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<p>Skeletal System axial Skeleton chapter 7 </p> <p>Skeletal Systemaxial Skeletonchapter 7</p> <p>Honors BiologySkeletal SystemComposed of:BonesCartilageJointsLigaments ~ 20% of body massDivided into axial &amp; appendicular </p> <p>Axial Skeleton80 bones in 3 regions:SkullVertebral columnThoracic cage</p> <p>Functions of the Axial SkeletonSupports head, neck, and trunkProtects brain, spinal cord, and organs of the thoracic cavityThe SkullFormed by:Cranium Enclose &amp; protect brainAttachment sites for head &amp; neck musclesFacial bonesForm framework of faceContain cavities for special sense organsProvide openings for air &amp; food passageSecure the teethAnchor muscles of facial expression</p> <p>Sutures Interlocking joints between flat bones (cranium)</p> <p>Newborn Skullfontanels: soft spots present between cranial bones made of unossified mesenchymeeventually replaced by mature bonefunction: provide some flexibility to fetal head allowing skull to change shape as it passes thru birth canal</p> <p>Newborn Skull</p> <p>Newborn Skull</p> <p>Cranium 8 bones :2 paired: parietal, temporal4 single: frontal, occipital, ethmoid, sphenoid</p> <p>Frontal BoneForms anterior craniumArticulates posteriorly with parietal bonesParts:SquamousForms foreheadSupraorbital marginsForms: superior wall of orbits Anterior cranial fossa: houses frontal lobes of brain</p> <p>Parietal Bonesmost of superior and lateral aspects of the skull forming the bulk of the cranial vault4sutures:Coronal sutureParietal bones meet frontalSagittal sutureRt parietal bone meets lt parietal boneLambdoid sutureParietal bones meet occipital boneSquamous sutureParietal bones meet temporal bones</p> <p>Occipital BoneForms most of skulls posterior wall &amp; base@ base is foramen magnumlarge hole brain stem, spinal cordoccipital condylesarticulate with 1st vertebra</p> <p>Temporal Bonesform inferolateral aspects of the skull3 major parts:Squamous TympanicPetrous Squamous portion : Temporal Bonesabuts squamous sutureZygomatic processMeets zygomatic bone anteriorly forming zygomatic archMandibular fossareceives condylar process of mandible forming the temporomandibular joint (TMJ)</p> <p>Tympanic part: Temporal Bonesurrounds external acoustic meatus : external ear canal receives sound waves &amp; directs them inward to ear drum</p> <p>Petrous Portion: Temporal Bonehouses middle &amp; inner earSense organs for hearing &amp; equilibriumforms part of base of skullMastoid Processlump just posterior to earAttachment site for neck muscles Styloid ProcessNeedle-like attachment for tongue &amp; neck musclesTemporal Bones</p> <p>Sphenoid Bonebat-shaped spans width of middle cranial fossaArticulates with every other cranial boneContains sphenoid sinusesSuperior surface: sella turcica a saddle-shaped fossa where the pituitary gland sitsaka hypophyseal fossaSphenoid Bone</p> <p>Ethmoid Bonelike a sievemidline of anterior part of cranial floor, anterior to sphenoid, posterior to nasal bonescribiforme plate: forms roof of nasal cavity, the holes of the sieve where olfactory nerves pass from roof of nasal cavity to braincrista galla: triangular process which serves as pt of attachment for meninges of brainEthmoid Bone</p> <p>Ethmoid Boneperpendicular plate: forms superior portion of nasal cavitysuperior &amp; middle nasal conchae: (or turbinate) increase vascular &amp; mucous membrane surface area in nasal cavities: aids in sense of smell, warms, filters &amp; moistens air being inhaled. Filters because the turbinates cause air to swirl as a result inhaled particles strike &amp; become trapped in mucus</p> <p>Ethmoid Bone</p> <p>Sometimes when you study anatomy, you start seeing others differently.</p> <p>Facial Bonesshape of face changes dramatically during 1st 2 yrs of life: brain &amp; cranial bones expand1st set of teeth eruptparanasal sinuses enlargegrowth of face stops ~16 years oldFacial Bones14 facial bones:2 nasal bones2 maxillae2 zygomatic bones1 mandible2 lacrimal bones2 palatine bones 2 inferior nasal conchae1 vomerMandible largest &amp; strongest facial bone (lower jaw)alveolar processes hold lower teeth socketsmental foramen: dentist numb mental nerve</p> <p>Maxillae= upper jaws*articulate with every bone in face except the mandibleform part of floor of orbits, parts of nasal cavity, &amp; most of the hard palate (bony roof of mouth)each one has large maxillary sinusalveolar process is small arch that contains the alveolar sockets for upper set of teethMaxillae </p> <p>Cleft Palate &amp; Cleft Lip10-12 wks gestation the palatine processes of maxillae typically joinnot doing so cleft palate +/- cleft lipspeech &amp; swallowing can be affectedmany ear infectionsreparative surgery recommended 1st few wks of life / surgery needs to be completed by 12 18 mos b/4 speech: speech therapy &amp; orthodontic care frequently necessary</p> <p>Zygomatic Bonescheekbones: the temporal process of the zygomatic bone articulates with the zygomatic process of the temporal bonealso part of floor of orbit</p> <p>Nasal Bonesform part of the bridge of the nose (rest is cartilage)</p> <p>Lacrimal Bonesthin, about the size of pinky fingernail (smallest bones of face)part of medial wall of each orbiteach contain lacrimal fossa that houses lacrimal sac: gathers tears nasal cavity</p> <p>Palatine BonesL-shaped pair of bones that form the posterior portion of the hard palate &amp; part of floors of nasal cavity &amp; orbit</p> <p>Vomer shaped bone on the floor of nasal cavity forming inferior portion of nasal septum</p> <p>Inferior Nasal Conchaeinferior to the middle nasal conchae of the ethmoid bone forming part of lateral wall of nasal cavitysame function as superior &amp; middle conchae: swirling inhaled air to deposit particulates but not involved in sense of smell</p> <p>Paranasal SinusesIn these 4 bones + sphenoidMucosa-lined, air-filled with small openings that connect to nasal cavityMucosa helps warm &amp; humidfy inhaled airadd resonance to voice</p> <p>Hyoid Bone U-shaped *does not articulate with any other bone in skeletonsuspended by ligaments from styloid process of temporal bonein anterior neck between mandible &amp; larynxFunction: supports tongue*frequently fractured during strangulationHyoid Bone</p> <p>Vertebral Columnaka spine, backbone2/5 of persons height26 in adult (starts as 33, some fuse to form sacrum &amp; coccyx)7 cervical12 thoracic5 lumbar1 sacrum1 coccyx </p> <p>Vertebral Column</p> <p>Fetus has anteriorly concave curve3 mos old when holds head cervical curve developslumbar curve develops as infant sits up, stands, walksIntervertebral Discsbetween bodies of consecutive vertebraunder compression they flatten &amp; broadenharden, less elastic w/aging &amp; narrow loss of heightannulus fibrosus: outer fibrous ringnucleus pulposus: inner soft, highly elasticIntervertebral Discs</p> <p>Parts of a VertebraBodythicker, anterior portion, weight bearing portionVertebral Foraminacontains spinal cord, adipose, areolar CT, blood vesselsSpinous Process1 of 7 processes, posterior, palpable on back of bodyTransverse Processes: on each side, extending laterally</p> <p>Vertebrae: 1st &amp; 2nd Cervical Atlasring-shapedarticulates with condyles of occipital boneallows you to nod head yesAxis 2nd cervical v.allows you to shake head no</p> <p>Typical Cervical VertebraeC-3 to C7smaller than other v. except coccyx but vertebral foramen largestall cervical v. have extra foramen: 2 transverse foramen for vertebral a., v., &amp; n.</p> <p>Typical Thoracic VertebraeT-1 to T-12larger &amp; stronger than cervical v.distinguishing feature: articulate with ribs (facets on transverse processes of T-1 to T-10</p> <p>Typical Lumbar VertebraeL-1 to L-5largest &amp; strongest of the vertebraeprocesses are short &amp; thick</p> <p>Sacrum triangular bone formed by union of S-1 to S-5fusion begins ~16, complete by age 30female: shorter, wider, more curved S-2 to S-3</p> <p>Coccyxsmall triangleformed by fusion of 4 coccygeal v. (Co-1 to Co-4), start between 20 &amp; 30females points inferiorly; males it points anteriorly</p> <p>Thoraxrefers to entire chestskeletal part of thorax is thoracic cageSternumRibs </p> <p>Sternumaka breastboneflat bone in center of anterior thorax3 bones that fuse by age 25</p> <p>SternumManubriumsuperior portionsuprasternal notchclavicular notchesarticulates with costal cartilage of 1st &amp; 2nd ribsternal angle: where it articulates with body</p> <p>Sternum2. Bodymiddle &amp; largest portionarticulates with costal cartilage of 2nd thru 10 ribs</p> <p>Sternum 3. Xiphoid Processcartilagenous in infancy not completely ossified until ~age 40avoid it during CPR</p> <p>Ribs12 pairs increase in length 1st thru 7th then decrease in length to 12th 1st thru 7th ribs (true ribs) have direct anterior attachment to sternum by strip of hyaline cartilage which contribute to elasticity of thoracic cage 8th thru 10th ribs attach to each other &amp; then to cartilages of 7th rib11th &amp; 12th ribs: floating ribsRibs</p> <p>Ribsall 12 attach posteriorly to vertebraeParts of a RibHeadNeckTubercle Body Costal Angle</p> <p>Abnormal Curvatures of SpineScoliosis lateral bendingusually in thoracic region</p> <p>Abnormal Curvature of SpineKyphosis exaggeration of the thoracic curveseen in TB of spine, congenital malformation, elderly</p>