Osteology of the Skull and Cervical Spine Flashcards
how many bones are in the skull?
23
what is the function of the skull
to house the brain, provide attachment for muscles, provide framework for the head
what are flat, smooth bones formed by?
intramembranous ossification
what are irregular bones formed by?
endochondral ossification
what are pneumatised bones?
bones with air spaces
how are flat and irregular bones distinguished?
by shape and embryological origin
what are the 2 divisions of the skull
neurocranium and viscerocranium
what is the neurocranium
bony case of the brain including cranial meninges
what is the viscerocranium
anterior part of cranium that consists of bones around oral cavity, nasal cavity and most of the orbit
what is the function of air spaces
to reduce weight and add resonance to the voice
how many bones are in the neurocranium and what are they?
8 bones, frontal, ethmoid, sphenoid, occipital, temporal, parietal
how many bones are in the viscerocranium, and what are they?
ethmoid, vomer, mandible, nasal, lacrimal, zygomatic, palatine, maxilla, inferior nasal conchae
what is the vertex?
superior point of neurocranium in the middle
what is the bregma
junction of sagittal and coronal suture
what is the lambda
junction of lambdoid and sagittal suture
what is the inion
most prominent point of external occipital protuberance
what is the asterion
star shaped junction of suture between occipital, parietal and temporal bones
what is the nasion
where frontonasal and internasal sutures meet
what is the glabella
smooth part of frontal bone superior to nose (most projected part of the forehead)
what is the pterion
H-shaped junction of sutures
what bones meet at the pterion
frontal, parietal, temporal and greater wing of sphenoid bone
why is the pterion clinically relevant?
it is structurally weak and vulnerable to injury
what are the small islands of bone within the lambdoid suture called?
sutural/accessory or wormian bones
what are sutures
type of fibrous joint
what are fontanelles
fibrous membranes
what is the periform aperture?
the interior nasal opening into the cranium
what are the paired sinuses
frontal, ethmoidal, maxillary
what does the spinal cord enter the skull through?
foramen magnum
what foramen does the middle meningeal artery go through
the foramen spinosum
where is the foramen spinosum?
in the sphenoid bone
how many vertebrae are in the cervical spine?
7
what do the cervical vertebrae allow
flexion and rotation
what are ligament nuchae?
ligaments which attach external occipital protuberance and foramen magnum to spinous process of the vertebrae
what do the ligament nuchae do?
support the head, resists flexion and is an attachment point for muscles
what are the parts of the typical vertebrae?
body, transverse process, spinous process, anterior and posterior tubercles, foramen transversarium
what are the parts of the atlas?
anterior arch, posterior arch,lateral mass, articular facet for dens, superior articular facet for occipital condyle
what is the part of the axis?
superior articular facet for the atlas, dens, transverse foramen, lateral mass
what does the atlas not have?
a body
what does the atlas provide
an articular surface for occipital condyle of skull
what are the joints involved in the vertebrae?
lateral atlanto-axial joint and pivot joint of dense, and atlanto-occipital joint
what does the lateral atlanto-axial joint allow?
rotation of head
what does the atlanto-occipital joint allow?
flexion and extension (nodding)
what do alar ligaments do?
prevent excessive rotation of the head and neck and connects the dens to occipital condyles
what is the hyoid bone?
U-shaped bone found at C3 level in anterior neck
what are the parts of the hyoid bone?
2 greater horns, body, 2 lesser horns
what do the 2 lesser horns of the hyoid bone attach to?
stylohyoid ligament
