The Cranium (Quiz 1) Flashcards
The anatomical position of the skull is in what plane?
orbitomeatal plane (frankfort horizontal plane)
(natural carrying angle of head and face)
The orbitomeatal plane (frankfort horizontal plane) is extending from the superior border of ____________________ of the temporal bone to the inferior border of the ___________
external auditory meatus (EAM), orbit (zygomatic and maxilla)
What are the 2 divisions of the skull?
neurocranium and viscerocranium
How many bones are there in total for the skull?
22
The neurocranium is the _____________ and ____________ part of the skull and makes up 8 bones (4 singular on midline, and 2 paired)
superior, posterior
note: the 2 paired bones are the parietal and temporal bones
The viscerocranium is the _____________ part of the skull and makes up 15 bones
anterior (eyes, mouth, nose)
The neurocranium is a bony case of the brain and the….
meninges
What are the 2 parts of the neurocranium?
calvaria (dome like roof) and basicranium (floor or base)
What bones make up the calvaria (dome like roof of the neurocranium)?
primarily flat bones
What is the calvaria (dome like roof of the neurocranium) formed by?
intramembranous ossification
What is the calvaria (dome like roof of the neurocranium) held together by?
sutures
What bones make up the basicranium (floor or base of the neurocranium)?
primarily irregular bones w/ flat portions
What is the basicranium (floor or base of the neurocranium) formed by?
endochondral ossification (has 3 paired fossae- anterior, middle, and posterior)
What are the 4 singular bones of the neurocranium?
frontal, occipital, ethmoid, and sphenoid
What are the flat bones of the neurocranium (singular only)?
frontal bone and occipital bone
What are the irregular bones of the neurocranium (singular only)?
ethmoid bone and sphenoid bone
What are the 2 paired bones of the neurocranium?
parietal bones and temporal bones
What are the flat bones of the neurocranium (paired bones only)?
parietal bones
What are the irregular bones of the neurocranium (paired bones only)?
temporal bones (has large flat portion)
What is another name for viscerocranium?
splanchnocranium
(there are 14 bones, 15 with ethmoid bone, 2 of them are singular on the midline (3 with ethmoid), and 6 paired)
Which bone is a part of both the neurocranium and viscerocranium?
ethmoid bone
The viscerocranium developed from mesenchyme of the _______________________
embryological pharyngeal arches
The viscerocranium forms the oral cavity, nasal cavity, and most of the…
orbits
What are the 3 singular bones of the viscerocranium?
vomer, mandible, and ethmoid
What is the flat singular bone of the viscerocranium?
vomer
What are the irregular singular bones of the viscerocranium?
mandible and ethmoid bone
What are the 6 paired bones of the viscerocranium?
1) nasal
2) lacrimal
3) inferior nasal conchae
4) maxilla
5) zygomatic
6) palatine
What are the flat paired bones of the viscerocranium?
nasal and lacrimal
What are the irregular paired bones of the viscerocranium?
1) inferior nasal conchae
2) maxilla
3) zygomatic
4) palatine
What are the names of the neurocranial sutures?
-coronal/frontal
-sagittal
-squamosal
-lambdoidal
The viscerocranial sutures are named for….
bones they join
The neurocranium contains the basilar suture. What is another name for this and when is it fused?
Test q
spheno-occipital
fusion forms foramina lacera (closed by cartilage)
fused by age 18 typically (gives brain time to grow)
Primary synchondroses come from…..
Cartilage
TMJ has a fibrocartilage disc in the _______________ fossa. This is internal to the joint capsule
Mandibular
The TMJ has a temporomandibular ligament that is also called the ______________________ ligament.
External lateral ligament
The TMJ has a temporomandibular ligament that is also called the external lateral ligament. It is found at the lower articulation tubercle of zygomatic arch to the posterior and lateral borders of the….
Neck of the mandible
The TMJ has a temporomandibular ligament that is also called the external lateral ligament. What is the function of this ligament?
To prevent posterior displacement of the mandible
The TMJ has syndesmoses (ligaments) external to the joint capsule, what are the two we talked about in class?
-stylomandibular ligament
-sphenomandibular ligament (also known as the internal lateral ligament)
The TMJ has 2 ligaments external to the joint capsule. One of them is the stylomandibular ligament. It is found at the ____ of the stylomandibular process to the angle and posterior border of angle of the mandible
Apex
The TMJ has 2 ligaments external to the joint capsule. One of them is the stylomandibular ligament. What is its function?
To limit mandibular movement
The TMJ has 2 ligaments external to the joint capsule. One of them is the sphenomandibular ligament (also called the internal lateral ligament). It is found at the spine of the sphenoid (___________________________) to lingula of mandible
Posterior to foramen spinosum
The TMJ has 2 ligaments external to the joint capsule. One of them is the sphenomandibular ligament (also called the internal lateral ligament). What is its function?
Primary passive support of the mandible
Is this a male or female skull?
Male
Does the cranial wall vary in thickness?
Yes!
The thinner areas of the cranial wall are usually covered by what?
Muscles
The skull is generally thinner in who?
-thinner in females than males (females also have a rounder skull)
-thinner in children and elderly (elderly is bc of osteoporosis where there’s a loss of calcium)
Diploe bones are the layer of cancellous (spongy) bone between the outer layers of the bones of the…..
Calvaria
Basically:
Compact bone
Spongey bone
Compact bone
Diploe is spongey bone that contains what type of bone marrow?
Red bone marrow (erythrocytes are made here)
What veins are found at the Diploe (spongey bone of calvaria)? What do they do?
Diploic veins drain wastes from the dura mater
What are the thickened areas of bone formed to protect weaker regions called?
Buttresses
Buttresses are thickened areas of bone formed to protect weaker regions that transmit forces by bypassing the fragile bones of the ________ and ___________ reinforcing the jaw
orbit, nasal cavity
The zygomatic arch-lateral orbital margin buttresses is found at the lateral ____________ wall and lateral orbital wall, to the upper transverse maxillary and ________________
maxillary, orbital floor
The masticatory plates are also known as chewing plates and contain 4 buttresses.
1) lower transverse maxillary + palate
2) upper transverse mandibular
3) posterior vertical
4) ?
posterior maxillary
Where are the frontonasal buttresses found?
medial maxillary + medial orbital wall
The occipital buttresses are found laterally from the __________________ of the temporal bone and posteriorly from the ____________________ and EOP
mastoid process, inferior nuchal line
Where are the frontal buttresses found?
along the frontal eminences
What 7 bones make up the orbit?
Test q
-frontal
-maxillary
-zygomatic
-sphenoid
-palatine
-ethmoid
-lacrimal
The frontal bone is 1/7 bones that makes up the orbit. What part of the frontal bone makes up the orbit?
the orbital plate/process of the frontal bone
The maxillary bone is 1/7 bones that makes up the orbit. What part of the maxillary bone makes up the orbit?
the frontal plate/process of the maxillary bone
The sphenoid bone is 1/7 bones that makes up the orbit. What part of the sphenoid bone makes up the orbit?
greater wing of the sphenoid
What is the roof of the orbit?
frontal bone (specifically the orbital plate/process)
What is the floor of the orbit?
maxillary (frontal process)
What is the lateral wall of the orbit?
zygomatic bone
What is the posterior wall of the orbit?
sphenoid bone (greater wing)
What are the 2 posteriomedial walls of the orbit?
palatine and ethmoid
What is the anteriomedial wall of the orbit?
lacrimal
Nasolacrimal ducts run within the _____________________ to the inferior nasal meatus (tears drain into the meatus)
lacrimal foramen
Why is the eye fragile?
its made up of 7 bones, so blow out fractures are common when something gets past the buttresses because theres so many bones here, it makes it more vulnerable for fractures/bruising
Is the internal nasal septum bone or cartilage?
bone
What bone is the superior nasal septum (internal septum)?
perpendicular plate of the ethmoid bone
What bone is the inferior nasal septum (internal septum)?
vomer
Is the external nasal septum bone or cartilage?
cartilage
What cartilage is at the anterior plate of the external septum?
septal cartilage (hyaline)
What is the external nose called and what cartilage is there?
tip and ala (w/ very little elastic cartilage)
What is another name for the nasal conchae?
turbinates
What nasal conchae are a part of the ethmoid bone?
superior and middle nasal conchae
What nasal conchae is NOT a part of the ethmoid bone?
inferior nasal conchae
The nasal meati are found _________ each nasal conchae, respectfully. For example, the superior nasal meatus is found between the superior and middle nasal conchae.
below
What 2 structures are found within the middle nasal meatus?
ethmoid bulla and semilunar hiatus
What sinuses drain into the semilunar hiatus?
frontal, maxillary, and ethmoid sinuses
What are the 4 paranasal sinuses?
1) ethmoid
2) frontal
3) sphenoid
4) maxillary
The paranasal sinuses drain into the ________
nose (there are more specific locations for each one!)
Where does the ethmoid sinus drain into?
the middle and superior meatus
Where does the frontal sinus drain into?
the middle meatus
Where does the sphenoid sinus drain into?
the sphenoethmoidal recess (posterior to the superior concha)
Where does the maxillary sinus drain into?
the middle meatus
Tears drain from the ________________ (orbit) to the inferior nasal meatus
lacrimal foramen
T/F: all fluids are either expelled from the nose or swallowed
true!
What does pneumatized mean?
open air space, contains sinuses or air cells
What are the functions of pneumatized bones?
-lightening the skull (weight)
-warming/moistening air
-reverberate the voice
-resonate/projection
What sinuses get smaller with age?
frontal sinuses
The alveolar fossae in the maxillae may cause intrusions into the maxillary sinus and result in pain where?
tooth pain
The parotic sinus is found next to which gland?
parotid gland
Is the parotic sinus pneumatized?
yes
The parotic sinus is near the parotid gland and mastoid process. What are its air cells/sinus called?
mastoid air cells
The parotic sinus is connected to what? Additionally, what cranial nerve runs through here?
parotic sinus is connected to inner ear
CN VII runs through here
If there is inflammation at the parotic sinus, would it affect balance or hearing more?
balance more than hearing
What are the smallest bones of the body?
the ossicles (malleus, incus, stapes)
Are the ossicles a part of the skull structure?
no
Where are the ossicles housed?
inside petrous pyramid of the temporal bone
Are the ossicles paired or unpaired?
paired
What is another word for malleus?
hammer
The malleus/hammer is attached to the tympanic membrane by what joint?
test q
fibrous joint
What is another word for incus?
anvil
What is another word for stapes?
stirrup
The stapes is attached to the oval window of the vestibule of the labyrinth by what joint?
fibrous joint
What type of joints are between the ossicles?
synovial (saddle or ball and socket depending on location)
What is the smallest saddle joint in the body?
incudomallear
What is the smallest ball and socket joint in the body?
incudostapedial
The infratemporal fossa is the space between the ____________________ and _____________ bone
zygomatic arch, temporal
What muscle sits at the infratemporal fossa?
temporalis m.
What lies deep to the infratemporal fossa?
-pterygomaxillary fissure (border of opening)
-pterygopalatine fossa (space)
-sphenopalatine foramen (opening in the medial wall of the pterygopalatine fossa)
What are the functions of the fetal skull?
-protect brain
-collapse for birth canal
-growth for skull
-form facial openings
One of the functions of the fetal skull is to form facial openings. What are they?
-orbit (protection of ocule)
-oral cavity
-nasal cavity
What is the function of the oral cavity?
allows for mastication, deglutition, emission, tussis, and sucking
What is the function of the nasal cavity?
allows for venitilation and sternutation (sneezing)
Fetal skulls have “bossing” which is palpable where?
frontal, parietal, and occipital eminence
Where is the site of initial intramembranous ossification?
on flat bones of the neurocranium of a fetus
How many bones are a part of the neurocranium for a fetus?
9 (2 frontal bones)
How many bones are a part of the viscerocranium for a fetus?
15 (16 w/ ethmoid, 2 mandibular bones)
When do fetal neurocranial sutures begin to fuse and when are they completely fused?
begin fusing at around 24 y/o and fuse completely by 30-40 y/o
Do the neurocranial sutures disappear after they fuse?
potentially, they may never completely obliterate
What are the 4 sutures that can be seen sometimes even after fusing?
-coronal/frontal
-sagittal
-lambdoidal
-squamosal
What suture fuses at 18 y/o?
basilar suture
What suture fuses at 3-9 months of age?
metopic suture (makes 2 frontal bones into 1 bone!)
Babies are born with 2 mandibular bones. This is called symphysis menti, or mandibular symphysis once it becomes one bone. What age does it fuse and what cartilage is there?
fuses at 1-2 y/o
fibrocartilage is here and its synarthrotic
