Skull And Skull Devolpment Flashcards

1
Q

Viscerocranium vs neurocranium

A

Viscero: bones of the facial skeleton
- develops from neural crest cells in the first 2 pharyngeal arches

Neuro: bones that directly surround the brain and comprised of inner and outer tables
- develops from the paraxial mesoderm

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2
Q

Bones that are part of both viscerocranium and neurocranium

A

Sphenoid, temporal, ethmoid bones

  • parts of each arise from each subtype and then fuse together into one single bone
  • ethmoid bone is almost completely viscerocranium except for the cribiform plate
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3
Q

How many bones are in the cranium?

A

28 bones (27 + mandible)

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4
Q

Viscerocranium bones include what?

A

Ethmoid and inferior nasal concha

Lacrimal

Pterygoid process of sphenoid bone

Tympanic and styloid part of temporal bone

Vomer

Maxilla

Nasal

Palatine

Zygomatic

Mandible

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5
Q

Neurocranium bones include what?

A

Cribiform plate of ethmoid
- site of CN1

Frontal

Occipital

Sphenoid (minus the pterygoid process)

Temporal (minus the tympanic)

Parietals

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6
Q

Diploe

A

Middle portion of the cranium bones that surround the brain. Contains lots of red bone marrow

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7
Q

Hard palate includes what bones?

A

Maxilla and palatine bones

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8
Q

Soft palate includes what bones?

A

Sphenoid, vomer

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9
Q

What bones create your nasal septum?

A

Vomer and perpendicular plate of the ethmoid bone

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10
Q

What is the purpose of Nasal concha bones

A

To induce turbulence for breathing

Allows for warming of air before it hits the lungs

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11
Q

What are the paranasal sinuses and the bones they are in?

A

Frontal sinus

Ethmoid air cells/sinus

Sphenoid sinus

Maxillary sinus

  • also nasolacrimal duct, but this not associated with a bone*
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12
Q

What are the purposes of sinuses?

A

To alleviate pressure and compensate for barometric pressure

these openings are key areas of infections

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13
Q

What are fossa in the skull and the bones that create the respective fossa?

A

Anterior cranial fossa:

  • frontal bone
  • cribriform plate of ethmoid
  • lesser wing of the sphenoid bone

Middle cranial fossa:

  • greater wing and sella turcica of the sphenoid bone
  • squamous and petrous parts of the temporal bone

Posterior cranial fossa:

  • petrous and mastoid of the temporal bone
  • occipital bone

Posterior and middle fossa is separated via the petrous ridge

Middle and anterior fossa is separated via the lesser wing of the sphenoid

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14
Q

Types of major sutures and the bones that they contact

A

Coronal: frontal and parietal bones

Sagittal: two parietal bones

Sphenoparietal: sphenoid and parietal bones

Squamosal: squamous portion of the temporal bone and the parietal bone

Lambdoidal: parietal and occipital bones

Occipitomastoidal: mastoid process of the temporal bone and the parietal bone

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15
Q

Metopic suture

A

Generally fuses at birth and separates the frontal bone into two sides

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16
Q

Fontanelles

A

Areas of incomplete cranial suture formation that extend into early ages of birth

  • don’t fuse immediately at birth to allow brain to hypertrophy and grow during the early years
17
Q

Extranumerary bones

A

Small bones in between sutures that form due to cranial remodeling during childhood

18
Q

Functional matrix hypothesis

A

Cranium can be broken down into a number of functional units each responsible for housing a soft tissue “matrix”

  • growth in each functional unit is controlled and directed based on the underlying soft tissues associated with the functional units
  • ultimately cranial bone growth is a compensatory response to morphological change to the brain/glands/tissues
  • The brain essentially grows and shapes the skull*
19
Q

Functional units in the functional matrix hypothesis

A

Functional units:

  • neurocranium: house and protect brain
  • orbit: house and protect eye
  • nasopharynx: olfaction and warming/moistening air for breathing
  • oral cavity: processing food and communication
  • facial buttress system: every other function of the head
  • a functional unit is determined by the glands, neurovasculature, muscles and functional constraints from neighboring units*
20
Q

Neurocranium bones that grow via intramembranous growth

A

Incus

21
Q

Viscerocranium bones that grow via intramembranous growth

A

Everything except incus, stapes malleus, hyoid and styloid process

22
Q

Viscerocranium bones that grow via endochondral growth

A

Incus, stapes, malleus

Hyoid bone

Styloid process of temporal bone

23
Q

Neurocranium bones that grow via intramembranous growth

A

Frontal

Squamous temporal

Greater wing of the sphenoid

Parietal bones

Posterior occipital

24
Q

Neurocranium bones that grow via endochondral growth

A

Cribriform plate of the ethmoid

Petrous/mastoid of the temporal

Cranial base of the occipital

Sphenoid bone (except the greater wing and pterygoids)

25
Q

What are the fontanelles of the skull?

A

Anterior

Posterior

Sphenoidal (2)

Mastoidal (2)

  • A total of 6 fontanelles*
  • they are fibrous layers of the skull until the sutures form
26
Q

Anterior cranial fossa

A

Contains frontal lobe of cerebrum

26
Q

Middle cranial fossa

A

Contains temporal lobe of cerebrum

27
Q

Posterior cranial fossa

A

Contains cerebellum, pons, medulla oblongata

28
Q

80% of brain growth occurs when during development?

A

First 3 years of life

29
Q

Bones of the orbit

A

Frontal

Sphenoid

Ethmoid

Zygomatic

Maxilla

Lacrimal

Palatine

30
Q

What bones make up the nasopharynx

A

Ethmoid

Vomer

Maxilla

Nasal

Lacrimal

Sphenoid

Palatine

Inferior nasal concha

31
Q

Clinical significance of the sella turcica

A

Middle portion of the middle cranial fossa that houses the pituitary gland

32
Q

Endochondral vs intramembranous

A

Endochondrial growth is done via a cartilaginous precursor that ossifies over time

Intramembranous growth is done via direct mesenchymal condensations no cartilage