skeleton axialcrestwood primary school：骨架的轴向查看小学

1、06 Skeleton: AxialHuman BiologyClassification of BonesHuman body consists in 206 bones. They are divided in two groups:Axial skeleton (form the long axis of the body) includes bones of the skull, vertebral column, and rib cage. Functions: protecting, supporting or carry other body parts.Appendicular

2、 skeleton bones of the upper and lower limbs, shoulder, and hip. Function: locomotion and manipulation of our environmentGross Anatomy of Bones: Bone TexturesEvery bone has two textures:Compact bone (also called cancellous bone) dense outer layerSpongy bone - (internal) honeycomb of trabeculae fille

3、d with red or yellow bone marrowClassification of Bones: By ShapeLong bones longer than they are wide (e.g., humerus)Has a shaft plus two endsFigure 6.2aBones come in many sizes and shapes. For most part , bones are classified by their shape as: long, short, flat and irregularEx: All limb bones exce

4、pt patella and wrist and ankle bones are long boneStructure of Long BoneFigure 6.3Structure of Long BoneLong bones consist of a diaphysis and an epiphysis and membranes.DiaphysisTubular shaft that forms the axis of long bonesComposed of compact bone that surrounds the medullary cavityYellow bone mar

5、row (fat) is contained in the medullary cavityStructure of Long BoneEpiphysesExpanded ends of long bonesExterior is compact bone, and the interior is spongy boneJoint surface is covered with articular (hyaline) cartilageEpiphyseal line (remnant of the epiphyseal plate) separates the diaphysis from t

6、he epiphysesClassification of Bones: By ShapeFigure 6.2bShort bonesCube-shaped bones of the wrist and ankleSesamoid bones “shaped like a sesame seed” that form within tendons (e.g., patella). They vary in size and number in different individual. Some sesamoid bones act to alter the direction of pull

7、 of a tendonClassification of Bones: By ShapeFlat bones thin, flattened, and a bit curved (e.g., sternum, and most skull bones)Figure 6.2cStructure of a Flat BoneFigure 6.4Classification of Bones: By ShapeIrregular bones bones with complicated shapes (e.g., vertebrae and hip bones)Figure 6.2dFunctio

8、n of BonesSupport form the framework that supports the body and cradles soft organs. Ex: Lower limbProtection provide a protective case for: the brain (bones of skull), spinal cord (vertebrae), and vital organs (rib cage)Movement provide levers for musclesMineral storage bone is a reservoir for mine

9、rals, especially calcium and phosphorusBlood cell formation hematopoiesis occurs within the marrow cavities of bonesTuberosity rounded projectionCrest narrow, prominent ridge of boneTrochanter large, blunt, irregular surfaceLine narrow ridge of boneBone Markings: Projections Sites of Muscle and Liga

10、ment AttachmentTubercle small rounded projectionEpicondyle raised area above a condyleSpine sharp, slender projectionProcess any bony prominenceBone Markings: Projections Sites of Muscle and Ligament AttachmentChemical Composition of Bone: OrganicBone has both organic and inorganic components. Organ

11、ic components:1.-Cells:Osteoblasts bone-forming cellsOsteocytes mature bone cellsOsteoclasts large cells that resorb or break down bone matrix2.- Osteoid unmineralized bone matrix composed of proteoglycans, glycoproteins, and collagenChemical Composition of Bone: InorganicThe balance of the bone tis

12、sue (65% by mass) consists of inorganic mineral salts:Hydroxyapatites, or mineral saltsMainly calcium phosphatesResponsible for bone hardness and its resistance to compressionThe SkeletonThe skeleton (“dried up body” or mummy)It is strong, yet light, and almost perfectly adapted for the protective,

13、locomotor and manipulative functions it performComposed of bones, cartilages, joints and ligaments, accounts for about 20% of body mass.The skeleton is divided into Axial and AppendicularThe Axial SkeletonThis part of skeleton supports the head, neck and trunk and it protects the brain, spinal cord

14、and the organs in the thoraxEighty bones segregated into three regions1.- Skull2.- Vertebral column3.- Bony thoraxThe SkullThe skull, the bodys most complex bony structure, is formed by the cranium and facial bones Cranium protects the brain and is the site of attachment for head and neck musclesFac

15、ial bonesSupply the framework of the face, the sense organs, and the teethProvide openings for the passage of air and foodAnchor the facial muscles of expressionAnatomy of the CraniumThe cranium can be divided in : 1.- cranial vault (calvaria) 2.- cranial base (floor)Eight cranial bones two parietal

16、, two temporal, frontal, occipital, sphenoid, and ethmoidCranial bones are thin and remarkably strong for their weightFrontal BoneForms the anterior portion of the craniumArticulates posteriorly with the parietal bones via the coronal sutureThe most anterior part of the frontal bone is the vertical

17、frontal squama, commonly called the foreheadMajor markings include the supraorbital margins, the anterior cranial fossa, and the frontal sinuses (internal and lateral to the glabella)Skull: Anterior ViewFigure 7.2aSkull: Posterior ViewFigure 7.2bParietal Bones and Major Associated SuturesThey are cu

18、rved, rectangular bones. Form most of the superior and lateral aspects of the skullFigure 7.3aOccipital Bone and Its Major MarkingsIt articulates anteriorly with the paired parietal and temporal bones via the lambdoid and occipitomastoid sutures.It also joins with the sphenoid bone in the cranial fl

19、oor via a plate called the pharingeal tubercule.Forms most of skulls posterior wall and baseMajor markings include the posterior cranial fossa, foramen magnum, occipital condyles, and the hypoglossal canalFigure 7.2bTemporal BonesFigure 7.5 Between the styloid and mastoid processes exist the styloma

20、stoid foramen that allow cranial nerve VII to leave the skull. The mastoid region of the temporal bone exhibits the conspicuous mastoid process, an anchoring site for some neck musclesSphenoid BoneFigure 7.6a, bEthmoid BoneFigure 7.7Allow the olfatory nerves to pass from the smell receptors in the n

21、asal cavites to the brainMandible and Its MarkingsFigure 7.8aMaxillary BoneFigure 7.8bThe anterior nasal spine allows the infraorbital nerve and artery to reach the face Vertebral Column & RibsVertebral ColumnFormed from 26 irregular bones (vertebrae) connected in such a way that a flexible curved s

22、tructure resultsCervical vertebrae 7 bones of the neckThoracic vertebrae 12 bones of the torsoLumbar vertebrae 5 bones of the lower backSacrum bone inferior to the lumbar vertebrae that articulates with the hip bonesVertebral ColumnFigure 7.13Vertebral Column: CurvaturesPosteriorly concave curvature

23、s cervical and lumbarPosteriorly convex curvatures thoracic and sacralAbnormal spine curvatures include scoliosis (abnormal lateral curve), kyphosis (hunchback), and lordosis (swayback)Vertebral Column: LigamentsAnterior and posterior longitudinal ligaments continuous bands down the front and back o

24、f the spine from the neck to the sacrumShort ligaments connect adjoining vertebrae togetherVertebral Column: LigamentsFigure 7.14aVertebral Column: Intervertebral DiscsCushionlike pad composed of two partsNucleus pulposus inner gelatinous nucleus that gives the disc its elasticity and compressibilit

25、yAnnulus fibrosus surrounds the nucleus pulposus with a collar composed of collagen and fibrocartilageVertebral Column: Intervertebral DiscsFigure 7.14bGeneral Structure of VertebraeBody or centrum disc-shaped, weight-bearing regionVertebral arch composed of pedicles and laminae that, along with the

26、 centrum, enclose the vertebral foramenVertebral foramina make up the vertebral canal through which the spinal cord passesGeneral Structure of VertebraeSpinous processes project posteriorly, and transverse processes project laterallySuperior and inferior articular processes protrude superiorly and i

27、nferiorly from the pedicle-lamina junctionsIntervertebral foramina lateral openings formed from notched areas on the superior and inferior borders of adjacent pediclesGeneral Structure of VertebraeFigure 7.15Cervical VertebraeSeven vertebrae (C1-C7) are the smallest, lightest vertebraeC3-C7 are dist

28、inguished with an oval body, short spinous processes, and large, triangular vertebral foraminaEach transverse process contains a transverse foramenCervical VertebraeTable 7.2Cervical Vertebrae: The Atlas (C1)The atlas has no body and no spinous processIt consists of anterior and posterior arches, an

29、d two lateral massesThe superior surfaces of lateral masses articulate with the occipital condylesCervical Vertebrae: The Atlas (C1)Figure 7.16a, bCervical Vertebrae: The Axis (C2)The axis has a body, spine, and vertebral arches as do other cervical vertebraeUnique to the axis is the dens, or odonto

30、id process, which projects superiorly from the body and is cradled in the anterior arch of the atlasThe dens is a pivot for the rotation of the atlas Cervical Vertebrae: The Axis (C2)Figure 7.16cCervical Vertebrae: The Atlas (C2)Figure 7.17aThoracic VertebraeThere are twelve vertebrae (T1-T12) all o

31、f which articulate with ribsMajor markings include two facets and two demifacets on the heart-shaped body, the circular vertebral foramen, transverse processes, and a long spinous processThe location of the articulate facets prevents flexion and extension, but allows rotation of this area of the spi

32、neThoracic VertebraeFigure 7.17bLumbar VertebraeThe five lumbar vertebrae (L1-L5) are located in the small of the back and have an enhanced weight-bearing functionThey have short, thick pedicles and laminae, flat hatchet-shaped spinous processes, and a triangular-shaped vertebral foramenOrientation

33、of articular facets locks the lumbar vertebrae together to provide stabilityLumbar VertebraeFigure 7.17cSacrumSacrumConsists of five fused vertebrae (S1-S5), which shape the posterior wall of the pelvisIt articulates with L5 superiorly, and with the auricular surfaces of the hip bones Major markings

34、 include the sacral promontory, transverse lines, alae, dorsal sacral foramina, sacral canal, and sacral hiatusCoccyxCoccyx (Tailbone)The coccyx is made up of four (in some cases three to five) fused vertebrae that articulate superiorly with the sacrumSacrum and Coccyx: Anterior ViewFigure 7.18aChar

35、acteristics of Cervical,Thoracic and Lumbar Vertebrae CharacteristicsCervical (3-7)ThoracicLumbarBodySmall, wide side to sideLarger than cervical, heart shaped, bears two costal demifacetsMassive, kidney shapedSpinous processShort bifid, projects directly posteriorlyLong, sharp, projects inferiorlyS

36、hort, blunt, projects directly posteriorlyVertebral foramenTriangularCircularTriangularTransverse processContain foraminaBear facets for ribs (except T11-T12)Thin and taperedSup. and inf. art. processSup facet sup-posInf facet inf-antSup facets posteriorInf. facets anteriorSup facet posmedInf. facet

37、 ant-latMovementsFlex and extension, lateral flex, rotationRotation, limited lateral flex (ribs), flex & ext preventedFlex and ext, some lat flexion, rotation preventedHomeostatic ImbalanceHerniated (prolapsed) disc. Severe or sudden physical trauma to the spine, may result in hernation of one or mo

38、re discs. A herniated disc (slipped disc) usually involves rupture of the annulus fibrosus followed by protrusion of the spongy nucleus pulposus through the annulus (Fig 7.14). If the protrusion presses on the spinal cord or on spinal nerves exiting from the cord, numbness or excruciating pay result.Treatments: moderated exercise, massage, heat ther. and painkillers if this fail surgeryBony Thorax (Thoraci