The Skeletal System

Newborn Baby= 350 bones Fusion of bones Mature Adult= 206 bones

Purposes of the bones of the Skeletal System: Provide a framework for the body Protect vital organs (brain, spinal cord) Serve as levers, when muscles are attached, to help us lift and move Store calcium, which may be reabsorbed into the blood if there is not enough calcium in the diet Produce blood cells in the red bone marrow

Bones Five most common categories: Long Short Flat Irregular Sesamoid

Long bones Form legs and arms (humerus, femur) Parts of long bones: Shaft (diaphysis): longest portion Compact bone: solid, outer layer Epiphysis: end of the bone that is shaped to connect to other bones (using ligaments and muscles) Spongy bone: layer inside the compact bone that covers the space in which marrow is stored

Short bones Small, cube-shaped bones of the wrists, ankles and toes Outer layer of compact bone Inner layer of cellous bone- bone with a latticework structure

Flat bones Large, flat surfaces Cover organs Provide a surface for large areas of muscle Shoulder blades, pelvis, skull

Irregular bones Specialized bones with specific shapes Ears, vertebrae, face

Sesamoid bones Formed in a tendon near joints Patella (kneecap) Also found in hands and feet

Extensions and depressions Serve as sites for attaching muscles and tendons Ex: greater trochanter-bony extension near upper end of femur

Bone marrow Soft connective tissue Production of blood cells Red Bone Marrow: infant bones and flat bones of adults; where red blood cells (RBC’s) start to develop Yellow Bone Marrow: in most other adult bones; made of connective tissue filled with fat

Bones of the Head Sutures: points where skull or cranial bones join

Bones of the Spinal Column Five segments of vertebrae Each separated by a cartilaginous disc Space between vertebral body and back= spinal cord

Cervical: 7 Thoracic: 12 Lumbar: 5 Sacrum: 5 at birth, fuse in adulthood Coccyx: 4 fused bones

Bones of the Chest Clavicle Scapula Sternum Xyphoid Process Ribs: True Ribs (7) False Ribs (3) Floating Ribs (2)

Bones of the Pelvis Pubic Symphysis Pelvic Girdle Ilium Ischium Pubis

Bones of the Extremeties Arm: Humerus Radius Ulna Carpals Metacarpals Phalanges

Bones of the Extremeties Leg: Femur Tibia Fibula Tarsals Calcaneus Metatarsals Phalanges

Joints: Points where bones connect Bones connect to other bones using ligaments Ligaments: bands of fibrous tissue Movement of joint depends on the body’s need

Diarthroses: joints that move freely

Amphiarthroses: Cartilaginous Joints that move slightly

Synarthroses: Joints that do not move; Join bones firmly

Synovial Joints: (another name for diarthroses) Joints covered with a membrane that secretes a fluid lubricant to help the joint move easily

Fractures Breaks or cracks in bones Types: Closed: break with no open wound Simple (hairline): fracture, does not move any part of the bone out of place Open (compound fracture): break with an open wound

Fractures, cot’d Types: Greenstick (incomplete): incomplete bone break Comminuted: break in which the bone is fragmented or shattered Colles’: break of the lower end of the radius Complicated: fracture with extensive soft tissue injury

Fractures, cot’d Types: Impacted: fragment from one part of a fracture is driven into the tissue of another part Compression: break in one or more vertebrae caused by a compressing or squeezing between the vertebrae Spiral: occurs when a bone is twisted apart

Diseases of the Skeletal System Osteoporosis: softening of the bones due to lack of calcium Occurs most often in post- menopausal women Loss of bone density and easily broken bones

Osteomyelitis: bacteria in the bone tissue Severe pain at the end of the bone Bone damage Diseases of the Skeletal System

Arthritis: inflammation of the joints Pain, stiffness, aching Limited range of motion Range of motion: measurement of the degree to which a joint is capable of moving Osteo- and rheumatoid arthritis Diseases of the Skeletal System

Sprain: injury or trauma to the joints that tears ligaments Pain, swelling, tenderness, inability to move the area Usually heal within two weeks Diseases of the Skeletal System

Herniated Disc: one or more of the spinal discs balloon out from inside the bony parts of the vertebrae Can cause unbearable pain if pressing on a nerve Diseases of the Skeletal System

Posture/Spinal Conditions Kyphosis: humpback, rounding forward of the thoracic vertebrae Lordosis: swayback; abnormal inward curvature of the lumbar vertebrae Scoliosis: side-to-side curvature of the spine