SKULL

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pearl

Cards (41)

  • Bones of the Skull: 22
  • Cranium & Calva: 8 bones
    Paired: parietal & temporal
    Unpaired: frontal, ethmoid, sphenoid & occipital
  • Facial: 14 bones
    Paired: zygomatic, maxilla, nasal, lacrimal, palatine & inferior conchae
    Unpaired: vomer & mandible
  • Contents: brain and special senses cranial cavity not completely closed
    = CSF → foramen magnum
    = brainstem
  • Cranium: without mandible
  • CALVARIA = bone enclosing the brain
  • CALVA = skull cap where one can see the inside base of the skull /floor of the calvaria with fossae
  • FACIAL SKELETON = below calvaria plus the mandible
  • Exterior of skull:
    1. Norma verticalis = top view
    2. 3 sutures: coronal, sagittal, lambdoid for the growth and development of the brain
  • Exterior of skull:
    anterior and posterior:
    fontanelles / bregma and lambda
  • Exterior of skull:
    • parietal tuber/eminence
    • parietal foramen: emissary veins from superior sagittal sinus
  • EXTERIOR OF SKULL
    Norma frontalis = frontal bone and face
    = glabella: between superciliary arches
    = nasion
    = orbits and nasal apparatus
  • Exterior of skull:
    3. Norma occipitalis = back
    = lambdoid suture to occipitomastoid and parietomastoid sutures
    = occipital bone
    = external occipital protuberance (inion)
  • Exterior of skull:
    3. Norma occipitalis = back
    = superior nuchal line (between scalp and neck)
    ligamentum nuchae, trapezius, sternocleidomastoid,
    splenius capitis
    = superior nuchal line
    • galea aponeurotica & occipitofrontalis
  • Exterior of skull: Norma lateralis
    4. Norma lateralis – temporal line superiorly from zygomatic process of frontal, coronal and parietal bone
  • Exterior of skull: Norma lateralis
    = temporal fossa: temporalis,deep temporal A&N,superfial temporal A.
  • Exterior of skull: Norma lateralis
    =pterion : antero-inferior corner of the parietal bone articulates with the greater wing of sphenoid marks the anterior branch of middle meningeal artery
  • C. Exterior of skull:

    Norma lateralis= frontal, sphenoid, parietal and squamous part of temporal
  • Exterior of skull:
    4. Norma lateralis –
    zygomatic arch: temporal process of zygomatic bone + zygomatic process of temporal bone
    • easily palpable
  • Exterior of skull:
    4. Norma lateralis
    external acoustic meatus: below posterior root of zygoma
    above: supramastoid crest
    ant.: postero superior margin of orifice
    post.: vertical line
    → lateral wall of mastoid / tympanic antrum (petrous part
    of temporal bone)
  • Exterior of skull:
    4. Norma lateralis
    mastoid part of temporal bone mastoid processes
    mastoid foramen – emissary vein from sigmoid sinus
    • asterion: parieto occipitomastoid
    sutures + lamboid suture
  • Exterior of skull:
    4. Norma lateralis
    Styloid process: in front of mastoid process covered by parotid gland
    → stylohoid, styloglossus, stylopharyngeus m.
    • behind its base: facial nerve
  • Exterior of skull:
    4. Norma lateralis. Infratemporal fossa: behind maxilla
    • temporalis, maxillary artery, pterygoid plexus of veins,
    • deepest part: media; pterygoid, mandibular nerve and chorda tympani
    • upper part: maxillary nerve
  • C. Exterior of skull:
    5. Norma basalis: Basal view
    • from incisors (maxillae) to sup. nuchal line laterally: other teeth, zygomatic and mastoid process
  • C. Exterior of skull:
    5. Norma basalis: Basal view
    ▪ Anterior part: hard palate and
    alveolar arches
    = alveolar arch – 16 sockets / alveoli for the teeth
    = lateral incisive foramina: terminal branches of
    greater palatine vessels and nasopalatine nerve
    = lesser pal. foramina: lesser pal. nerves and vessels
  • C. Exterior of skull:
    5. Norma basalis
    Middle part: posterior border of bony palate to transverse bone along anterior of foramen magnum
    posterior of vomer: bet. posterior nasal apertures & in
    front of inferior sphenoid & base of occipital bone
  • C. Exterior of skull:
    5. Norma basalis
    • pharyngeal tubercle; attachment of fibers of sup. constrictor of pharynx
    • foramen ovale: mandibular division of CN VII
  • C. Exterior of skull:
    5. Norma basalis:
    • foramen spinosum: middle
    meningeal artery to middle
    cranial fossa
  • C. Exterior of skull:
    5. Norma basalis:
    • foramen lacerum: between greater wing of sphenoid and occipital bone; no large structure but emissary vein from cavernous sinus and meningeal arterial branches
  • C. Exterior of skull:
    5. Norma basalis:
    • carotid canal: internal carotid artery
  • Posterior Part:
    = foramen magnum: medulla oblongata
    = hypoglossal (ant. condylar) canal: hypoglossal nerve
    = jugular foramen:
    anterior – inferior petrosal sinus;
    intermediate – CN IX, X, XII;
    posterior -internal jugular vein
    = Stylomastoid foramen: CN VII
  • Interior of Cranium: 3
    1. Anterior Fossa
    = anteriorly & laterally: frontal bone
    = floor: orbital parts of frontal, cribriform plate of ethmoid lesser wings and anterior parts of body of sphenoid
  • Interior of Cranium: 3
    1. Anterior Fossa
    = minute olfactory nerve (cribriform plate)
    = ant. ethmoidal canal → nerves and vessels
    = post. ethmoidal canal → vessels
  • Interior of Cranium: 3
    2. Middle Fossa
    Ant.: posterior borders of lesser wings of sphenoid, anterior clinoid process & anterior margin of sulcus chiasmatis
    Post.: petrous parts of temporal bones and dorsum sellae of sphenoid
    Lat.: temporal squamae, parietal bones and greater wings of sphenoid
    Floor: body of sphenoid
  • Interior of Cranium: 3
    2. Middle Fossa
    optic canal: optic nerve, ophthalmic artery, meninges
    =superior orbital fissure: terminal br. of ophthalmic nerve, ophthalmic veins, CN III, IV, VI
    =foramen rotundum: maxillary nerve
    =foramen ovale: mandibular nerve (CN V)
    =foramen spinosum: middle men. artery
    =foramen lacerum: posteriorly – internal carotid artery
  • 3. Posterior Fossa:
    = largest and deepest
    = cerebellum, pons & medulla obl.
    = foramen magnum
    = jugular foramen
    = hypoglossal canal
    = internal acoustic meatus
    • facial canal
    = facial nerve
  • SKULL and CHANGES:
    At Birth:
    = relatively large but facial par small
    • brain vs. mandible and maxillae
    = no diploe
    = incomplete ossification of bone
  • Fontanelles:
    Anterior = largest; diamond- shaped, 4.0 cm AP diameter,
    2.5 cm transverse diam. closes at 18 mos. old → bregma
    2. Posterior – triangular
    • closes at 2-3 months old → lambda
  • Fontanelles:
    3. Sphenoid / Anterolateral
    = at sphenoidal angle of parietal bones
    = closes at 2-3 months old → pterion
    4. Mastoid / Posterolateral
    = at mastoid angle of parietal bone
    = closes at end of 1st year → asterion
  • Other Features:
    Diploe – appears about 4 y/o
    Mastoid process – bulges at 2 y/o, air cells at 6 y/o