the skull - occipital and temporal Flashcards
occipital bone
unpaired bone at rear of skull
what kind of ossification does the occipital bone undergo
intramembranous (squamosal portion) and endochondral (basilar and condylar portion)
three main divisions of occipital bone
squamosal, basilar, condylar
basioccipital/basilar portion
anterior to formen magnum
occipital condyles/condylar portion
lateral to foramen magnum (on either side)
articulate with vertebra
foramen magnum
separates basilar and condylar portions from squamous portion
where spinal cord leaves the skull
occipital plane
occipital squama located above superior nuchal lines
nuchal plane
neck plane located below nuchal lines
superior nuchal line
separates occipital and nuchal planes
located on either side of midline
attachment site for several nuchal (neck) muscles (e.g. trapezius)
inferior nuchal line
parallel superior nuchal line
site of attachment of fascia separating nuchal muscles
below inferior nuchal line, additional nuchal muscles attach here
external occipital protuberance
located along midline where occipital and nuchal planes intersect
very variable – more prominent in males than females
inion cranial landmark
intersection of superior nuchal lines on the external occipital protuberance
like a little hook
external occipital crest
attachment site of nuchal ligament
on sagittal plane from superior nuchal line to foramen magnum
condylar fossae
small depressions posterior to condyles
recieve posterior margin of superior articular facet of atlas during head extension (C1 vertebra = atlas)
condylar foramen
small foramen located in basin of condylar fossa
transmit emissary vein
jugular process
located lateral to the condyles
sticking out right next to the jugular foramen
articulates with temporal bone at occipitomastoid suture
jugular foramen
second largest foramen located in the condyles right next to the jugular process
jugular notch
where jugular foramen forms with the other bone
medial margin of jugular process
hypoglossal canal
anterior to condyles
transmits hypoglossal nerve (CN XII) and arteries
basioccipital
thick, square projection anterior to foramen magnum
basilar (sphenoccipital) synchondrosis (suture)
joint between basioccipital and sphenoid (fuses 18-25 years of age)
cruciform eminence
cross on the middle inside of occipital
divides endocranial surface of occipital squama into four parts