The Skull - Week 1 Flashcards
skull
cranium and mandible
cranium
no mandible
calotte
superior portion of the braincase
calvarium
calotte with cranial base but no face
neurocranium
top of the frontal bone to the lambdoidal suture
viscerocranium
- spanktocranium and facial skeleton
- facial features of the cranium
basicranium
base of the cranium that also contains the bones of the occipital
ectocranium
outside of the cranium
endocranium
inside of the cranium
how many bones in the skull are there?
28
how many bones of the skull are midline? how many are paired?
6 midline, 9 (22) paired
what are the midline bones of the skull?
- mandible
- frontal
- sphenoid
- occipital
- vomer
- ethmoid
what are the paired bones of the skull?
- parietals
- temporal
- zygomatic
- maxillae
- nasals
- lacrimals
- palatine
- inferior nasal conchae
- ear ossicles
what are the three ear ossicles?
malleus
incus
stapes
what are the key features of the frontal bone?
- frontal eminences/bosses
- horizontal portion
- zygomatic processes
- coronal suture
- temporal lines
- supraorbital margin - notch/foramen
- frontal sinuses
- ethmoidal notch
frontal crest - sagittal sulcus
- meningeal grooves
what are the key features of the parietals?
- sagittal, lambdoidal, and squamosal sutures
- temporal lines
- parietal boss
- parietal striae
- parietal foramen
- sagittal sulcus
- sigmoid sulcus
- meningeal grooves
what are the key features of the temporals?
- squamous portion
- zygomatic process
- mastoid process
- mastoid air cells
- styloid process
- petrous portion
- external auditory meatus
- internal auditory meatus
- cartoid canal
- glenoid fossa
- middle meningeal grooves
- squamosal suture
- parietal notch
- temporomandibular joint
key features of the occipital
- squamous portion
- external occipital protuberance
- nuchal lines
- lambdoidal suture
- basilar portion
- foramen magnum
- occipital condyles
- hypoglossal canal
- condylar canal
- cruciform eminence
- internal occipital protuberance
- sagittal sulcus
- transverse sulcus
- cerebral fossae (inferior and superior)
what are the key features of the sphenoid?
- center of the cranium
- wedge like with lots of articulations
- body: sinuses
- greater wing: foramen rotundum, foramen ovale, foramen spinosum
- lesser wing: optic canal, superior orbital fissure
- sella turcica: pituitary fossa, dorsum sellae, and clinoid processes
- pterygoid processes: lateral plate, medial plate
what are the key features of zygomatics?
- frontal process
- temporal process
- maxillary process
what are the key features of maxillae?
- alveolar process
- zygomatic process
- frontal process
- anterior lacrimal crest
- infraorbital foramen
- canine jugum
- canine fossa
- anterior nasal spine
- maxillary sinus
what are the key features of the palatines?
- horizontal plate - posterior nasal spine
- perpendicular plate
- pyramidal process and conchal crest
what are the key features of the ethmoid?
- cribriform plate
- perpendicular plate
- lateral masses - superior and middle nasal conchae
what bones make up the eye orbits?
frontal, sphenoid, zygomatic, maxilla, lacrimal, ethmoid, and palatine
what are the key features of the nasals?
nasal foramen
what are the key features of the vomer?
- perpendicular plate
- wings
what are the key features of the mandible?
- ramus - condyle and coronoid process
- corpus - alveolar process and alveoli
- gonial angle - masseteric tuberosity
- oblique line
- extramolar sulcus
- mental foramen
- mental eminence/protuberance
- mandibular foramen
- mylohyoid groove
- mylohyoid line - sublingual fossa and submandibular fossa
- mental spines - digastric fossae
what are the key features of the hyoid?
- body, lesser horn, and greater horn
endocranial cavity
the cranial fossae conform to the part of the brain and are influenced by attachments of dura mater
what are the parts of the brain?
cerebrum, cerebellum, and brainstem
what are the cerebral lobes?
frontal, parietal, temporal, and occipital
where are the frontal lobes located?
- anterior cranial fossa
where are the temporal lobes located?
middle cranial fossa
where is the cerebellum located?
posterior cranial fossa
where are the olfactory nerves located?
on the cribiform plate of the ethmoid
where are the pituitary and optic nerves
sella turcica
where is the brainstem located?
on the midline region of occipital (and sphenoid) called clivus
what are the components of bone?
- 20% water
- 35% organic (collagen)
- 45% inorganic (hydroxyapatite)
- bone is rigid and flexibility, lightweight support an strength
osteoblasts
- lay down new bone
- deposit organic matrix of bone (osteoid)
osteocytes
osteoblasts that have become trapped in osteoid
osteoclasts
- take away existing bone
- resorb bone mineral
primary osteon
- initial areas of ossification
- lamellar or woven bone
secondary osteon
- remodeling
- replaces bone on resorbed surfaces
what are the two types of bone development?
endochondral ossification and intramembranous ossification
endochondral ossification
- bone forms in a cartilage model
- characteristic of long bones, vertebrae and ribs
- uses hyaline cartilage as template for bone construction
- more complex than intramembranous ossification
intramembranous ossification
- bone forms within a membrane
- characteristic of cranial vault and facial bones
what is the endochondral bone formation process?
- a simple cartilage model of the long bone forms from hyaline cartilage
- osteoblasts lay down a bone (osteoid) collar around the shaft of the long bone
- blood vessels invade the presumptive bone, allowing entrance of osteoblasts, which lay down osteoid on mineralized cartilage matrix
- secondary ossification centers form at articulations and some muscles attachments
- epiphyseal disks allow growth of bone at junction of diaphysis and epiphyses
- fusion of epiphyses limits potential for increase in bone length
palmar
relating to the palm of the hand
plantar
relating to the sole of the foot
sphenooccipital synchondrosis
the joint between the basal portions of the sphenoid and occipital bones in that portion of the skull base usually designated as the clivus
glabella
the smooth part of the forehead above and between the eyebrows
