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143 Cards in this Set
- Front
- Back
what forms the forehead skeleton?
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squamous part of the frontal bone
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squamous
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flat
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squamous frontal bone articulates winferiorly with:
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nasal and zygomatic bones (inferiorly); also articulates w/ lacrimal, ethmoid/sphenoid.
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metopic suture
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remnant of frontal suture in adults
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where is the metopic suture
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in the glabella
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glabella
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smooth and sl. depressed area between superciliary arches
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superciliary arch
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ridge just superior to supraorbital margin, extending laterally from glabella
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what is the frontal suture?
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the dividing line between the frontal bones in fetal cranium
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intersection of frontal and nasal bones:
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nasion, aka bridge of the nose
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supraorbital margin:
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angular boundary between squamous and orbital parts of the frontal bone
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what passes through the supraorbital foramen?
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Supraorbital nerve and vessels
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What holes reside in the orbits?
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-Superior/inferior orbital fissures
-Optic canals |
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These bones form the prominence of the cheeks:
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Zygomatic bones
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Small hole in the lateral zygomatic bone:
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Zygomaticofacial foramen
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Zygomatic bones articulate with:
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-frontal
-sphenoid -temporal -maxillae |
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Anterior nasal opening in cranium:
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piriform aperture
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what divides the nasal cavity into right/left parts?
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nasal septum; connects the vomer and perpendicular plate of ethmoid.
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what form the upper jaw?
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maxillae
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what are alveoli in regard to maxillae?
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the tooth sockets
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what supports the alveoli?
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alveolar processes - on the maxillae; also suppor the teeth in the maxillae.
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what forms the infraorbital margins?
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maxillae
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what hole is found inferior to each orbit?
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infraorbital foramen
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what passes through the infraorbital foramen?
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infraorbital nerves/vessels
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what is the articulation btwn maxillae called?
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intermaxillary suture
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What makes up the lower jaw?
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mandible
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In the mandible what denotes:
-the horizontal part -the vertical part |
horizontal = body
vertical = ramus |
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what are the holes inferior to second premolars called?
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mental foramen
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what runs through the mental foramen?
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mental nerves/vessels
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what is the chin prominence called?
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mental protuberance
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what is the mandibular symphysis?
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the osseous union where the halves of the infantil mandible fuse.
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what are fractures of the maxillae called?
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Le Fort fractures
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What is a Le Fort I fracture?
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Horizontal fracture of maxillae, passing above the alveolar processes.
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What is a Le Fort II?
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a break passing from postero-lateral side of the maxillary sinuses, up to the bridge of the nose.
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What is the result of a LeFort II?
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the entire central part of the face seperates from the cranium.
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What is a Le Fort III fracture?
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horizontal fracture thru superior orbital fissures, ethmoid, and nasal bones;
Laterally extends thru sphenoid greater wings and frontozygomatic sutures |
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what is the result of a lefort III?
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the MAxillae and Zygomatic bones separate from the cranium.
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How do mandible fractures usually present?
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As a double fracture - one on either side of the jaw.
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How does a hard blow to the jaw usually affect it?
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Fractures the mandibular neck, and the mandibular body in the opposite canine tooth region.
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What type of fracture is associated with the coronoid process?
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a single fracture - fairly uncommon.
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What causes alveolar bone resorption? What results?
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Extraction of teeth; causes alveolar process resorption, so mental foramen move superiorly.
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What can happen if the mental foramen move up on the mandible?
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Disappearance; the mental nerves can be exposed and injured.
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What is mandibular prognathism and what causes it?
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Overclosure of the jaw - due to the loss of all the teeth, which decreases the face vertically.
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What forms the boundaries of the temporal fossa?
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Superior/posterior = superior adn inferior temporal lines
Anterior = frontal bone + zygomatic bone Inferior = Zygomatic arch |
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What part of the brain does the superior border of the temporal fossa correspond to?
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The inferior limit of the cerebral hemisphere.
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What makes up the zygomatic arch?
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Posterior: Temporal process of zygomatic bone
Anterior: Zygomatic process of temporal bone |
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Where is the pterion located?
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Anterior temporal fossa, 3-4 cm above zygomatic arch midpoint.
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What is the pterion?
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H-shaped union of the frontal, parietal, sphenoid (greater wing) and temporal bones.
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what is a meatus?
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A canal
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What is the entrance to the eardrum consist of?
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-External acoustic opening
-External acoustic meatus -Tympanic membrane |
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What type of fracture usually results from a hard blow to thinner areas of calvaria?
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Depressed - a bone fragment presses inward, may injure brain
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What is the most frequent type of depressed calvarial fracture?
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Linear - it occurs at the point of impact, but fracture lines radiate outward from it.
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What is a comminuted fracture?
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One in which bone is broken into several pieces.
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What is a contrecoup fractuer?
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One in which no fracture occurs at impact site, but on opposite side of the cranium.
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What fracture of the skull can be life-threatening especially?
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Fracture of the pterion.
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Why is a pterion fracture so threatening?
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Because it overlies the anterior branches of middle meningeal vessels.
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Where exactly are the middle meningeal arteries located?
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In grooves inside the lateral calvaria wall.
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What results from a hard blow to the pterion?
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Fracture of thin bones, rupture of mid. mening. aa anterior branch, and hematoma.
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What is the occipital aspect of the cranium composed of?
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-Occiput (protuberance)
-Parts of parietal bones -Mastoid parts of temporals. |
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What is the inion?
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a craniometric point defined by the tip of the external protuberance.
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What is the external occipital crest?
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Line descending from the inion to foramen magnum
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What is the line extending laterally from the inion called?
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Superior nuchal line
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What is the lambda?
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The junctio between the sagittal and lambdoid sutures.
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What are accessory bones called, and where are they usually found?
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Sutural bones - found near labmda or mastoid process.
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What are parietal eminences?
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Places on the parietal bones where they become broader and more oval.
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What suture separates the frontal and parietal bones?
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Coronal suture.
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What suture separates the parietal bones?
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Sagittal
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What suture seperates the parietal and temporal bones from occipital?
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Lambdoid
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What forms the bregma?
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Intersection of the sagittal and coronal sutures.
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What is the vertex?
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Most superior point of calvaria; near midpoint of sagittal suture.
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What are emisary foramina?
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Irregular, highly variable foramina that transmit emissary veins.
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What are emissary veins?
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Veins connecting scalp veins to venous sinuses of the dura mater.
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What emissary foramen may be found in the parietal bones?
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ironic, but its the parietal foramen.
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What makes up the external inferior surface of the cranium?
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alveolar arch of the maxilla - not the mandible.
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What forms the hard palate?
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-Palatine processes of maxillae
-Horizontal plates of palatines |
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What is the free on the back of the hard palate called?
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Nasal spine - projects posteriorly to meet the vomer.
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What are choanae?
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The posterior nasal apertures that are just superior to the back of the hard palate.
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What seperates the 2 choanae?
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A quadrilateral bone, the VOMER.
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Vomer means
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plowshare
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What is the sphenoid wedged between?
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Frontal, temporal, and occipital bones.
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In general what does the sphenoid consist of?
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-A body
-3 pairs of processes: Greater wings, lesser wings, pterygoid processes. |
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Where are the greater and lesser wings of the sphenoid?
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Spreadding laterally; the lesser wings are anterior to the greater.
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What makes up the pterygoid process?
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Medial/Lateral Pterygoid wings
- hang down inferiorly from the body and the other wings. |
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What lies in a groove just posterior/medial to sphenoid spine?
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The cartilaginous part of the pharyngotympanic tube. It's under the articulation of the sphenoid greater wing and petrous part of temporal bone.
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What are mandibular fossae?
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Depressions in squamous temporal bones created by mandibular condyles when mouth is closed.
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What forms the posterior portion of the cranial base?
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Occipital bone + sphenoid
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What passes through foramen magnum?
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1. Spinal cord
2. Meninges 3. Vertebral arteries 4. Ant/post spinal arteries 5. Accessory nerve CN XI |
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Where does the cranium and vertebral column articulate?
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At the occipital condyles.
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What structures pass through the jugular foramen in the cranium?
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-Internal Jugular vein
-CN IX - CN XI |
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What passes through the stylomastoid foramen?
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the facial nerve and stylomastoid artery.
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Where is the stylomastoid foramen?
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Just posterior to the styloid process on the temporal bone.
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What are the fossae on the internal surface of the cranial base?
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1. Anterior cranial fossa
2. Middle cranial fossa 3. Posterior cranial fossa |
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What bones form the anterior fossa?
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1. Frontal bone
2. Ethmoid bone 4. Body/lesser wings of sphenoid. |
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What is the frontal crest?
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Median bony extension of the frontal bone
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What is at the base of the frontal crest?
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Foramen cecum
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What is foramen cecum's purpose?
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Gives passage to vessles in fetal development; insignificant postnatally.
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what structure is just posterior to foramen cecum?
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Crista galli
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what lies on either side of crista galli?
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the cribiform plate of the ethmoid bone.
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what passes through the cribiform plate?
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Olfactory nerves for CN I, on their way to the Olfactory Bulbs that lie on top of the plate.
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What makes up the central part of the middle cranial fossa?
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Sella turcica
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what separates the middle cranial fossa from the anterior?
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Sphenoidal crests (laterally)
Sphenoidal limbus (centrally) |
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What makes the sphenoidal crests?
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Sharp posterior borders of the lesser wings.
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What structure do the sphenoidal crests end in posteromedially?
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Anterior Clinoid processes - the bedposts at the head of the bed.
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What is just posterior to the sphenoid limbus?
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Prechiasmatic sulcus
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What does the prechiasmatic sulcus extend between?
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the optic canals
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What bones make up the lateral borders of the middle fossa?
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-Sphenoid greater wings
-Squamous temporal bones |
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What makes up the posterior border of the middle fossa?
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-Petrous part of the temporals
-Dorsum sellae (back edge of sella tursica) |
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What is sella turcica?
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The saddle of the sphenoid
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What surrounds sella turcica at each corner?
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Clinoid processes - the bedposts.
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What makes up the seat of sella turcica?
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The hypophysicla fossa - the bed of the pituitary gland.
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What 3 things compose sella turcica?
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1. Tuberculum sellae (the horn)
2. Hypophysial fossa (seat) 3. Dorsum sellae (back edge) |
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What 4 foramina perforate the sphenoid greater wings on either side of sella turcica?
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1. Superior orbital fissure
2. Foramen rotundum 3. Foramen ovale 4. Foramen spinosum |
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Where exactly is superior orbital fissure located? What passes through it?
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Between the greater/lesser wings
-Opthalmic veins -Opthalmic nerves (3, 4, V1, 6) -Sympathetic opthalmic nerves |
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Where is foramen rotundum?
What passes through it? |
Just behind the medial part of superior orbital fissure.
-Transmits V2 |
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Where is foramen ovale?
What passes through it? |
Just behind/lateral to foramen rotundum.
-Transmits V3, and a small acessory meningeal artery. |
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Where is foramen spinosum found?
What passes through it? |
Just behind/lateral to foramen ovale.
-Transmits Middle Meningeal arteries and meningeal branch of mandibular nerve (?). |
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What is foramen lacerum?
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An artifact resulting from dead, dried up cranium; in life it's filled with cartilage.
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What passes above the cartilage that fills foramen lacerum?
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Internal carotide artery
-Accompanying sympathetic/venous plexus - All on the way to the anterior boundary foraman. |
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What groove extends postero-laterally from foramen lacerum?
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The groove for the greater petrosal nerve.
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What brain structures lie within the posterior cranial fossa?
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-Cerebellum
-Pons -Medulla oblongata |
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What marks the incline of dorsum sellae medially?
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The clivus - leads to foramen magnum.
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What are the 2 large bilateral concave impressions of the posterior cranial cavity?
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Cerebellar fossae
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What landmark leads posteriorly from foramen magnum, dividing the cerebellar fossae?
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Internal occipital crest - ending in the internal occipital protuberance.
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What hole is found at the base of the petrous ridge?
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Jugular foramen
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What is transmitted through the jugular foramen?
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-Sigmoid sinus - as the IJV
-Several cranial nerves |
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What hole is just in front of and above the jugular foramen?
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Internal acoustic meatus
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What does the internal acoustic meatus transmit?
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-Facial nerve
-Vestibulocochlear nerve -Labyrinthine artery |
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What goes through the hypoglossal canal?
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The hypoglossal nerve :)
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What is the structure of the calvaria bones like?
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3 layered:
-Internal table of compact bone -External table of compact bone -Diploe in between |
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What is diploe?
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Cancellous bone that contains red bone marrow in life.
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By what type of ossification does the calvaria and part of cranial base form?
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Intramembranous
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By what type of ossification does the rest of cranial base form?
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Endochondral
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What sutures are present in infants that arent in adults?
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-Frontal (mid frontal bone)
-Internasal -Intermaxillary -Mandibular symphysis |
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What processes in the cranial bones are lacking in infants at birth?
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Mastoid processes
Styloid processes |
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What is the physiological result of lacking mastoid processes?
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The facial nerves emerge close to the surface of the skin when they go through stylomastoid foramina.
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What can be a pathological result of lacking the processes?
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Forceps can damage teh facial nerve, or ear surgery.
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What causes these processes to develop?
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Development of sternocleidomastoid muscles and their insertion on the mastoid processes of temporal bones.
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What 4 fontanelles are present in infants at birth?
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-Anterior
-Sphenoidal -Mastoid -Posterior |
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What 3 things can be determined by palpating fontanelles?
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1. Progress of growth of parietal/frontal bones
2. Degree of hydration 3. Level of intracranial pressure |
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What is the largest fontanelle and where is it located?
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Anterior - located at future bregma - junction of coronal and sagittal sutures.
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When does the anterior fontanelle no longer palpable?
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18 months
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When do the frontal suture fuse completely?
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by the 8th year; except in 8% of people, who retain a metopic suture.
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Where is the posterior fontanelle located?
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At the future lambdoid
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What is the advantage of these loose connections and soft cranial bones in infants?
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Molding - changes in calvaria shape during birth
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