L9: Neuro/viscerocranium Flashcards
What is the viscerocranium? What is the neurocranium? What embryological structures are these derived from?
- Viscerocranium refers to the facial skeleton that is derived from the pharyngeal arches.
- Neurocranium refers to cranium that houses brain and is derived from paraxial mesoderm.
Components of viscerocranium?
- Mandible
- Maxilla
- Zygomatic
- Nasal
- Ethmoid (except cribriform plate)
- Lacrimal
- Pterygoid process of sphenoid
- Tympanic part and styloid process of temporal bone
- Palatine
- Vomer
- Inferior Nasal Concha
Components of neurocranium?
- Frontal
- Petrous, mastoid and squamous parts of temporal bone
- Occipital
- Parietal
- Sphenoid
- Cribriform plate of ethmoid
What are calvaria?
- Unique plate-like bones comprised of inner and outer tables with diploë, marrow rich structure that are primary sources of RBCs, of frontal, parietals, occiptal and squamous temporal bones.
What are diploë?
- Marrow rich structure in calvaria that are sources of RBCs.
Use netter’s flash cards to identify bones and features of neuro/viscerocranium.
- Just do it!
What are the bones of the orbit?
- Frontal
- Maxilla
- Zygomatic
- Sphenoid
- Ethmoid
- Palatine
- Lacrimal
What are the bones of the nasal cavity?
- Maxilla
- Ethmoid
- Lacrimal
- Nasal
- Vomer
- Palatine bones
- Sphenoid (medial pterygoid plates)
- Inferior nasal concha
Name paranasal sinuses.
- Frontal
- Maxillary
- Sphenoidal
- Ethmoid air cells
Describe Le Fort Fractures I, II and II.
I: horizontal fracture detaching maxilla along the nasal floor
II: pyramidal fracture includes both maxillae, nasal bones, infraorbital rims and orbital floors
III: includes Le Fort II and both zygomatic bones
Describe where each of the following sutures occur: Sagittal Coronal Lambdoidal Metopic/frontal Squamosal Occipitomastoidal Sphenoparietal
- Sagittal: along sagittal plane bw parietal bones
- Coronal: along coronal plane bw frontal and parietal bones
- Lambdoidal: between occiptal bone and barietal bones
- Metopic: between two growth centers of frontal bone along sagittal plane. Usually fully fused and not seen
- Squamosal: bw squamous part of temporal and parietal bone
- Occipitomastoidal: bw occipital and petrous part of temporal bone
- Sphenoparietal: bw sphenoid and parietal bones
What is craniosynostosis?
- Deformities result from premature closes of cranial sutures, appear to be genetic in nature.
What are the types of craniosynostoses? Describe.
- Scaphocephaly: fusion of sagittal suture (most)
- Brachycelphaly: fusion of coronal suture
- Plagiocephaly: fusion of 1 side of either coronal or lambdoidal suture
- Trigonocephaly: fusion of metopic suture
- Kleeblattschädel (clover leaf): fusion of coronal, lambdoidal and sagittal sutures (rare)
What is microcephaly? Hydrocephaly?
- Microcephaly: number of congenital issues cause this. Premature fusion of all sutures and fontanelles in early development preventing brain and cranium from growing. Result = severe retardation.
- Hydrocephaly: congenital inability to absorb CSF resulting in overproduction and increased ICP causes growth and expansion of calvarial bones along suture.
Describe cranial landmarks.
- Bregma: pt where sagittal and coronal sutures meet
- Lambda: pt where sagittal and lambdoidal sutures meet
- Glabella: most anterior midline pt of frontal bone
- Nasion: intersection pt of nasofrontal suture and midsagittal plane
- Pterion: intersection of frontal, temporal, sphenoid and parietal bones
Describe Bregma.
- Bregma: pt where sagittal and coronal sutures meet
Describe Lamda:
- Lambda: pt where sagittal and lambdoidal sutures meet
Describe Glabella:
- Glabella: most anterior midline pt of frontal bone
Describe Nasion:
- Nasion: intersection pt of nasofrontal suture and midsagittal plane
Describe Pterion:
- Pterion: intersection of frontal, temporal, sphenoid and parietal bones
What are the neurocranial fossa? Describe contents of each.
- ) Anterior cranial fossa: frontal lobe
- ) Middle cranial fossa: temporal lobe
- ) Posterior cranial fossa: cerebellum, pons, medulla oblongata
From which foramen do the cranial nerves transverse?
a.) CN I: cribriform plate foramina
b.) CN II: optic canal
c.) CN III: superior orbital fissure
d.) CN IV: superior orbital fissure
e.) CN V:
V1: supraorbital foramen, superior orbital fissure
V2: infraorbital foramen, inferior orbital fissure, greater/lesser palatine foramen, incisive foramen, foramen rotundum
V3: mental foramen, foramen ovale, foramen spinosum
f.) CN VI: superior orbital fissure
g.) CN VII: internal and external acoustic meatus, stylomastoid foramen
h.) CN VIII: internal and external acoustic meatus
i.) CN IX: jugular foramen
j.) CN X: jugular foramen
k.) CN XI: jugular foramen, foramen magnum
l.) CN XII: hypoglossal canal
What CNs appear in the following foramina?
a. ) supraorbital foramen
b. ) infraorbital foramen
c. ) mental foramen
d. ) greater and lesser palatine foramen
e. ) incisive foramen
f. ) stylomastoid foramen
g. ) cribriform plate foramina
h. ) optic canal
i. ) superior orbital fissure
j. ) inferior orbital fissure
k. ) foramen rotundum
l. ) foramen ovale
m. ) foramen spinosum
n. ) foramen lacerum
o. ) carotid canal
p. ) foramen magnum
q. ) jugular foramen
r. ) hypoglossal canal
s. ) internal/external acoustic meatus
- supraorbital foramen: CN V1
- infraorbital foramen: CN V2
- mental foramen: CN V3
- greater and lesser palatine foramen: CN V2
- incisive foramen: CN V2
- stylomastoid foramen: CN VII
- cribriform plate foramina: CN I
- optic canal: CN II
- superior orbital fissure: CN III, CN IV, CN V1, CN VI
- inferior orbital fissure: CN V2
- foramen rotundum: CN V2
- foramen ovale: CN V3
- foramen spinosum: CN V3
- foramen lacerum: no CN
- carotid canal: no CN
- foramen magnum: CN XI
- jugular foramen: CN IX, CN X, CN XI
- hypoglossal canal: CN XII
- internal/external acoustic meatus: CN VII, CN VIII
What structures (nerves, veins, arteries) appear in the following foramina?
a. ) supraorbital foramen
b. ) infraorbital foramen
c. ) mental foramen
d. ) greater and lesser palatine foramen
e. ) incisive foramen
f. ) stylomastoid foramen
g. ) cribriform plate foramina
h. ) optic canal
i. ) superior orbital fissure
j. ) inferior orbital fissure
k. ) foramen rotundum
l. ) foramen ovale
m. ) foramen spinosum
n. ) foramen lacerum
o. ) carotid canal
p. ) foramen magnum
q. ) jugular foramen
r. ) hypoglossal canal
s. ) internal/external acoustic meatus
- supraorbital foramen: CN V1
- infraorbital foramen: CN V2
- mental foramen: CN V3
- greater and lesser palatine foramen: CN V2 with greater and lesser palatine vessels
- incisive foramen: CN V2, sphenopalatine vessels
- stylomastoid foramen: CN VII
- cribriform plate foramina: CN I
- optic canal: CN II, ophthalmic artery
- superior orbital fissure: CN III, CN IV, CN V1, CN VI
- inferior orbital fissure: CN V2
- foramen rotundum: CN V2
- foramen ovale: CN V3, accessory meningeal a
- foramen spinosum: CN V3, middle meningeal a
- foramen lacerum: no CN, internal carotid
- carotid canal: no CN, internal carotid
- foramen magnum: CN XI, medulla oblongata, vertebral arteries
- jugular foramen: CN IX, CN X, CN XI, inferior petrosal sinus becomes int jugular v, posterior meningeal artery
- hypoglossal canal: CN XII
- internal/external acoustic meatus: CN VII, CN VIII
