Axial skeleton

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Transcript of Axial skeleton

  • The SkeletonConsists of bones, cartilage, joints, and ligamentsComposed of 206 named bones grouped into two divisions

    Axial skeleton (80 bones)Appendicular skeleton (126 bones)

  • The Axial SkeletonFormed from 80 named bones

    Consists of skull, vertebral column, and bony thorax

  • Bone MarkingsProjections that provide attachment for muscles and ligaments

    Projections that help form joints

    Depressions and openings for passage of nerves and blood vessels

  • The SkullFormed by cranial and facial bones

  • Overview of Skull GeographyThe skull contains smaller cavitiesMiddle and inner ear cavities in lateral aspect of cranial baseNasal cavity lies in and posterior to the noseOrbits house the eyeballsAir-filled sinuses occur in several bones around the nasal cavity

  • Overview of Skull GeographyThe skull contains approximately 85 named openingsForamina, canals, and fissuresProvide openings for important structuresSpinal cordBlood vessels serving the brain12 pairs of cranial nerves

  • Cranial BonesFormed from eight large bonesPaired bones includeTemporal bonesParietal bones

    Unpaired bones includeFrontal boneOccipital boneSphenoid boneEthmoid bone

  • Sutural Bones Small bones that occur within suturesIrregular in shape, size, and locationNot all people have sutural bones

  • The Skull Posterior View

  • Inferior Aspect of the Skull

  • Lateral Aspect of the Skull

  • The Temporal Bone

  • The Sphenoid Bone

  • The Ethmoid Bone Lies between nasal and sphenoid bonesForms most of the medial bony region between the nasal cavity and orbits

  • Mandible

  • Maxillary Bones Articulate with all other facial bones except the mandibleContain maxillary sinuses largest paranasal sinusesForms part of the inferior orbital fissure

  • Maxillary Bones

  • Bones of the Face

  • Special Parts of the Skull OrbitsNasal cavityParanasal sinusesHyoid bone

  • Nasal Cavity

  • Nasal Septum

  • Orbits

  • Paranasal Sinuses Air-filled sinuses are located within Frontal boneEthmoid boneSphenoid boneMaxillary bones Lined with mucous membraneServe to lighten the skull

  • Paranasal Sinuses

  • The Hyoid Bone Lies inferior to the mandibleThe only bone with no direct articulation with any other boneActs as a movable base for the tongue

  • Lab time

  • The Vertebral Column Formed from 26 bones in the adultTransmits weight of trunk to the lower limbsSurrounds and protects the spinal cordServes as attachment sites for muscles of the neck and backHeld in place by ligamentsAnterior and posterior longitudinal ligaments Ligamentum flavum

  • The Vertebral Column

  • Ligaments and Intervertebral Discs

  • Ligaments and Intervertebral Discs

  • Regions and Normal Curvatures

  • General Structure of Vertebrae

  • Cervical Vertebrae Seven cervical vertebrae (C1 C7) smallest and lightest vertebraeC3 C7 are typical cervical vertebrae Body is wider laterallySpinous processes are short and bifid (except C7)Vertebral foramen are large and triangularTransverse processes contain transverse foraminaSuperior articular facets face superoposteriorly

  • Cervical Vertebrae

  • Cervical Vertebrae

  • The Atlas

  • The Atlas

  • The Axis

  • Thoracic Vertebrae

  • Lumbar Vertebrae

  • Lumbar Vertebrae

  • Sacrum

  • Bony ThoraxForms the framework of the chestComponents of the bony thoraxThoracic vertebrae posteriorlyRibs laterally Sternum and costal cartilage anteriorlyProtects thoracic organsSupports shoulder girdle and upper limbsProvides attachment sites for muscles

  • The Bony Thorax

  • The Bony Thorax

  • RibsAll ribs attach to vertebral column posteriorlyTrue ribs - superior seven pairs of ribsAttach to sternum by costal cartilageFalse ribs inferior five pairs of ribsRibs 11-12 are known as floating ribs

  • Ribs

  • Ribs

  • The Axial Skeleton Throughout LifeMany bones of the face and skull form by intramembranous ossificationEndochondral bones of the skullOccipital bone, sphenoid and ethmoid bones, and parts of the temporal bone

  • The Axial Skeleton Throughout LifeMembrane bones begin to ossify in second month of developmentBone tissue grows outward from ossification centersFontanels unossified remnants of membranes

  • Fontanels

  • The Axial Skeleton Throughout LifeAging of the axial skeleton

    Water content of the intervertebral discs decreases

    By age 55, loss of a few centimeters in height is common

    Thorax becomes more rigid

    Bones lose mass with age

  • Disorders of the Axial SkeletonAbnormal spinal curvatures

    Scoliosis an abnormal lateral curvature

  • Disorders of the Axial SkeletonAbnormal spinal curvatures

    Kyphosis an exaggerated thoracic curvature

  • Disorders of the Axial SkeletonAbnormal spinal curvatures

    Lordosis an accentuated lumbar curvature "swayback"