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60 terms

cranial floor, sinuses, the mandible and the fetal skull

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cranial floor
internal, bottom surface of the cranium
cranial fossae contains
ant. cranial fossa, post. cranial fossa, middle cranial fossa
ant. cranial fossa
formed by the orbital planes of the frontal bone and ethmoid bone
post. cranial fossa
large depression made up mostly of the occipital bone ; deepest and largest of the3 fossa
middle cranial fossa
loc. b/t ant. & post.cranial fossa
ethmoid bone contains
cribriform plate; crista gali
ethmoid bone is located
in the ant. fossa
cribriform plate
1) lies horozonally 2) its perforated 3) holes/ openings passageway for olafactory nervers from the nose to the brian
crista gali
upward projecting portions of bone from the midlline of the cribriform plate
optic foramina
1) pair of openings ant. to to the sella turcica 2) serves as an entrence/ exit to optic canal (3) optic nerve- passes thro these openings
chaismatic groove
narrow self extending from 1 optic foramina to the other
superior orbital fissure
(1) jagged opening loc. under ant. clinoid process (2) passageway for a set of cranial nerves and blood vessels
frontal bone contains
foramen cecum
frontal bone is loc
in the ant fossa
foramen cecum
small single opening ant to the ethmoid bone
sphnoid bone makes up
the middle fossa
sphnoid bone shaped like
a bat
sphnoid bone contains
smaller wing of sphenoid
smaller wing of sphenoid
the ant./lat points of the "bat wings"
hypophyseal fossa
(1) deep depression on the midline of the middle fossa (2) on post. portion of sphenoid bone (3) contain pituitary gland
dorsum sella
(1) directly post. to hypophyseal fossa (2) point project backwards
post. clinoid processes
the 2 outer pointy processes of the dorsum sella
sella turcica (turkish saddle)
consists of the above 4 structures
foramen rotundum
(1) arched opening post. of the sup. orbital fissure (2) passageway for a maxillary branch of cranial nerves ( trigeminal nerves)
temp. bone ( middle fossa) contains
squamous portion, petrous portion, mastoid part
squamous portion
thin portion that forms a part of the lat. surf of cranium
retrous portion
(a) hardest thickest portion of the cranium (b) internal acusticmeatus
internal acusticmeatus
loc on the medial surf of petrous portion internal opening of ear canal
mastoid part
(a) most post portion (b) loc. below petrous port (c) mastoid foramen (d) mastoid process
mastoid foramen
sm opening ant to the depression of the mastoid process
mastoid process
(fossa) on the internal surf. but a proc on the external surf appers as a depression
occipital bone contains
depression of the transversal sinus,
occipital bone facts
makes up the post fossa; appears as inf/sup nuchal lines on the external surf
paranasal sinuses
cavities which lighten the skull w/o weakening it; all of the sinuses have passageways leading to the nasal and oral cavities; there are 4 sets of paranasal sinuses
4 sets of paranasal sinuses
frontal sinuses ; maxillary sinuses ; sph. sinuses ; ethmoid sinuses/ air cells
frontal sinuses
loc above the eyes w/in the frontal bone
maxillary sinuses
largest sinuses , on each side of the nose and below the eyes; AKA antrums of highmore
sph. sinuses
most post of sinuses; loc w/in the sph bone; directly post to maxillary sinuses
ethmoid sinuses/ air cells
loc b/t frontal and sph. sinuses; appears as a group of small openings
the mandible
only movable bone of the skull; lower jaw bone; composed of two portions
two portions of mandibles
body- the single horizonal portion; ram/ ramous-the 2 vertical portions
symphysis (sdm)
point of fusion on the midline of the body of the mandible
incisive fossae (sdm)
2 small depressions on each side of the symphysis
mandibular condyle (sdm)
rounded process on the post/ sup portion of each ram; articulates w/the mandibular fossa on the temporal bone
coronoid processes (sdm)
pointed proc loc directly ant to mandubular condyle
mandibular notch (sdm)
the gap b/t the mandibular condyle and coronoid proc
angles (sdm)
the point where the body and the rami meet
oblique line (sdm)
a raised ridge of bone that extends from the rami down to the body on the external surf of the mandible
mylonyoid line (sdm)
a raised ridge of bone that extends from the rami down to the body on the internal surf of the mandible
alveolar process (sdm)
the raised portion of the mandible along the body that contains the teeth (gums)
mandibular foramina (sdm)
foramen loc on the internal surf of each rami
mental foramen (sdm)
foramen loc on the external surf of body; one on each side of the body
fetal skull
skull is not completley ossified at birth
fontanels
soft spots (a) un-ossified membranous areas of the fetal skull (b) undicated by a jagged line(c) eventually becomes a fused joint or suture
fontanels allow
allow the cranial bones to overlap during a normal vaginal delivery; ossification of a childs skull is complete around the age of 2; 6 total
the 6 fontanels
anterior fontanel; post fontanel; aterolateral; posterolateral
anterior fontanel
diamond shaped; most ant on the midline; at the junction of the frontal and parietal bones
post fontanel
diamond shaped but smaller than ant fontanel; lies on te midline at the junction of teh parietal and occipital bones
aterolateral fontanels
2 loc on each side of the skull; loc at the lat end of the coronalsuture
posterolateral fontanels
2 loc on each side of the skull; loc at the lat ends of the lamboidal suture