axial skeleton part 1 Flashcards
How many bones are in the axial skeleton?
80
What are the bones of the skull & face?
8 cranial, 14 facial, 6 auditory ossicles, and hyoid bone
What are the bones of the vertebral column?
24 vertebrae, sacrum, and coccyx
What are the bones of the thoracic cage?
sternum & 24 ribs
What do the cranial bones do?
enclose & protect the brain
What are the cranial bones?
they are 8 flat bones: occipital, frontal, sphenoid, ethmoid, parietal (paired), and temporal (paired)
What is the cranial cavity?
fluid-filled chamber that cushions and supports the brain
What do facial bones do?
protect & support the entrances to the digestive and respiratory tracts
What are sutures?
immovable joints between skull bones
What is the lambdoidal suture?
separates the occipital from the 2 parietal bones
What is the coronal suture?
separates the frontal from the parietal bones
What is the sagittal suture?
separates the 2 parietal bones and runs from the lambdoid to the coronal suture
What is the squamousal suture?
separates the temporal from the parietal bone on each side
What is the occipital bone?
forms the posterior & inferior surface of the cranium
What are the occipital condyles?
where the skull articulates with the 1st vertebrae
What are the inferior/superior nuchal lines?
ridges that are sites of muscle & ligament attachment that stabilize the head on the neck
What is the foramen magnum?
passage for the brain stem to connect to the spinal cord
What is the jugular foramen?
lies between the occipital & temporal bone; passage for internal jugular vein that carries venous blood from brain
What are the hypoglossal canals?
passage for cranial nerves that control the tongue
What are the parietal bones?
form part of the superior & lateral surfaces of cranium
What is the frontal bone?
forms anterior surface of cranium and the roof of the orbits (eye sockets)
What is the frontal squama?
“forehead”; provides attachment for muscles of face
What is the supra-orbital margin?
thickening of the frontal bone that helps protect the eye (eyebrows)
What is the supra-orbital foramen?
passage for blood vessels of the eyelids, eyebrows, and frontal sinuses
What are the temporal bones?
form part of lateral walls of zygomatic arches; form the only articulation with mandible; surround & protect organs of inner ear; attachment site for muscles that close jaw and move head
What is the zygomatic process?
where the temporal bone meets the zygomatic bone; helps form the zygomatic arch (cheekbone)
What is the mandibular fossa?
articulation with mandible
What is the mastoid process?
behind ear; attachment site for muscles that rotate or extend the head; has air cavities (mastoid sinuses)
What is the styloid process?
sharp, needle-like projection near the base of the mastoid process; attachment for ligaments that support the hyoid bone
What are the auditory ossicles?
located in the middle ear; 3 bones on each side that transfer sound vibrations from the tympanic membrane (eardrum) to the inner ear
What is the carotid canal?
passage for internal carotid artery (major artery to brain)
What is the foramen lacerum?
passage for auditory tube that connects the pharynx (throat) to the tympanic cavity
What is the external acoustic meatus?
on the lateral surface; canal that leads to the eardrum/middle ear
What is the stylomastoid foramen?
posterior to the base of the styloid process; passage for facial nerve
What is the internal acoustic meatus?
carries blood vessels & nerves to the inner ear
What is the sphenoid bone?
forms part of the floor of cranium; acts to brace & strengthen the sides of the skull; bat/butterfly shape
What is the sella turcica?
“Turk’s Saddle”; pituitary gland sits here
What are the lesser wings?
anterior to sella turcica
What are the greater wings?
forms part of the cranial floor and part of posterior wall of orbit
What is the optic canal?
passage for the optic nerves from eyes to brain
What is the foramen ovale?
oval shape; passage of nerve to chewing muscles
What are the foramen rotundum & foramen spinosum?
penetrate the greater wing; passages for blood vessels & nerves to the eye, face, and jaw
What is the superior orbital fissure?
slit-like opening; nerves controlling eye movements
What is the ethmoid bone?
forms the anteromedial floor of cranium, roof of the nasal cavity, part of the nasal septum, and medial walls of orbits
What is the cribriform plate?
forms anteromedial floor of cranium and roof of nasal cavity
What are the olfactory foramina?
in the cribriform plate; small holes for passage of olfactory nerves (sense of smell) from nose to brain
What is the crista galli?
bony ridge that protects superior to the cribriform plate; the membrane that stabilizes the position of the brain attaches here
What are the superior & middle nasal chonchae?
projections that break up airflow in nasal cavity to help get rid of foreign particles, warm the air, and aid in smell; form lateral walls of nasal cavity
What is the perpendicular plate?
forms part of the nasal septum
How many facial bones are there?
14; 12 paired + mandible & vomer
What is the maxilla?
2 bones; the upper jaw/upper lip; largest facial bone; supports upper teeth
What is the alveolar processes/margin?
supports upper teeth
What are the palatine processes?
form anterior part of the hard palate (roof of mouth)
What is cleft palate?
results when the maxillae fail to meet along the midline of the hard palate
What is the inferior orbital rim?
protects the eye
What is the infra-orbital foramen?
located just below the orbit; path for a major sensory nerve
What is the inferior orbital fissure?
between the maxilla and sphenoid; passage for cranial nerves and blood vessels
What are the palatine bones?
2 bones; posterior portion of the hard palate and part of the floor of each orbit
What are the nasal bones?
“bridge of nose”; small rectangular bones
What is the vomer bone?
forms interior portion of bony nasal septum
What are the inferior nasal chonchae?
thin, curved bones that project from the walls of the nasal cavity; create air turbulence and increase the surface area to promote warming & humidifying of air
What are the zygomatic bones?
“cheekbones”; form part of the rim & lateral wall of the orbits
What is the temporal process?
connects with the zygomatic process of the temporal bone to make the zygomatic arch
What are the lacrimal bones?
smallest facial bones; form the medial walls of the orbits; has groove & fossa for passageway for tears
What is the mandible?
“lower jaw”; largest/strongest facial bone that connects with temporal bone at the mandibular fossa; forms the only freely movable joint of skull
What is the body of the mandible?
horizontal portion
What is the alveolar process?
supports lower teeth
What is the mental protuberance?
“chin”
What is the ramus?
ascending part of mandible
What is the condylar process?
articulates with temporal bone at temporomandibular joint
What is the coronoid process?
insertion point for temporalis muscle (closes the jaw)
What is the mandibular notch?
depression that separates the condylar and coronoid processes
What are the mental foramina?
opening for sensory nerves of lips & chin
What is the mandibular foramen/canal?
passage for nerves/blood vessels of lower teeth
What is temporomandibular joint (TMJ) syndrome?
mandible is pulled slightly out of alignment causing muscle spasms & pain
What is the hyoid bone?
horse-shoe shaped; supports the larynx
What is the only bone in the body that does not articulate directly with any other bone?
the hyoid bone
What are characteristics of the hyoid bone?
attachment point for muscles that raise and lower the larynx when we swallow & speak; stylohyoid ligaments connect the lesser horns with styloid processes of temporal bones and create a “swing” for the larynx
What is the body of the hyoid bone?
muscles attach for larynx, pharynx, and tongue
What are the greater horns?
muscles attach for tongue movement
What is the orbital complex?
eye socket
What bone makes up the roof of the orbital complex?
frontal bone
What bone makes up most of the floor of the orbital complex?
maxilla
Which bones make up the medial wall & rim of the orbital complex?
maxilla, lacrimal, and ethmoid
Which bones make up the lateral wall & rim of the orbital complex?
zygomatic, sphenoid, and maxilla
What is the nasal complex/cavity?
encloses the nasal cavities & paranasal sinuses
Which bones make up the superior wall of the nasal complex?
frontal, sphenoid, and ethmoid
Which bones make up the lateral walls of the nasal complex?
maxilla, lacrimal, and ethmoid (nasal chonchae)
Which bones make up the bridge of nose of the nasal complex?
maxilla & nasal bones
What are the paranasal sinuses?
air-filled chambers that surround nasal cavity & drain into the nasal passages
What are characteristics of the paranasal sinuses?
make bone much lighter, lined with mucus that moistens & cleans the air
What is sinusitis?
inflammation of the sinuses
Where is the frontal sinus?
just above eyebrows; flush nasal cavities
Where is the ethmoid sinus?
between eyes
Where is the sphenoid sinus?
lies posterior to ethmoid sinus; help clean nasal cavities
Where is the maxillary sinus?
side of nose just superior to maxilla; largest
What are features of the fetal & infant skull?
face is very small compared to the cranium, skull is large compared to the infant’s body length, 1/4 as long as the entire body (adults=1/8), at birth the skull is unfinished- areas of cartilage still not ossified
What are fontanelles?
fibrous tissue “soft spots” in skull of infants
What is the purpose of fontanelles?
allow for head to be distorted during birth, allow for brain growth- most significant growth occurs before age 5 at which point brain stops growing and the sutures develop, and they can’t be felt after 22-24 months of age
What is the anterior fontanel?
largest; top/front of head; babies pulse can be seen through this soft spot; stays until about age 2
Where is the occipital fontanel?
back of head
Where is the sphenoidal fontanelle?
near the temple
Where is the mastoid fontanelle?
behind the ear
When do the occipital, sphenoidal, and mastoid fontanelles disappear?
1-2 months after birth
What are the parts of the occipital bone?
occipital condyles, inferior/superior nuchal lines, foramen magnum, jugular foramen, & hypoglossal canals
What are the parts of the parietal bones?
none
What are the parts of the frontal bone?
frontal squama, supra-orbital margin, & supra-orbital foramen
What are the parts of the temporal bones?
zygomatic process, mandibular fossa, mastoid process, styloid process, auditory ossicles, carotid canal, foramen lacerum, external acoustic meatus, stylomastoid foramen, & internal acoustic meatus
What are the parts of the sphenoid bone?
sella turcica, lesser wings, greater wings, optic canal, foramen ovale, foramen rotundum, foramen spinosum, & superior orbital fissure
What are the parts of the ethmoid bone?
cribriform plate, crista galli, olfactory foramina, superior and middle nasal chonchae, & perpendicular plate
What are the parts of the maxillae?
alveolar processes/margin, palatine processes, inferior orbital rim, infra-orbital foramen, & inferior orbital fissure
What are the parts of the palatine bones?
none
What are the parts of the nasal bones?
none
What are the parts of the vomer bone?
none
What are the parts of the inferior nasal chonchae?
none
What are the parts of the zygomatic bones?
temporal process
What are the parts of the lacrimal bones?
lacrimal groove & lacrimal fossa
What are the parts of the mandible?
body, alveolar process, mental protuberance, ramus, condylar process, coronoid process, mandibular notch, mental foramina, & mandibular foramen/canal
What are the parts of the hyoid bone?
body & greater horns
