1a. Skull HAL - Acland Videos Flashcards
what 2 components is the skull composed of
cranium and facial skeleton
where does the occipital bone extend down to inferiorly
to the center of the inferior skull past the foramen magnum
what foramen does the occipital bone contain
foramen magnum
what is the occipital bone in front of the foramen magnum known as
what direction is the slope of this part and where is the slope
basilar part/base of occiput
slopes forwards deeply on the inside
what bony feature is on the anterior half of the foramen magnum
what other structure do they form
2 occipital condyles
forms the atlanto-occipital joints
what is the lump in the middle of the occipital bones posterior overhang
external occipital protuberance/inion
what is the name of the temporal bone where it converges with the occipital bone on the inferior side
petrous part
what is the name of the temporal bone where it is see laterally
squamous part
what is the mastoid process used for
name an example of its function
origin of muscles that move the head
sternocleidomastoid muscle
what is the zygomatic arch made up of in terms of the bones
termporal and zygomatic bones
what is are the 2 components that make up the temporal mandibular joint
underside of zygomatic arch root articulating with mandible condyle
what does the external auditory meatus lead to
middle ear
what is the feature at the base of the styloid process and what is it used for
stylo-mastoid foramen for facial nerve passage
what is the carotid canal used for
what structure is it medial to and what plane of the skull is it located on
passes forwards the internal carotid artery
medial to styloid process on inferior plane of skull
what part of the temporal bone contains the inner and middle ear structures
petrous part of the temporal bone
what is the groove behind the jugular foramen for
for the sigmoid sinus
what is the main venous drainage channel for the brain in terms of sinuses
sigmoid sinus
what is the hypoglossal canal below and medial to
jugular foramen
what is above the jugular foramen and what does this structure do
internal auditory meatus
passage for vestibular, cochlear and internal facial nerves
what is the hypoglossal canals realtionship in relation to the jugualr foramen
below and medial
what structure does the carotid canal end at
the foramen lacerum
what is the orbital cavity protected by
thick orbital margin
opening for nose leads to what structures and what are the 2 components separated by
leads to left and right nasal cavities separated by the nasal septum
the temporal fossa is enclosed by what 3 structures
ridge of temporal line
lateral orbital margin
zygomatic arch
what are the lateral and medial pterygoid plates and what direction are they oriented
thin sheets of bone that descend downwards
what 2 things does the hard palate form
roof of mouth and floor of nasal cavities
what are the 2 bony landmarks/structures that form the 2 big steps in the floor of the cranium
sphenoid ridges
petrous temporal bones
what borders make up the anterior cranial fossa
between front of skull and sphenoid ridges
what borders make up the middle cranial fossa
between sphenoid ridges and petrous temporal bones
what borders make up the posterior cranial fossa
between petrous temporal bones and back of skull
in the anterior cranial fossa, what do the bulges on either side of the cranium floor make up
roof of each orbit of the eye
what fossa is the crista galli a part of
middle of the anterior fossa
what is the crista galli
bony ridge of the ethmoid bone in the anterior cranial fossa
what is the structures immediately either side of the crista galli called and what is a key feature of them
what is the function of its key feature
cribriform plates
perforated bone which allows filaments of the olfactory nerve to pass through
what forms the roof of the nasal cavity
cribriform plates
what is the flat area behind the cribriform plate
roof of sphenoid sinus
what do the side wall and floor of the middle cranial fossa form (forms 2 structures)
wall of temporal fossa and part of orbit
what aspect of the orbit does the side wall and floor of the middle cranial fossa form
posterior part of the lateral orbital wall
what is the raised bump in the middle of the middle cranial fossa
sella turcica which is a deep depression for the pituitary gland
what are the shallow grooves around the sella turcica for and what are the 4 projections associated with this area
shallow grooves for 2 optical nerves
2 anterior and 2 posterior clinoid processes
what is the sloping area behind the posterior clinoid process and what is it continuous with
dorsum sellae
continuous with the base of the occiput
what does the lower part of the frontal bone form
3 structures
roof of nose
small part of temporal fossa
large part of roof of orbit
what does the frontal bone form in terms of the fossas
floor of the anterior cranial fossa
what is a feature of the frontal bone near the midline and what is this called
frontal bone near midline is hollow as it is the frontal sinuses
what 3 things does the zygomatic bone form/contribute to
cheek
lower lateral orbital margin
lateral orbital wall
where does the zygomatic bone form the zygomatic arch and what other structure contributes to the arch
extends back to meet the zygomatic processes of the temporal bone to form the arch
what parts is the maxilla bone made up of and what does it bear
right and left part
bears top teeth
what 3 structures does maxilla form/contribute to
lower and medial orbital margin
floor of orbits
what is a feature of the maxilla bone and why is this
hollow as it contains the maxilla sinus
what is the largest paranasal sinus
maxilla sinus
what 2 structures does the sphenoid bone form/contribute to
floor of the cranium and parts of the orbit
what are the 3 major projections of the sphenoid bone
lesser/greater wings
pterygoid process
what is the central part of the sphenoid bone made up of (2 structures)
clinoid processes and pituitary fossa
what is the highest part of the sphenoid
lesser wing
what structure does the lesser wing form
sphenoid ridge
what part of the sphenoid bone forms the back part of the orbit
underside of the lesser wing
what 2 structures does the greater wing of the sphenoid bone form/contribute to
front wall
a bit of the floor of the middle cranial fossa
where is the greater wing of the sphenoid joined to the lesser wing
superior/posterior aspect of the orbit
what separates the greater and lesser wings of the sphenoid bone medially
superior orbital fissure
what does the superior orbital fissure form
opening between orbits and inside of cranium
where does the pterygoid process project relative to the maxilla
downwards and behind maxilla
what are the only 3 parts of the ethmoid bone that can be seem externally
2 cribriform plates and in medial wall of each orbit
what do the lacrimal bones form
most medial part of inferior orbital margin
what does the nasolacrimal duct do
take tears from corner of eye to nasal cavity
what 2 structures does the palatine bone form on each sie
posterior parts of the hard palate
part of the side wall of nasal cavity
how many openings are there in the base of the cranium
of these how many pass forwards and how many pass downwards and how many pass obliquely
3 pass forward
2 pass downwards
one passes backwards obliquely
6 total
what is the round opening infront of the anterior clinoid process
optic canal
what does the optic canal transmit
optic nerve
what is the superior orbital fissure
what does it do
triangular passage in the orbit where nerves and blood vessels pass through to the orbit
what foramen is below and behind medial end of superior orbital fissure
foramen rotundum
what is the foramen rotundum for
maxillary branch of trigeminal nerve
where does the foramen rotundum emerge into
into terga maxillary fissure
not orbit
what is the relationship between the location of the optic canal and the clinoid processes
canal is just in front of anterior clinoid processes
what is the relationship between the location of the foramen rotundum and the superior orbital fissure
f rot is below and behind medial end of fissure
what are the 3 openings that pass forwards in the base of the cranium
optic canal
foramen rotundum
superior orbital fissure
what are the 2 openings that pass downwards in the base of the cranium
foramen ovale and spinosum
what is the foramen ovale for
mandibular branch for the trigeminal nerve
where is the foramen ovale on the external skull
just behind the pteragoid plate
where is the foramen spinosum located relative to the foramen ovale
behind and lateral to ovale
what is the foramen spinosum for
middle meningeal artery
externally on the skull what is the f spinosums position relation to the f ovale
same as internally, behind and lateral to ovale
what is the opening that passes laterally in the base of the cranium
foramen lacerum
what is the foramen lacerum for
internal carotid artery
how does the internal carotid artery run in the f lacerum relative to the carotid canal
f. lacerum is a opening through which the internal carotid artery emerges from its obliquely running carotid canal
where does the foramen lacerum emerge internally
tip of the petrous bone
what is the relation between the postiion of the end of the carotid canal to the styloid process
medial to styloid process
what is infront of the carotid canal
auditory tube
the auditory tube passes in which directions to emerge in the middle ear
backwards and laterally
the bony opening of the nose is called ___ ___ and tis leads to what structures separated by what
piriform aperture leading into left and right cavities separated by the nasal septum
the roof the nasal cavities is formed by what and what is a feature of this
cribriform plates
are very narrow
at the top of the nasal cavity what are the superior and side borders and inferior borders
ie what bones make up those borders
superiorly = floor of anterior fossa sides = medial walls of orbit and the hard plate inferiorly = hard plate
what are the 3 bony projections on the nasal cavity wall called
which wall of the nasal cavity are they located on
conchae/turbinate bones
lateral wall
what are the names of the 3 turbinate bones
which of them is the smallest
inferior, middle and superior (smallest) conchae
what parts make up the frontal sinus
left and right part
where does the frontal sinus extend to in the upwards and backward direction
upwards behind lower part of forehead
backwards between roof of orbit and floor of anterior cranial fossa
what parts make up the maxillary sinus
left and right parts
what parts make up the sphenoid sinus
left and right parts
where does the maxillary sinus extend to in the downwards and backward direction
backwards to part of maxilla that borders pteygomaxillary fissure
downwards to upper molar and premolar teeth
what is the maxillary sinus’s medial wall in the nasal cavity
lateral wall of nasal cavity
the maxillary sinus’s roof forms what part of the orbit
large part of floor of the orbits
where is the sphenoid sinus located
central part of sphenoid bone
above the sphenoid sinus floor is the ___ and ___, behidn it is the _____ and in front of it is the ____. Below it is the ____
above = floor of anterior cranial fossa & sella turcica
behind = basilar part of occipital bone
in front = high part of nasal cavity
below = roof of nasopharynx
where does the ethmoid bone extend from and along
from behind nasolacrimal duct to along medial wall of orbit
the middle part of the ethmoid bone going down vertically forms a large part of what structure
nasal septum
the tip of the middle vertical bone of the ethmoid bone is the beginning of what structure
beginning of the crista galli
each side of the crista galli are what structures
cribriform plates
the most lateral part of the ethmoid bone are what structures
lateral = lamina papyracea
what does the lamina papyracea form
most medial part of the orbit
which of the 3 conchae are part of the ethmoid bone
superior and middle
between what structures are the ethmoid air cells
lamina papyracea and upper part of nasal cavity
the ethmoid bone is joined to which bones above, below and behind
above = frontal below = maxilla behind = central part of sphenoid bone
