Skeletal System

Skeletal SystemSkeletal TissueSkeletal TissueOsseous tissue

Made up of inorganic compounds like calcium and phosphorousGive hardness and rigidity

Made up of organic compounds like cartilageGive small amount of flexibility, to stop from easily breakingSkeletal TissueTypes of BonesLong BonesFemur, humerusShort BonesCarpals and tarsalsFlat bonesScapulae, ribs, sternumIrregular bonesSphenoidSesamoid bones- irregular bones that appear singularly like the patella

Parts Of A Long BoneDiaphysis- main part of bone, compact boneEpiphysis- ends of long bone, cancellous boneAt development epiphysis is separated from the diaphysis by a thick layer of cartilage called the epiphyseal plate (where mitosis occurs)Articular Cartilage- hyaline cartilage that covers epiphysisPeriosteum- fibrous connective tissue that covers bone except at articulationsMedullary cavity- hollow tube in diaphysis, in adults its filled with yellow marrowEndosteum- lines the medullary cavity of long bones

Microscopic AnatomyCompact BoneOsteocytes are found in lacunaeLacunae are arranged in circles called lamellaeLamellae are formed around Haversian canalCanaliculi radiate to all lacunae and act as a transportation system

Microscopic AnatomyCancellous BoneDoesnt contain Haversian SystemInstead has trabeculae where bone cells are foundSite of red marrow and hematopoesis

Bone CellsOsteoblastsBuild up boneOsteoclastsErode bone (break it down)OsteocytesMature osteoblasts that no longer have functionRegulation of Blood Calcium LevelsBones store 98% of body calciumCalcium levels must be maintained for bone formation, blood clotting, nerve impulses and skeletal and cardiac muscle contractionControlled by two hormones: parathyroid hormone and caclitoninParathyroid hormone: When blood calcium is low, hormone is stimulated, activating osteoclasts. Bone will be broken down and calcium will enter blood. When blood calcium levels are too high, PTH will be supressed, reducing amount of calcium that enters blood streamCalcitonin- activated by high levels of blood calcium, stimulates osteoblasts activity, decreases osteoclast activityPTH is main hormone involved in calcium regulation Development of BoneOssification- bone formationSkeleton begins as hyaline cartilage but then turns into bone (for all bones except flat bones)Cartilage is covered by bones (osteoblasts) and then cartilage is eaten away, forming medullary cavity

Repair of Bone FractureBlood at injury site forms a clotCallus tissue forms, binding bones togetherBone remodeling then takes place

Skeletal SystemBone MarkingsBone MarkingsAngle-cornerBody-main part of boneCondyle-rounded bumpCrest- raised ridge, usually a place for muscle attachmentEpicondyle- bump near condyl (muscle attachment)Facet- flat surface that forms a joint w/ a flat boneFissure-long, thin hole for blood vessels and nervesForamen- round holeFossa-depression, receives articulating boneHead-distinct epiphysis on long boneLine- more faint than crestMargin-edge of flat boneMeatus-tubelike opening or channelNeck-narrow portion, usually at end of headNotch-V like margin at edge of flat areaProcess- raised area of projectionRamus-curved portion of boneSinus-cavity within a boneSpine-raised more than a crestSulcus-elongated depressionTrochanter- large bump for muscle attachment (largest of the bumps)Tuberosity-oblong raised bump for muscle attachmentFunctions of Skeletal SystemProtectionMovementMineral StorageBlood Cell FormationSupportSkeletal SystemAxial SkeletonAxial SkeletonForms longitudinal axis of bodyFace and SkullVertebral ColumnBony Thorax (chest)

SkullCranium- 8 bonesFace- 14 bones

CraniumComposed of eight flat bones

Except for two paired bones (parietal and temporal) the rest are single bones

Frontal, 2 Parietal, 2 Temporal, Occipital, Sphenoid, Ethmoid

FrontalForehead boneSupraorbital marginSupraorbital foramenGlabella

ParietalForm top sides of cranial cavity

TemporalForm lower sides of craniumMastoid processExternal auditory meatusStyloid process

OccipitalPosterior part of craniumForamen magnum

SphenoidButterfly shaped boneSpans width of skull and forms floor of cranial cavitySella turcica/Turks saddle- holds pituitary gland in place

EthmoidLies anterior to sphenoidForms roof of nasal cavity and medial walls of orbitsCrista galli- process

FontanelsSkeleton is unfinished at birthFontanels are areas where hyaline cartilage hasnt ossified in skullCalled soft spotsAnterior fontanel (largest)Closes at 18 monthsPosterior fontanel (2nd largest)2monthsMastoid fontanelBegins to close 1 month after birth, not complete until 1yrSphenoid fontanelCloses by 3 months

SuturesInterlocking, immovable joints that hold all but one of facial bones togetherSaggital sutureSeperates parietal bonesLamboidal sutureOccipital and parietalSquamousSeperates temporal and parietalCoronalSeperates parietal and frontal

Bones of the faceComposed of 14 bones

All are paired but 2

Nasal (2), Maxillary (2), Zygomatic (2), Mandible (1), Lacrimal (2), Palatine (2), Inferior nasal conchae (2), Vomer (1)

Inferior Nasal ConchaeBone that forms shelf along inner surface of sidewall of nasal cavity

Serves to filter air and bring it to body temp

PalantineL shaped

Forms posterior part of hard palateNasalSmall bones that form bridge of nose

MaxillaArticulates with every bone of face except mandibleIf palantine process and maxilla bones dont unite before birth, a cleft palate will result

ZygomaticCheek bone

MandibleLargest and strongest of facial bonesOnly moveable bone in faceMental foramen- site of anesthetics administered by dentist

LacrimalSmallest bone of the faceResembles shape and size of fingernail, helps form sidewall of nasal cavity

VomerTriangular bone forms the inferior and posterior parts of the nasal septum

Bones of the earTwo sets of 3 bones (one set/ear)

Malleus (hammer)

Incus (anvil)

Stapes (stirrup)

In SummaryTotal # of bones of skull 288 Cranial bones14 Facial boens6 Ear bonesBones that make up the orbitEthmoidLacrimalMaxillaryFrontalSphenoidZygomaticPalentineHyoidSingle bone of neck

U shaped

Above larynx but below mandible

Does not form a joint with any other bone in body

Vertebral Column24 vertebrae + sacrum + coccyx

70cm (28 in)

Cervical vertebrae=7

Thoracic vertebrae=12

Lumbar vertebrae=5

Typical VertebraeAll are similar but have slight differences in size, shape and detailBodyVertebral ArchPedicles, laminae, vertebral foramen, intervertebral foraminaProcesses7 arise from the vertebral archTransverse will extend laterally, spinous projects posterior, remaining four will join with other vertebrae (2 superior, 2 inferior)

Cervical VertebraeC1-C7

C1=AtlasNo body or spinous processSupports head

C2=AxisAllows head to rotate from side to side

Thoracic VertebraeT1-T12

Larger body

No transverse foramen

Lumbar VertebraeL1-L5

Sacrum and CoccyxCoccyx

Sacrum4-5 separate vertebrae in a child, fuse into one as an adultTail bone

Five separate vertebrae until age 25, when they fuse into a wedge shaped bone

Curvature of Vertebral ColumnIncreases carrying strength

Makes balance possible

SternumBreast boneDagger shaped3 partsManubriumBodyXiphoid process

RibsTrue RibsUpper 7Directly attached to sternum by costal cartilage

False RibsDo not attach to sternumUpper 3 attach to last true ribBottom 2 do not attach to anythingCalled floating ribs

Skeletal SystemAppendicular SkeletonAppendicular SkeletonConsists of upper and lower extremities

Upper ExtremitiesBones of shoulder girdle

Upper arm

Lower arm

Carpals

Metacarpals

PhalangesBones of the shoulder girdleClavicleOnly articulation With skeleton is formed by sternoclavicular joint (clavicle and sternum)

ScapulaDoesnt form a joint with axial skeletonAcromion processGlenoid cavity

Upper and Lower ArmUpper ArmLower ArmHumerusCapitulumTrochleaRadiusThumb side

UlnaPinky sideDoesnt articulate with any carpal bonesOlecranonCarpals8 carpal bones

2 rows of 4 bones:

Proximal Row from pinky towards thumb:Pisiform, triquetrum, lunate, scaphoidDistal Row from pinky towards thumb:Hamate, capitate, trapezoid, trapezium

Metacarpals and PhalangesMetacarpalsPhalangesNumbered I-V (1=thumb)3 in each finger, 2 in thumbProximal, middle, distal (no middle in thumb)

Lower ExtremitiesPelvic girdle

Upper Leg

Lower leg

Tarsals

Metatarsals

PhalangesBones of pelvic girdleCoxal Bone (3 parts)IliumIschiumPubisAcetabulumCan be divided into two parts by imaginary line called pelvic inletAbove pelvic inlet is called false pelvisBelow pelvic inlet is called true pelvisPubis symphis

Upper and Lower LegFemurTibia and FibiaLongest and heaviest bone in body

Patella-kneecapTibia- larger, medial lower leg boneArticulates with femur to form knee jointShin bone

Fibula- smallerTarsalsCalcaneus-heel bone

Talus-uppermost tarsal

Navicular, Cuneiforms, cuboid

Metatarsals and PhalangesMetatarsalsPhalangesNumbered I-V starting with big toeMinature long bones of toe, two in great toe, three in other toes Distal, Medial, ProximalBone BreaksAnd DisordersGreenstick Fracture

Transverse

Communited

Simple

Compound

Stress

Spiral

Bone Diseases- Osteoporosis

Osteomalacia

Rickets

Pagets Disease

Osteomyelitis

Lordosis, Kyphosis, Scoliosis

Fibrous Dysplasia

Osteogenesis Imperfecta

Skeletal SystemArticulationsFunctions and ClassificationsFunctions:Holds bones togetherGives skeleton mobility

Classifications:Functionally- amount of movement that is allowedStructurally- what its made ofFunctional ClassificationSynarthroses- immovable joints

Amphiarthroses- slightly moveable joints

Diarthroses- freely moveable jointsStructural ClassificationFibrous

Cartilaginous

SynovialFibrousBones are united by fibrous connective tissue

Example: Sutures of the skullCartilaginous JointsBones ends are connected by cartilage

Examples: Amphiarthrotic- pubis symphyis and interveterbal joints

Examples: Synarthrotic- epiphyseal plates of long bone and the joints between the true ribs and sternumSynovial JointsArticulating ends of bones are separated by a joint cavity that contains synovial fluidAll have four features:Articular cartilageFibrous articular capsuleJoint cavityReinforcing ligaments

Types of Synovial JointsPlane JointEx: carpalsHinge JointEx: ElbowPivot JointEx: Radioulnar jointCondyloid JointEx: MetacarpalsSaddle JointEx: ThumbBall and Socket JointEx: Shoulder and hip

Inflammatory DisordersBursitisSprainsArthritisOsteoarthritisRheumatoid arthritisGouty arthritis/gout