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Axial skeleton bones of the skull, vertebral column, and rib cage80 bones make up the Axial SkeletonAppendicular skeleton bones of the upper and lower limbs, shoulder, and hip126 bones of the Appendicular skeleton
Support form the framework that supports the body and cradles soft organsProtection provide a protective case for the brain, spinal cord, and vital organsMovement provide levers for musclesMineral storage reservoir for minerals, especially calcium and phosphorusBlood cell formation hematopoiesis occurs within the marrow cavities of bones
Long bones longer than they are wide (e.g., humerus)Short bonesCube-shaped bones of the wrist and ankleSesamoid- Bones that form within tendons (e.g., patella)Flat bones thin, flattened, and a bit curved (e.g., sternum, and most skull bones)Irregular bones bones with complicated shapes (e.g., vertebrae and hip bones)
General FactsThe skull is made of 22 bones: 8 cranial, 13 facial, mandibleThere are 206 individual bones in an adult. Some are hinged and others are fused to one anotherThe upper jaw (maxillae) is fused to the cranium. The lower jaw (mandible) is moveable.The infant skull is incompletely developed and features fontanels or soft spots to aid passage thru the birth canal and allow for growth of the brain.
General Facts continued. . . The vertebrate is made of:7 cervical vertebrae12 thoracic vertebrae5 massive lumbar vertebraeSacrum, which is a triangular bone made of 5 fused bones at the end of the vertebral column.Coccyx, which is made up of 4 fused bones at the end of the sacrum (tailbone). It is immovable in humans, but flexible in cats, dogs, and monkeys
General Facts continued. . . There are 12 pairs of ribs which attach to the sternum thru the thoracic vertebrae. the first 7 pairs of ribs are true (or vertebrosternal) ribs that join the sternum directly by their costal cartilages.the remaining 5 ribs are false ribs: the first 3 pairs are vertebrochondral ribs and the last 2 pairs are floating ribs.Bones grow from the growth plates in the epiphyseal disks
Bones grow from the growth plates in the epiphyseal disks
Bones thicken with weight bearing exerciseLack of exercise leads to bone atrophyVitamin D necessary to absorb calcium for bone strengthVitamin C necessary for collagen Vitamin A necessary for bone growth
Tutorial on Bones of the Skull
Periosteum double-layered protective membraneOuter fibrous layer is dense regular connective tissueInner osteogenic layer is composed of osteoblasts and osteoclastsRichly supplied with nerve fibers, blood, and lymphatic vessels, which enter the bone via nutrient foraminaSecured to underlying bone by Sharpeys fibersEndosteum delicate membrane covering internal surfaces of bone
Marrow:-Yellow: Located in the center of the diaphysis in the medullar canal. Made mostly of fat cells, contains many blood vessels, some leukocytes (WBC). Functions as a fat storage center.-Red: Located at the ends of the long bones. Where some erythrocytes (RBC) and WBCs are made.
Compact bone dense outer layer. Makes up the walls of the diaphysis.Spongy bone honeycomb of trabeculae filled with yellow bone marrow. Fills the epiphyses to reduce the weight of the skeleton.
Long bones consist of a diaphysis and an epiphysisDiaphysisTubular shaft that forms the axis of long bonesComposed of compact bone that surrounds the medullary cavityYellow bone marrow (fat) is contained in the medullary cavity
EpiphysesExpanded ends of long bonesExterior is compact bone, and the interior is spongy boneJoint surface is covered with articular (hyaline) cartilageEpiphyseal line separates the diaphysis from the epiphyses
Osteocytes mature bone cellsLacunae small cavities in bone that contain osteocytesCanaliculi hairlike canals that connect lacunae to each other and the central canal
Haversian system, or osteon the structural unit of compact boneLamella weight-bearing, column-like matrix tubes composed mainly of collagenHaversian, or central canal central channel containing blood vessels and nervesVolkmanns canals channels lying at right angles to the central canal, connecting blood and nerve supply of the periosteum to that of the Haversian canal
Osteoporosis- reduction in bone mineral density which leads to fracturesFracturesCancerScoliosis- curvature of the spineRickets Caused by lack of vitamin D in childrenBone wasting or atrophy
10 Types of FracturesCompression Fracture: bone crushed; common in the vertebral columnComminuted fracture: most commonly seen in the brittle bones of the elderlyCompound fracture: fracture in which the bone ends penetrate the skinClosed reduction: non-surgical realignment of broken bone ends and splinting of the bone.Depressed fracture: common fracture of the skull in which the bones become concave
10 Types of Fractures (cont.)Simple fracture: bone is cleanly broken and does not penetrate the skin; commonly called a closed fractureImpacted fracture: fracture in which the broken ends are pushed into each otherOpen fracture: fracture that required surgical realignment of the broken bone endsGreenstick fracture: common in children; bone splinters but doesnt break completely; sometimes referred to as a hairline fractureSpiral fracture: bone breaks due to twisting forces: common in sports injuries
Closed reductioncompoundOpen reduction