Chest Lumbar-5  Lower back  Largest and strongest

Spinal Column Sacrum Triangular shaped Base of spine Coccyx Tail bone End of spine

Structures of the Long Bone

Structures of bones Long Bone Diaphysis Long shaft of bone Epiphysis Ends of long bone Medullary canal Cavity w/in long bone Contains either yellow or red marrow

Structures of bones Tissues of a bone Periosteum Outer covering of bone Layer promote bone growth nutrition, and repair Endosteum Lines medullary canal

Structures of bones Bone marrow Red bone marrow Manufactures RBCs & WBCs Ribs, sternum, vertebrae, scapula, long bones Yellow bone marrow Functions as fat storage

Blood cells Erythrocytes Carry O2 and CO2 Leukocytes Fight infection Thrombocytes clotting

Joints Articulation and Movement

Joints Two or more bones join together Three types of joints: Immovable (synarthrosis) Cranium Slightly movable (amphiarthrosis) Pelvis Freely movable (diarthrosis) Elbows, knees, hips, shoulders, ankles

Freely Moveable Joints (Synovial) Freely movable Pivot joint Allow rotation on single axis Base of skull Ball and socket wide range of movement in many directions Hips and shoulders Hinge joints Allows movement in one direction or plane (bend and straighten) Knees and elbows

Freely Moveable Joints  Saddle joint  Convex and concave surface fit together  Thumb  Gliding joint  Two surfaces meet with motion limited by tissues and ligaments  Wrist and ankle

Synovial fluid Lubrication for joints smooth movement of joints Acts as shock absorber Meniscus Fluid-filled disc Reduces friction Bursa Sac lined with synovial membrane Reduces friction

Disorders of the Skeletal System

Disorders of the Skeletal System Osteomyelitis Severe inflammation of bone and bone marrow Cause: bacterial infection Osteoporosis Calcium and phosphorous deficiencies Bones porous and fracture easily Occurs in mainly in women as they age

Disorders of the Skeletal System Arthritis Inflammation of the joint Bursitis Inflammation of the bursa

Disorders of the Skeletal System Gout Accumulation of uric acid crystals in a joint

Disorders of the Skeletal System Dislocation Separation of a joint Sprain Injury to soft tissues of a joint Symptoms: inability to move, deformity, and pain

Disorders of the Skeletal System Fractures Disruption of the bone tissue

Fractures Incomplete fracture Fracture line does not extend through bone Complete fracture Fracture lines goes all the way through bone

Fractures Comminuted fractures Bone broken in several places and splinters of bone can be embedded in surrounding tissue

Fractures Compression fracture Bone collapses due to disruption of bone tissue Usually in vertebrae

Fractures Greenstick fracture Incomplete break that occurs almost exclusively in children Hairline fracture in adults

Fractures Compound: Causes disruption of skin and soft tissue Fragment of bone punctures skin Often complicated by infection

Fracture treatment Reduction of fractures Manipulation to restore correct anatomical position

Fracture treatment Open reduction  surgical incision to expose fracture site  Bone realigned and position with internal fixation (rods, plates, screws) Closed reduction  Local or general anesthesia may be used  Manipulate bone back into normal position

Fracture treatment Immobilization with a cast or splint Alleviates muscle spasm around fracture site

Tractions Applies to a pin inserted through distal bone fragment and pulling forces helps return overriding fragments to normal anatomical position Used until healing takes place or Until internal fixation can be performed

The End