Bones of the Skull Flashcards
cranium is divided into
neurocranium and viscerocranium
neurocranium divided into ___ and _____. function
roof=calvaria/dome
base=floor of skull
serves as roof of head and protects brain
viscerocranium
facial part of head
suture
synarthroses (strong & immobile) connects all of the bones of the skull
coronal suture
ear to ear across the top of the skull
sagittal suture
runs along the midline of the skull separating parietal bones (front to back)
lambdoid suture
connects parietal bone to occipital bone (located at back of skull)
squamous suture
joins parietal bone to squamous part of temporal bone (located on side of skull)
when do the sutures become immobile?
after 2 y/o
fotanels
soft gaps between cranial bones present until 2 y/o
how many fotanels and order of closing?
6 fotanels
posterior closes 1st
sphenoid closes 2nd
mastoid closes 3rd
anterior closes 4th
“PSMA”
purpose of fotanels
allow baby to pass through birth canal and allow brain to continue growing
craniosynostosis
birth defect where baby’s skull bones fuse together prematurely limiting brain growth and abnormal skull growth (premature ossification of fotanels)
calvaria
top part of neurocranium
what are the bones that make up the calvaria?
frontal, 2 temporal, 2 parietal, and occipital
what are the 2 layers of the calvaria and what separates them?
inner thin layer and outer layer for protection.
separated by diploe
diploe
spongy bone tissue with bone marrow an diploic veins
frontal bone
Forms what 2 structures
forms forehead and superior rim of orbit
pneumatized bone
parietal bone
single/paired & shape
forms _ and __ of cranium
paired quadrilateral bone
forms roots and sides of cranium
occipital bone
has 4 parts
contains which main foramina that contains what main structure
has 4 parts: squamous, basilar, and 2 lateral parts
contains formane magnum where spinal cord passes through
temporal bone
Paired or single /shape
Houses ___
Comp of 4 parts ____
paired, flat bone
houses ears
pneumatized bone
composed of 4 parts: squamous, zygoatic process, tympanic membrane and styloid, and petromastoid
cranial base
floor of cranial cavity
has 2 surfaces: endocranium & external cranial base
components of cranial base
sphenoid, ethmoid, occipital, frontal, and temporal
viscerocranium
facial skeleton
all bones joined by synarthroses except mandible
ethmoid bone
separates nasal and cranial cavity
pneumatized
articulates with frontal and sphenoid bones
what is the superior projection of the ethmoid bone?
crista galli
what tunnel like structure are found on either side of the ethmoid bone?
cribiform plate
sphenoid bone
composed of what 4 parts
pneumatized
composed of: body, greater wing, lesser wing, and pterygoid process
what is the depression in the body of the sphenoid bone called and what does it contain?
sella turcica - houses pituitary gland
what nerve passes through the sphenoid bone?
the optic nerves pass through the optical canal of the sphenoid bone
zygomatic bone
Shape / paired/single?
Forms what 2 parts of orbit
irregular paired bone
forms part of orbit’s inferior and lateral rims
nasal bone
Forms what structure of nose
Articulates with which 2 structures
forms bridge of nose
paired
articulates with frontal bone and maxilla
maxilla
Describe structure
Composed of body & what 4 processes
large, paired bone
pneumatized
holds upper teeth
composed of: body and 4 processes
4 processes: zygomatic, alveolar, palatine, and frontal
palatine bone
forms hard palate with maxila
composed of 2 perpendicular plates:
horizontal plate = hard palate
vertical plate = lateral wall of nasal cavity
mandible
forms what 2 facial structures
paired/unpaired
articulates with ___ through ____ joint
3 parts
large bone forming chin and jaw line
unpaired
articulates with temporal bone through temporomandibular joint (TMJ)
holds lower teeth
composed of: ramous, body, and alveolar processes `
bones of skull are connected through synarthrosis. state each synarthrosis and what 2 bones it connects
squamosal suture- temporal and parietal (STP)
coronal suture - between frontal and parietal (CPF)
lambdoidal suture- between occipital and parietal (LOP)
sagittal suture- between the 2 parietal bones (SPP)
which bones exist singularly?
frontal
lacrimal
parietal
temporal
sphenoid
ethmoid
occipital
frontal, sphenoid, ethmoid, occipital
