Cranium Flashcards
The skull is divided into two main sets of bones:
8 cranial bones and 14 facial bones
The 8 bones of the cranium are divided into:
the calvarium (skullcap) and the floor. Each consist of four bones.
The skullcap consists of which four bones?
Frontal, right parietal, left parietal and occipital
The floor of the cranium consists of which four bones?
Right temporal, left temporal, sphenoid, and ethmoid.
This bone contributes to the formation of the forehead and the superior part of each orbit:
Frontal bone.
The squamous portion of any the frontal bone is the ______ portion.
vertical.
The orbital portion of the skull is the ______ portion.
horizontal.
This is the smooth, raised prominence between the eyebrows just above the bridge of the nose:
Glabella.
This is the slight depression above each eyebrow:
The supraorbital groove (SOG).
Why is the supraorbital groove an important landmark?
It corresponds to the floor of the anterior fossa of the cranial vault, which is also at the level of the orbital plate or at the highest level of the facial bone mass.
The superior rim of each orbit is the :
supraorbital margin (SOM).
This is a small hole or opening within the SOM slightly medial to its midpoint:
Supraorbital notch (foramen.).
On each side of the squamous portion of the fontal bone above the SOG is a larger, rounded prominence termed the:
Frontal turberosity (eminence).
These form the superior part of each orbit:
Orbital plates.
Each orbital late is separated from the other by the:
ethmoidal notch.
The frontal bone articulates with which four cranial bones?
Right and left parietals, sphenoid, and ethmoid.
The lateral walls of the cranium and part of the roof are formed by two:
parietal bones.
The widest portion of the entire skull is located between the:
parietal tubercles (eminences) of the two parietal bones.
Each parietal bone articulates with these five cranial bones:
frontal, occipital, temporal, sphenoid, and opposite parietal.
The inferoposterior portion of the skullcap is formed by:
the single occipital bone.
The external surface of the occipital bone presents a rounded part called the:
squamous portion.
The squamous portion of the occipital bone forms most of the back of the head and is the part of the occipital bone that is superior to the:
external occipital protuberance, or inion.
The large opening at the base of the occipital bone through which the spinal cord passes is called the:
foramen magnum.
These oval processes with convex surfaces on each side of the foramen magnum are called the:
occipital condyles
The occipital bone articulates with these six bones:
Two parietals, two temporals, sphenoid and atlas.
The right and left temporal bones house what?
the delicate organs of hearing and balance.
Extending anteriorly from the squamous portion of the temporal bone is an arch of bone termed:
the zygomatic process.
____ and _____ have largely replaced conventional radiography for imaging of mastoids and petrous pyramids.
CT and MRI
The mastoids and petrous pyramids are locations for organs of:
hearing and equilibrium.
The three divisions of the ear are:
External
Middle
Internal
The parts of the external ear include:
The auricle, tragus, EAM, Mastoid process, mastoid tip, and styloid process.
The function of the tympanic membrane is to:
transmit sound vibrations.
The tympanic membrane is part of the:
middle ear
The three parts of the middle ear are:
Tympanic membrane, tympanic cavity, auditory ossicles
The partition between the external and middle ear is the:
tympanic membrane.
The space between the tympanic membrane and the bony labyrinth is called:
the tympanic cavity.
The tympanic cavity communicates with the nasopharynx by ________.
the eustachian tube.
The tympanic cavity is further divided into two parts:
tympanic cavity proper, which is opposite the eardrum, and epitympanic recess, which is the area above the level of the EAM and eardrum.
The bony projection to which the tympanic membrane is attached:
Drum crest. (separates EAM from epitympanic recess)
The passageway between the middle ear and the nasopharynx is:
the eustachian tube.
The eustachian tube equalizes pressure within:
the middle ear to the outside air.
The eustachian tube is a direct connection between:
the middle ear and nasopharynx, which allows disease organisms direct passage from throat to middle ear.
What is smaller in diameter than the EAM and difficult to demonstrate on conventional radiographs?
The internal acoustic meatus (IAM)
Another direct communication with the middle ear besides the eustachian tube is:
the mastoids.
The aditus is:
the opening between the epitympanic recess and the mastoid portion of the temporal bone.
The aditus, or the opening between the epitympanic recess and mastoid, allows infection in the middle ear, which may have originated in the throat, to pass to the:
mastoids. Infection is then separated from brain tissue by only thin bone.
Auditory ossicles transmit sound vibrations from:
tympanic membrane to sensory apparatus of hearing in the internal ear.
The auditory ossicles are named:
Malleus (hammer), Incus (anvil), Stapes (stirrup).
Describe how the auditory aussicles articulate between the tympanic membrane to the sensory apparatus of hearing in the internal ear:
The handle of the malleus is attached to the tympanic membrane and the head of the malleus articulates with the incus. The head of the stapes articulates with the incus and its base fits into the oval window of the inner ear.
The inner ear contains:
sensory apparatus of hearing and equilibrium within the densest portion of the petrous pyramids.
The inner ear is divided into two parts:
The osseous (bony) labyrinth and the membranous labyrinth.
The osseous labyrinth is a bony chamber that houses:
the membranous labyrinth.
The membranous labyrinth is a series of:
intercommunicating duts and sacs.
The osseous labyrinth is divided into three distinctly shaped parts:
the cochlea, the vestibule, and the semicircular canals.
The cochlea communicates with:
the middle ear through the round window.
The vestibule is the central portion of the osseous labyrinth that communicates with:
the middle ear by way of the oval window.
The semi-circular canals are located:
posterior to the other inner ear structures and are named according to their position (anterior, posterior and lateral.)
The cochlear and vestibular nerve pass through the IAM from:
respective parts of the membranous labyrinth to the brain.
The semi-circular canals relate to _______, and the cochlea relates to ________.
the sense of direction or equilibrium, the sense of hearing.
The oval window receives vibrations from:
the external ear through the stapes of the middle ear.
The oval window transmits vibrations to
vestibule of inner ear.
The round window is located at:
the base of the cochlear.
The round window allows movement of:
fluid within the closed duct system of the membranous labyrinth.
The oval window moves slightly _____ with a vibration.
inward
The round window moves _____ with a vibration.
outward
Vibrations and slight fluid movements within the cochlea produces:
impulses that are transmitted to the auditory nerve within the IAM, creating a sense of hearing.
SMV projection:
from inferior aspect of the mandible, in superior direction.
Long axis of orbit projects superiorly ___ degrees and projects medially ____ degrees.
30 and 37.
The base of the orbit is made of three bones:
The orbital plate of the frontal bone, and the zygoma and maxilla bones.
The orbits are composed of ___ cranial bones and ____ facial bones.
3 and 4
Which cranial bones help make up the orbits:
Ethmoid, frontal and sphenoid.
Which facial bones help make up the orbits?
Lacrimal, maxillary, palatine, and zygomatic.
Openings in the orbit include:
Optic foramen and superior orbital fissure separated by the sphenoid strut, and the inferior orbital fissure.
Which of the following facial bones is unpaired? Maxillary Palatine Lacrimal Vomer
Vomer
The anterior nasal spine is an aspect of the \_\_\_\_\_ bone. Maxillary Zygomatic Mandibular Inferior nasal conchae
Maxillary
The palatine process is an aspect of the \_\_\_\_\_ bone. Lacrimal Maxillary Palatine Zygomatic
Maxillary
Lacrimal is derived from a word meaning: Water Oil Tear Duct
Tear
Which facial bone forms an aspect of the bony nasal septum? Nasal Maxillary Ethmoid Vomer
Vomer
What is the name of the process of the mandible in which the lower teeth are embedded? Frontal process Alveolar process Body Mental symphysis
Alveolar process
The older term “antrum of Highmore” describes the:
maxillary sinuses
Which paranasal sinus is the last one to develop?
Ethmoid
The posterior aspect of the bony orbit is termed the:
Apex
Which of the following bones makes up most of the lateral wall of the orbit? Maxillary Lacrimal Zygomatic Vomer
Zygomatic
What passes through the optic foramen?
The optic nerve
Plain radiographs will show presence or absence of skull fractures but won’t indicate _______.
underlying brain injury. A CT/MRI is performed to assess brain tissue.
Linear fractures of the skull appear as:
jagged or irregular lucent lines that lie at right angles to the axis of the bone.
Depressed fractures of the skull looks like:
a fragment of bone is separated and depressed into the cranial cavity. Also called ping pong fractures.
What view may be used to determine the degree of depression of a depressed fracture if CT is not available?
Tangential.