Skull Flashcards
What can the neurocranium be divided into?
Calvaria and cranial base
What bones make up the anterior skull view?
-frontal (forehead)
-nasal (R/L on top of nasal cavity)
-maxilla (involved in eye socket, nasal cavity, and oral cavity/roof of mouth)
-zygomatic (part of eye socket and zygomatic arch/cheek bone)
-mandible (jaw)
What are the landmarks of the frontal bone?
-supraorbital foramen (hole above eye socket that allows nerve to pass sensory info to forehead/top of head)
-nasion (junction between R/L nasal bones and frontal bone)
-glabella (smooth surface above the nasion)
What is the landmark of the maxilla?
-infraorbital foramen (hole below eye socket that allows a nerve to spread sensory info to maxillary/mid region of the face)
What are the landmarks of the mandible?
-mental foramen (hole on mandible which allows a nerve to spread sensory info to the jaw)
-mental protruberance (bony prominence in front of lower jaw, chin)
What bones make up the lateral skull view?
-frontal-parietal-occipital-sphenoid (keystone of the skull)-temporal
: zygomatic arch (temporal and zygomatic bone form this)
: external acoustic meatus (opening to ear)
: mastoid process (bump on bottom of temporal)
: styloid process
-zygomatic
:zygomatic arch
What is the temporal fossa?
Landmark of lateral skull: depression/hollow located above zygomatic arch
What is the pterion?
Landmark of lateral skull: meeting/junction of the temporal, frontal, parietal and sphenoid
What is the squamous suture?
Landmark of lateral skull: meeting/junction between the temporal and parietal bones
What is the coronal suture?
Landmark of lateral skull: meeting/junction between frontal and parietal bones
What is the lambdoid suture?
Landmark of lateral and superior skull: meeting/junction between the occipital and parietal bones
What bones make up the superior skull view?
-parietal bones
-frontal bone
-occipital bone
What is the sagittal suture?
Landmark of the superior skull: meeting/junction between the right and left parietal bones
What is the coronal suture?
Landmark of superior skull: meeting/junction between the frontal and parietal bones
What is the bregma?
Landmark of superior skull: meeting/junction of the coronal and sagittal sutures
What is the lambda?
Landmark of superior skull: meeting/junction of the sagittal and lambdoid sutures
What bones make up the inferior view (cranial base) of the skull?
-occipital
-temporal
-sphenoid (keystone of the skull)
-maxilla (hard palate-more anterior)
-palatine (hard palate-more posterior)
What are the landmarks of the occipital bone?
-foramen magnum (large hole where spinal cord/brainstem pass through)
-EOP (external occipital protruberance), (bump on posterior base of skull)
What are the landmarks of the temporal bone?
-mastoid process
-styloid process
-external acoustic meatus
-stylomastoid foramen (opening between styloid process and mastoid process to allow cranial nerve 7 to pass to the face)
-jugular fossa/foramen (opening at junction between occipital and temporal bones for IJV/CN: 9,10,11)
-carotid canal (opening anterior to jugular fossa for ICA to supply blood supply to the brain)
What is the clinical application associated with the pterion (meeting point of the frontal, parietal, temporal, and sphenoid bones)?
The middle meningeal artery lies deep (beneath) the pterion
Because the pterion is the thinnest region of the skull, it is susceptible to fracture and trauma (which may lead to epidural hematoma-bleeding/damage to the middle meningeal artery)
What bones make up the internal view (cranial base) of the skull?
-anterior fossa
-middle fossa
-posterior fossa
ridges will divide the fossa in the cranial base
What are the landmarks of the anterior fossa?
-lesser wing of the sphenoid bone: surface of the “ridge” between anterior and middle fossa
-cribrifrorm plate of ethmoid bone: roof of the nose or nasal cavity, contains a bunch of small openings for CN1 to pass through/dangle at the top roof of the nose to transmit smell)
What are the landmarks of the middle fossa?
-greater wing of sphenoid: the sides of the “ridge” between the anterior and middle fossa
-optic canal: opening (can be found by following the lesser wing of sphenoid bone medially) which allows for CN2 (optic nerve) to pass from the brain to the eyeball/retina
-sella turcica: center of the cranial base “saddle” which holds/protects the pituitary gland
-foramen lacerum: opening filled with cartilage that acts as a floor/seal which allows CCA to run through and connect to the circle of willis
-superior orbital fissure: opening just below the lesser wing which allows CN 3,4,6 and V1 of CN5 to pass through to the eye socket (extraocular muscles), V1 of C5 will travel to the forehead using the eye socket as a pathway
-foramen rotundum: first opening posterior to the superior orbital fissure, opening for V2 of CN5 to make its way toward the maxilla/mid face
-foramen ovale: oval shaped opening for V3 of CN5 to make its way to the mandible
-foramen spinosum: small opening behind the foramen ovale which allows the middle meningeal artery to pass through
What are the landmarks of the posterior fossa?
-internal acoustic meatus: located in temporal bone ridge which contains CN7 (passing through to the face) and CN8 (supplies inner ear)
-jugular foramen: opening at the junction between temporal bone and occipital bone “kidney shaped”, allows for passage of IJV/ CN9, CN10, CN11
-hypoglossal canal: on occiptal bone, horizontal oriented opening that allows for CN12 to pass through the neck into the floor of the mouth
-foramen magnum: large opening in center of skull for spine/brainstem to pass through
