Chapter 11 Notes - Cranium, Facial Bones, and Sinuses Flashcards
what bone is rests on the superior end of the vertebral column?
skull
what are the 2 main sets of bone of the skull?
- 8 cranial bones
- 14 facial bones
what are the cranial bones broken up to?
calvarium (skullcap) and floor
what are the bones in the skullcap?
- frontal
- right parietal
- left parietal
- occipital
what are the bones in the floor?
- right temporal
- left temporal
- sphenoid
- ethmoid
what is the frontal bone?
the bone that makes up the forehead and the superior part of each orbit
what are the 2 main parts of the frontal bone?
forehead - squamous/vertical portion
superior orbit - orbital/horizontal portion
define glabella
smooth/raised prominence between the eyebrows just above the bridge of the nose
define supraorbital groove (SOG)
slight depression above each eyebrow
define supraorbital margin (SOM)
superior rim of each orbit
define supraorbital notch
- foramen
- small hole or opening, slightly medial to the SOM
- supraorbital nerves and arteries pass through
define frontal tuberosity
- eminence
- large/rounded prominence superior to the SOG
what 4 bones does the frontal bone articulate with?
- right/left parietal
- sphenoid
- ethmoid
what bone forms the lateral walls of the cranium and part of the roof?
two parietal bones
define parietal tubercles (eminence)
widest portion of the entire skull
what 5 bones does the parietal bone articulate with?
- frontal
- occipital
- temporal
- sphenoid
- opposite parietal bones
define occipital bone
inferoposterior portion of the calvarium/skullcap
define squamous portion
- round
- forms most of the back of the head
- superior to the external occipital protuberance/inion
define the foramen magnum
- large opening at the base of the occipital bone
- spinal cord passes as it leaves the brain
- “great hole”
what condyles of the skull articulate with C1 atlas?
condylar portions/occipital condyles
what type of joint is formed between the occipital condyles and C1?
atlantooccipital joint
what 6 bones does the occipital bones articulate with?
- 2 parietals
- 2 temporals
- sphenoid
- C1/atlas
define temporal bones?
- left and right
- protect the delicate organs of hearing and balance
what are the three primary parts that break down the temporal bone?
- squamous portion
- mastoid portion
- petrous portion/petrous pyramid/pars petrosa
which part of the skull is the most vulnerable to fractures?
squamous portion
define petrous portion
houses the organs of hearing and equilibrium, including mastoid air cells
what portion of the temporal bone is the thickest and densest bone in the cranium?
petrous portion
define internal acoustic meatus
opening or orifice that transmit the nerves of hearing and equilibrium
what 3 bones does the temporal bone articulate with?
- parietal
- occipital
- sphenoid
what bone is centrally located in the skull and anchors the other seven cranial bones?
sphenoid bone
define sella turcica
- central depression of the body
- surrounds/protects the pituitary gland
define superior orbital fissures
openings providing additional communication with the orbits for numerous cranial nerves and blood vessels
what examinations can be done to visualize a deformity int he sella turcica?
CT and MRI
what are the 8 cranial bones?
- frontal
- right parietal
- left parietal
- occipital
- right temporal
- left temporal
- sphenoid
- eithmoid
define cribriform plate
portion of the bone containing several small openings/foramina where segmental branches of the olfactory nerves pass
where is the ethmoid located?
beneath the floor of the cranium
what bones does the ethmoid bone articulate with?
- frontal
- sphenoid
- 11 facial bones
define vomer
midline structure between parts of the sphenoid and parts of the ethmoid
define sutures
articulations/joints of the cranium
what is the classification of the stures?
fibrous joints
what type of mobility are the sutures of an adult cranium?
- synarthrodial-type joints
- immovable
list the 4 sutures in the cranium
- coronal suture
- sagittal suture
- lambdoidal suture
- squamous suture
define bregma
anterior end of the sagittal suture
define lambda
posterior end of the sagittal suture
define pterions
points at the junction of the frontal, parietals, temporals, and greater wings of the sphenoid
define asterions
points posterior to the ear where the squamosal and lambdoidal sutures meet
define fontanels
- space between the bones of the skull in an infant/fetus, where ossification is not complete
- sutures are not fully formed
define anterior/posterior fontanels
- bregma and lambda in infants
- ## “soft spots”
which fontanel is the largest at birth?
anterior fontanel
when does the anterior fontanel close during infancy?
18 months
what are the 6 fontanels in an infant?
- anterior fontanel
- posterior fontanel
- right sphenoid fontanel
- left sphenoid fontanel
- right mastoid fontanel
- left mastoid fontanel
define sutural/wormian
small/irregular bones
what structure is found in the petrous portion and temporal bone?
organs of hearing and equillibrium
what are the 3 divisions of the ear?
- external
- middle
- internal
what structures belong to the external ear?
- auricle
- pinna
- tragus
define (EAM) External acoustic meatus
opening or canal of the external ear
define middle ear
irregular shaped, air containing cavity
what structures make up the middle ear?
- tympanic membrane
- auditory ossicles
- tympanic cavity
define eustachian tube
passageway between the middle ear and the nasopharynx
what is the function of the eustachian tube?
serves to equalize the pressure within the middle ear to the outside atmospheric air pressure through the nasopharynx
what structures make up the internal ear?
internal acoustic meatus
what is a second direct communication in the middle ear?
mastoid air cells
what connects to the mastoid air cells?
antrum
what is the function of the auditory ossicles?
- permit vibratory motion
- transmit sound vibrations from the tympanic membrane to the oval window of the internal ear
what are the three auditory ossicles?
- malleus
- incus
- stapes
which out of the 3 auditory ossicles is the smallest bone?
stapes
what membrane leads to the inner ear?
oval window
how does sense of hearing occur?
when the longer root of the incus connects to the stapes, which connects to the oval window of the cochlea
what are the 3 parts of the osseous/bony labyrinth
- cochlea
- vestibule
- semicircle canals
what is the function of the semicircular canals?
sense of direction or equilibrium
what is the function of the cochlea?
sense of hearing
what are the 2 membranes of the internal ear?
- oval window/vestibule
- round window/cochlea
define oval window/vestibule
receives vibrations from the external ear (stapes), transmitting them to the vestibule
define round window/cochlear
membrane that allows the movement of fluid within the closed duct system
how does sense of hearing occur?
Vibrations and associated slight fluid movements within the cochlea produce impulses that are transmitted to the auditory nerve within the internal acoustic meatus
which 2 facial bones are unpaired?
vomer and mandible
which is the largest immovable facial bone?
(2) maxilla
what are the structures of the maxilla?
- body
- 4 processes
what are the 4 processes in the maxilla?
- palatine process
- frontal process
- zygomatic process
- alveolar process
define hard/bony palate
anterior portion of the roof of the mouth
define the zygoma
form the prominence of the cheeks and makeup the lower portion of the orbits
which bone is fractured due to a blow in the cheek?
zygomatic arch
which bones are the thinnest and most fragile?
lacrimal and nasal bones
define lacrimal bone
small/delicate bones that lie very close to the tear ducts
define nasal bone
- form the bridge of the nose
- the rest of the nose is made up of cartilage
define nasal conchae
- made up of three pairs
- divide nasal cavities into various compartments
- break up/mix the flow of the air before it reaches the lungs
what is the largest facial bone?
mandible
which bone is the only movable bone in the adult skeleton?
mandible
what classification is the temporomandibular joint?
synovial/diarthrodial
what is the movement type for the temporomandibular joint?
- bicondylar
- plane/gliding
what is the classification for alveoli and roots of teeth?
- fibrous/synarthrodial
- immovable
what is the subclass of the alveoli and roots of teeth?
gomphosis
define paranasal sinuses
- large, air filled cavities
- lined with mucous membranes