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SKELETAL SYSTEM 206 BONES MAKE UP THE HUMAN SKELETON 2 TYPES OF BONE 1. Compact bone- (hard, dense outer area) densely packed matrix of salts and collagen- nourishment provided to bone cells by blood vessels that extend through Haversian canals 2. Spongy bone –not as densely packedcontain spaces that are filled with bloodcalled red marrow Matrix is deposited in thin, bony plates called spicules around the red marrow 2 skeletons AXIAL SKELETON- used mostly for protection- bones of the skull, vertebrae, ribs and sternum APPENDICULAR SKELETON-used mostly for support and movement- bones of the hip and legs, also the shoulder and arms Bone tissue OSTEON or HAVERSIAN SYSTEM- complete ring consisting of osteocytes, lamallae and a central Haversian canal BONE TISSUE Bone-“osseous tissue” “OSTEOCYTE” - Mature bone Cell located in LACUNAE- a hollow cavity LAMELLAE- Lacunae are arranged in concentric rings of calcium salts HAVERSIAN CANAL- (it consists of blood vessels and nerves)one central “bullseye” CANALICULI- tiny squiggly lines “canals” radiating outward from the central Haversian Canal- to all the lacunae in the osteon. This is how nourishment gets to each osteocyte. Bone tissue PERFORATING “VOLKMANN’S” CANALS- blood vessels that travel at right angles to the direction of the shaft go from the exterior of the bone to the interior and reach the Haversian canals 4 TYPES OF BONES 1. LONG BONE- longer than they are wide- have a shaft with heads at both ends- all the bones of the limbs (femur, humerus, ulna, etc)- made mostly of COMPACT bone 4 TYPES OF BONES 2. SHORT BONEtypically cube shaped- mostly SPONGY bone- bones of the wrist and ankle, patella 4 TYPES OF BONES 3. FLAT BONE- thin, flattened, and usually curved – contain two thin layers of compact bone sandwiching a layer of spongy bone- 4 TYPES OF BONES 4. IRREGULAR BONEbones that do not fit any of the above categories(vertebrae, hip bones) PARTS OF LONG BONE EPIPHYSES- the ends of the long bonescomposed of a thin layer of compact bone surrounding spongy boneDIAPHYSIS- the shaft of the bonecomposed of compact bone PERIOSTEUM – connective tissue covering of the shaft of the long bone that nourishes the bone ENDOSTEUM- inner lining of the bone cavity PARTS OF LONG BONE YELLOW MARROW-found in the MEDULLARY CAVITY- The cavity of the shaft is primarily a storage area of fat. RED MARROW - found in the cavities of spongy bone and the epiphyses of long bones (found in long bones in infants) PARTS OF LONG BONE EPIPHYSEAL PLATE- flat plate of hyaline cartilage seen in young, growing bone. Cause the bone to grow length wise. This cartilage plate gets replaces by bone at the end of puberty and leaves only an EPIPHYSEAL LINE to mark their previous location ARTICULAR CARTILAGE- hyaline cartilage that covers the epiphyses- provides a smooth, slippery surface for a joint. Functions of BONE (5) 1. 2. 3. 4. Support Protection- (ex.- skull and ribcage) Movement- attachment places for muscles and used as levers Storage1. Minerals- calcium and phosphorus 2. Fat- yellow bone marrow Functions of BONE (5) 5. HEMATOPOIESIS- the formation of blood cells (both RBC and WBC) occurs in the red bone marrow BONE MARKINGS PROJECTIONS THAT HELP FORM JOINTS Head Facet Condyle Ramus BONE MARKINGS PROJECTIONS FOR MUSCLE AND LIGAMENT ATTACHMENT Tuberosity Trochanter Tubercle Process Crest Line Spine Epicondyle DEPRESSIONS AND OPENINGS FOR THE PASSAGE BLOOD VESSELS AND NERVES Meatus Sinus Fossa Groove Fissure Foramen AXIAL SKELETON SKULL- is formed by two sets of bones. CRANIUM BONES- 8 bones that enclose the brain FACIAL BONES- 15 bones of the face and jaw SUTURES- immovable joints between bones Cranium Cranium from superior view Facial Bones from MANDIBLE FUSED VERTEBRAE First 5- Form the SACRUM Last 4 – Form the COCCYX or tailbone VERTEBRAL COLUMN 33 SEPARATE BONES9 BONES WILL EVENTUALLY FUSE TOGETHER 24 non fused vertebrae 1ST 7 VERTEBRAECERVICAL (NECK) Next 12 VERTEBRAETHORACIC (contains ribs) Last 5 VERTEBRAELUMBAR ( lower back) TYPICAL VERTEBRAE BODY- large section for weight bearing VERTEBRAL FORAMENopening for spinal cord SPINOUS PROCESSsingle spine at the posterior of the vertebrae TYPICAL VERTEBRAE VERTEBRAL ARCH- the whole loop around the vertebral foramen- (consists of Lamina and Pedicle) TRANSVERSE PROCESSlateral projections from the vertebral arch TYPICAL VERTEBRAE SUPERIOR ARTICULAR PROCESS- where it forms a joint with the vertebrae above INFERIOR ARTICULAR PROCESS-where it forms a joint with the vertebrae below CERVICAL VERTEBRAE 1st vertebrae- ATLAS- articulates with occipital condyles- (atlas has no BODY) - allows you to nod your head “YES” 2nd vertebrae- AXIS- has a large superior process (ODONTOID PROCESS or DENS) which acts as a pivot - allows you to rotate your head “NO” CERVICAL VERTEBRAE THORACIC VERTEBRA LUMBAR VERTEBRA BONY THORAX thoracic cage” Includes 1. 2. 3. around the lungs and heart. thoracic vertebrae ribs sternum RIBS- 12 pairs attach to the thoracic vertebra 7 pairs of TRUE RIBS which attach directly to the sternum by COSTAL CARTILAGE 5 pairs of FALSE RIBS- which attach indirectly or not at all to the Sternum 1 pair of FLOATING RIBS- which are the last set of false ribs which lack any attachment to the sternum STERNUM STERNUM- flat bone that is attached to the first 7 ribs. The result of the fusion of three bones 1. MANUBRIUM (top) 2. BODY (middle) 3. XIPHOID PROCESS (point on bottom) 3 LANDMARKS OF THE STERNUM 1. JUGULAR NOTCH- concave upper border of the manubrium 2 STERNAL ANGLE- fusion of the manubrium and the body. Meets at a slight angle. Located at the second rib and is a reference point 3. XIPHISTERNAL JOINT- point where the sternal body and xiphoid process fuselocated at the 9th thoracic vertebrae SPINE CURVATURES SCOLIOSIS- spine is out of alignment longitudinally “S shaped” KYPHOSIS- extreme curvature of thoracic vertebrae “hunchback” LORDOSIS- extreme curvature of lumbar vertebrae Problems RICKETS- disease in children in which bones fail to calcify. Rickets is typically due to lack of calcium in the diet or lack of vitamin D which is needed for bone absorption OSTEOPOROSIS- disease typically of older women- where bone tissue breaks down faster than new bone tissue is built up TYPES OF FRACTURES Common Types of Fractures SIMPLE /CLOSED- fracture that does not break the skin COMPOUND / OPEN- fracture that breaks through the skin TYPES OF FRACTURES Types of reductions CLOSED REDUCTION- putting the bone back in alignment without surgery OPEN REDUCTION- surgery is needed to hold the bones in place with pins / wires Other Types of Fractures COMMINUTED- bone breaks into many fragments. Common in elderly (osteoporosis). Causes- car crashes, major accidents COMPRESSION- bone is crushed. Common in elderly (osteoporosis) and Vertebrae. Usually from falling from serious heights DEPRESSED- bone broken inwards- Skull fracture due to blunt force trauma TYPES OF FRACTURES Other Types of Fractures IMPACTED- broken bone ends forced against each other- Common in falls from large heights SPIRAL- ragged break occurs from excessive twisting. Common sports injury GREENSTICK- bone breaks incompletelycommon in children’s bones which are more flexible OSSIFICATION- the formation of bone tissue (Pg 121) OSSIFICATION- involves 2 typeslengthening and widening OSTEOBLASTS- bone-forming cells -form the bone matrix OSTEOCLASTS- bone destroying cells break down old bone Widening Osteoblasts in the periosteum add bone tissue to the external surface of the bone while OSTEOCLASTS break down bone from the inner surface of the diaphysis wall. (endosteum) Lengthening-Epiphyseal plates account lengthening. 1. New cartilage is formed continuously on the external surface of the epiphyseal plate 2 Internal surface of epiphyseal plate is being broken down and turned to bony matrix by osteoblasts. 3 When the osteoblasts catch up and turn all the epiphyseal plate to bone- growth stops. REMODELING- bones are living and constantly changing Due to: 1. CALCIUM levels in the blood, PARATHYROID HORMONE breaks down bone when its needed for calcium in the blood. CALCITONIN- (made in the thyroid) lowers calcium levels in the blood by producing more bone (storage) 2. Stresses by muscle pull and gravity determine where bone matrix is broken down or formed (larger projections for increased muscle mass) OSSIFICATION- Page 121 In embryos, the skeleton is primarily made of HYALINE CARTILAGE which acts as a model. 2. A Bony Matrix of OSTEOBLASTS made by the PERIOSTEUM, completely surrounds the hyaline cartilage along the diaphysis. “BONY COLLAR STAGE” 1. 3. PRIMARY OSSIFICATION- blood vessel penetrates to center of diaphysis where osteoblasts turn hyaline cartilage to bone 4. SECONDARY OSSIFICATION- blood vessels penetrate epiphysis where osteoblasts turn hyaline cartilage to spongy bone 5. Center of diaphysis (endosteum) is then eaten away by osteoclasts creating the Medullary cavity. (The hyaline cartilage is replaced by bone by the time you are a young child except for Articular Cartilage (which will never turn to bone) and the Epiphyseal plates) 4 EVENTS OF BONE REPAIR 1 HEMOTOMA- blood filled swelling, pain, heat In the inflammation stage, hematoma and hemorrhage formation results from the disruption of periosteal and endosteal blood vessels at the site of injury. The open ends of these vessels undergo thrombosis. Macrophages, leukocytes and other inflammatory cells invade the area 4 EVENTS OF BONE REPAIR 2. FIBROCARTILAGE CALLUS- form granulation tissue around injury site In the primary soft callus formation stage, the cells that are stimulated to produce new vessels, fibroblasts, intracellular material and supporting cells. They form granulation tissue in the space between the fracture fragments. After that, macrophages, giant cells and other wandering cells arise in granulation tissue to invade and remove it . This stage lasts for about 2 weeks and clinically corresponds to the time when clinical union is established by fibrous or cartilaginous tissue. 4 EVENTS OF BONE REPAIR 3. BONY CALLUS- osteoblasts migrate to area to form bone form cartilage callus The mineralization of soft callus begins about 1 week later, after the formation of new soft callus. Increased oxygenation to increase stability of callus. The formation is dependent on the relative stability of the fracture fragments. The more motion there is at a fracture site, the larger callus is needed to prevent this motion . When stability and strength have been gained across the fracture site, the patient may resume limited activity. The creation and mineralization of callus may take anything from 4 to 16 weeks and is a quicker process in children and in spongy bone (Crenshaw 1992). 4 EVENTS OF BONE REPAIR 4. BONY CALLUS IS REMODELED in response to mechanical stress and forms a permanent patch The callus remodellation stage consists primarily of the replacement of callus with packets of new bone..Local vascular supply, oxygenation and pH all revert to normal.. The callus between the ends of compact bone is replaced by secondary osteons composed of lamellar bone.. The bone then first produces osteoclasts that remove a packet of pre-existing hard tissue and then produce osteoblasts that replace it with a packet of newly made bone. Complete replacement of callus with functionally competent lamellar bone by remodeling one to four years TYPES OF JOINTS (ARTICULATIONS) Joints can be classified in two ways. Functionally and structurally FUNCTIONAL 1. SYNARTHROSES- immovable 2. AMPHIARTHROSES- slightly movable 3. DIARTHROSES- freely movable STRUCTURAL CLASSIFICATIONS 1. FIBROUS – connected by fibrous tissuesutures of the skull (synarthrotic) 2. CARTILAGINOUS- connected by fibrocartilage or hyaline cartilage-vertebrae- Pubic symphysis- (usually AMPHIARTHROTIC 3. SYNOVIAL- joints with a cavity containing synovial fluid (DIARTHROTIC) 4 features of synovial joints 1. 2. 3. 4. ARTICULAR CARTILAGE-(hyaline cartilage on end of bone) FIBROUS ARTICULAR CAPSULE- fibrous connective tissue lined with synovial membranes encloses the joint JOINT CAVITY- filled with synovial fluid REINFORCING LIGAMENTS- 4 features of synovial joints BURSA SACS- tiny sacs of lubricating fluidthat act like “ball bearings” (can become inflammed- BURSITIS often called water on the knee) TENDON SHEATH- bursa sac that wraps around a tendon to protect it Type of synovial joints 1. Ball and Socket – head of one bone fits into cavity of another bone-such as the shoulder or the hip and femur. (MULTIAXIAL) 2. Hinge - one bone can hinge in a trough shaped area of another bone-such as the elbow, ankle, and phalanges (UNIAXIAL) 3. Pivot – allows one bone to rotate around another, such as the atlas and axis , also the radius and ulna. (UNIAXIAL) Type of synovial joints 4. Condyloid “knucklelike” – one egg shaped surface fits into an oval concavity- allows movement from side to side and up and down but no rotation- such as the wrist between radius and carpals, or knee (BIAXIAL) 5. Saddle – each bone has a convex and concave shape-such as the joint between carpal and metacarpal of the thumbs. (BIAXIAL) 6. Plane- gliding movement across each other, carpals (NONAXIAL)