6. The Skull Flashcards
Identify the 2 parts of the skull.
- (in orange) VISCEROCRANIUM: facial skeleton and jaw bone = 14 bones
- NEUROCRANIUM: holds the brain = 8 bones
How many bones does the skull have?
22
Idenitfy the various parts of the neurocranium.
- red: PARIETAL bones (2 bones)
- yellow: OCCIPITAL bone (1)
- orange: FRONTAL bone (1)
- blue: TEMPORAL bones (2)
- purple: sphenoid bone (eyes and pituatary gland)
- green: ethnoid bone (nose)
What are sutures?
solid fibrous joint
Identify the various sutures of the skull.
What is the structure in yellow?
- SAGITTAL (connects 2 parietal bone)
- CORONAL (connects frontal and parietal)
- LAMBOID
yellow: calvaria (skull cap)
What is the strucure pointed at? What attaches there?
OCCIPITAL PROTUBERANCE: nuchal ligament attaches there
What is the structure circled?
where parietals and occipital meet
What is the strucure circled?
PTERION: where frontal, sphenoid, parietal and temporal meet
Describe the neonatal skull and the dangers of it.
neonatal skull: small visceriocranium and large neurocranium
due to head of baby, its hard to get baby out of mom because it is big => has soft spots (where bones have not joined yet) =fontanelles
Extraction may require forceps or vacuum that can put pressure on facial nerve (CNVII) (near ear): which can lead to facial nerve palsy (curves by itself)
What are cranial nerves?
nerves that come from the brain
Identify the different fossas of the skull
FROM ANT TO POST (ALSO FROM SUP TO INF IN HEIGHT)
- ANTERIOR cranial fossa (yellow)
- Middle cranial fossa (green)
- posterior cranial fossa (blue)
What type of bones is found in the anterior cranial fossa (3)?
- orbital plate (frontal bone) for eyes
- cribiform plate (ethomoid bone) (one with little hole for nose)
- sphenoid bone (lesser wing)
What type of bones are found in the middle cranial fossa (3)?
- sphenoid bone (greater wing)
- hypophyseal fossa (where pituatary gland sits)
- temporal bone (squamous and petrous parts)
What type of bones are found in the posterior cranial fossa (2)?
- temporal bone (petrous part)
- cereballar fossae (occipital bone)
Idenitfy the white hole. What is its function?
foramen magnum: where spinal cord goes out of skull
Identify these structures.
Green: ethmoid bone (has hole for smell)
top arrow: crista gali: extension of midline
lower arrows: cribiform foramina (holes!)
Idenitfy the various structures.
top arrow: crista gali
middle arrow: ethomoid hair cells
bottom arrow: nasal conchae (superior and middle) (superior is smaller than middle)
blue: superior part of nasal cavity
yellow: medial wall of orbit
Identify the various structures of the sphenoid bone.
a. lesser wing
b. greater wing
c. body
d. medial pterygoid plate
e. lateral pterygoid plate
f. pterygoid process
g. superior orbital fissures (for nerves for eyes)
h. orbital plate (posterior part)
i. sella turcica (boney prominence)
j. hypophyseal fossa (where pituatary gland is)
k. optic canals (for optic nerve cnii)
Identify the parts.
top arrow: cerebrum
bottom arrow: cerebellum
What is the difference between the 2 parts of the temporal bone?
squamous: flat and smoot
petrous: bumpy and houses the inner and middle ear (why its thicker)
Identify the various parts
in blue: temporal bone
in yellow: occipital bone
only the petrous bone (temporal bone) is part of the posterior cranial fossa
What does the cerebellar fossa hold?
cerebellar fossa in posterior cranial fossa (part of occipital bone) holds the cerebellum
Identify the various parts of the temporal bone.
A) squamous part (lateral wall of skull)
B) petrous part
C) tympanic part
D)external acoustic meatus
middle and inner ear housed by petrous
What are the arrows pointing at? What type of bone is it? What runs through the foramina?
Cribiform foramina (nose!) = ethnoid bone
Olfactory nerve (CN I) runs through the cribiform foramina
Identify the cranial foramina in the anterior and middle foramina and the what goes through each formina
mandibular is V3
Where does the external carotid a travel to?
to the face
Explain the trajectory of the internal carotid artery once its entered the skull.
the internal carotid artery goes tobrain via the carotid canal then entering the foramen lacerum
at the base of the internal artery rught when it enters the foramen lacerum: there is a ligament that forms that allows the artery to expand and compress in the bony canal
Identify the various cranial foramina in the posterior cranial foramina.
What supplies blood to the brain?
2 vertebral arteries (post), 2 internal carotids (ant)
What covers the cranial foramina?
meninges
Identify the various parts of the base of the skull
What is the cheekbone composed of?
the maxilla (2) split at the palatine process:
it has the soft palet further down from the hard palet= palatine bone
How do the styloid and mastoid bone of the temporal bone differ?
styloid more torwards midline and pointier
Identify the foramen in blue. What goes through this foramen?
stylomastoid foramina
the facial nerve extis through the stylomastoid foramina and then travels into the internal acoustic meatus
Why are babies prone to facial palsy?
the facial nerve is not protected as the mastoid process is not fully developped => giving birth with sunction or clamps can harm the exposed facial n
Identify the various bones of the viscerocranium.
- orange: nasal bones (2)
- red: maxilla bones (2)
- green: lacrimal bones (2)
- iyellow: inferior nasal conchae . (2) (middle and superior are part of the ethnoid bone)
- purple: vomer bone (bottom 1/2 of septum)
- palatine bones (2)
- blue: zygomatic bones (2)
- pink: mandible
How does sinus cold occur?
the maxilla has many holes in it: the nasal cavity can drain into the maxilla (mucus)
Where are the lacrimal bones situated?
at the tearducts (medial of eye cavity)
Explain the processes shown here.
- coming off of the zygomatic bones: temporal process
- coming off of the temporal bone: the zygomatic process
temporal process + zygomatic process = zygomatic arch (in red)
Identify the various parts of the mandible.
a. body
b. ramus
c. head
d. condylar process
e. coronoid process (more anterior)
f. alveolar processes ( for roots of teeth)
orange: mental process (chin)
red: mental foramina: mental n runs through it (for sensation of skin)
blue: angle (more streamline in babies)
green: mandibular notch
What inserts onto the coronoid process of the mandible?
temporalis muscle
Identify this joint and the ligaments that support it. What type of joint is it?
TEMPOROMANDIBULAR JOINT
between head of mandible (off of condylar process) and temporal bone
lateral ligament and joint capsule protect it
=modified synovial joint (hinge but can be more)
How does the temporomandibular joint differ when the mouth is open or closed? What is lock jaw?
open mouth: head of mandible translates forward onto the articular tubercle for extra opening
yellow: mandibular fossa
red: articular disc
lock jaw: moves too anterior and gets stuck
