skull osteology and fractures (A10) Flashcards
bones of the skull
- refer to images and checklists
- be able to describe in detail all of the 23 bones of the skull
alveolar bone
maxilla and mandible contain alveolar bone which holds the teeth
zygomatic arch
- cheek bone
- made up of: temporal process of zygomatic bone and zygomatic process of temporal bone
- easily fractured when punched
- as it forms part of the wall of orbit, fracture can cause bleeding and swelling of eye
superior and inferior nuchal lines (ridges on occipital bone)
muscle markings/ attachment sites
what structure passes through the foramen magnum
- spinal cord
- meninges (the three membranes-the dura mater, arachnoid, and pia mater, that line the skull and vertebral canal and enclose the brain and spinal cord)
sella turcica
depression where pituitary gland is situated (on pituatry fossa)
dural venous sinuses
endothelium-lined venous channels in the dura mater
neurocranium
- bones of the cranial vault (level above the orbits-below the ear divides neurocranium and viscerocranium)
- protects structures of brain
- areas further towards the back of the skull are stronger
viscerocranium
- bones of the face (level above the orbits-below the ear divides neurocranium and viscerocranium)
- holes within the facial bones decrease robustness
bones in area of vision (special sense)
bones within orbit
bones in area of hearing (special sense)
temporal bone (petrous)
bones in area of smell (special sense)
- nasal cavity:
- > lateral walls have conchae
- > upper and middle are ethmoid bone
- > inferior conchae is a separate bone
bones in area of taste (special sense)
- oral cavity:
- > mandible
- > maxilla
- > palatine
joints within the skull
- sutures between skull bones: coronal, sagittal, bregma, lamda, lambdoid
- temporo-mandibular joint (synovial)
radiographic markings on skull
-suture
-vascular marking
-fracture
-artifact? (artificial eg. nail scratch)
(refer to image)
->fracture looks darker on x-ray (tend to be hard straight lines)
middle meningeal artery
runs just deep to pterion (vulnerable at pterion)
types of fractures of the skull
- linear
- depressed
- comminuted
- basilar
buttresses of the cranium
-spread masticatory forces away from the relatively delicate orbit and nasal areas
le fort fractures
- 3 forms of maxillary fractures:
- le fort I (fractures at line of maxilla, seperates maxilla from rest of face, most important in dentistry as it runs across the level of the teeth)
- le fort II (fractures through orbits)
- le fort III (completely separates bones of neurocranium/cranial vault from bones of viscerocranium/facial bones at the level of the base of the skull)
- le fort III fracture causes bilateral peri-orbital haematomas(black eyes)
mandible
- coronoid process
- mandibular condyle (has a neck and head, also known as the condylar process of the mandible)
- ramus
- angle
- body
- mental protuberance
fractures of the mandible
-impacted wisdom tooth (gets stuck/lies between vertical and horizontal part of mandible) weakens the angle
cervical vertebrae
- C1-C7 bones (C1-C8 nerves, C1 nerve is above C1 bone)
- C1 articulates with the occipital condyles and C2
- C7 articulates with C6 and T1
atlas
- C1
- anterior and posterior arch
- no body
- facet for dens of C2
- superior articular facet for joining to occipital condyles
axis
- C2
- odontoid process (dens/peg)= body of C1
synovial pivot joint
- between C1 and C2
- shaking head/’no’ movement
cervical vertebrae structure (refer to image)
- bifid spinous process
- superior articular facet
- transverse process
- foramen transversarium
- body
foramen transversarium
passage way of vertebral arteries
vertebra prominens
- C7 (first vertebrae with prominent spinous process)
- first palpable spinous process
orbit
holds eye
nasal cavity
- protects special sense of smell
- airway
cranial cavity
hollow space inside the cranial vault that the brain is protected within
alimentary passage
entry for food and liquid
hearing and balance apparatus
within external auditory meatus
suture lines
fibrous joints
stonger bones of skull on anterior view
- frontal
- mandible
weaker bones of the skull on anterior view
- maxilla
- zygoma
- sphenoid
- nasal
external auditory meatus
hole through which sound waves travel
sphenoid bone
- single bone
- goes across base of the skull
- wedge shaped bone
- forms posterior part of orbit
pterion
- ‘H’ shaped suture
- thinnest part of the skull
- dangerous to fracture as middle meningeal artery runs across inside of skull and if torn can cause bleeding around the brain (middle meningeal artery has 2 branches)
squamous part of temporal bone
thin
sagittal suture
-divides parietal bones
coronal suture
- horizontal
- divides frontal bone from parietal bones
muscle markings on inside of mandible
attachment site of mylohyoid muscle
wormion bones
can get trapped within lamdoid suture?
lambdoid suture
divides occipital bone from parietal bones
mastoid process of temporal bone
muscle attachment of SCM
palate
made up of palatine process of maxilla and palatine bone
hard palate
formed when 2 maxilla meet in suture
condylar processes on base of skull/occipital condyles
- for attachment with vertebrae/C1
- kidney bean shaped structure lined in hyaline
medial and lateral pterygoid plates
for attachment of muscles?
cribiform plate of the ethmoid bone
- cribiform = a lot of holes
- transmits olfactory nerves (sense of smell)
- crista galli = ridge in the middle
orbital plate of the frontal bone
eyeball lies inferiorly
situation of pituitary gland
within pituitary fossa of sphenoid bone
location of organs of hearing and balance
temporal bones
cranial nerve location
attach with inferior surface of brain and pass through foraminae of skull (along with blood vessels) to enter/exit cranial cavity
maxillary air sinus
- within maxilla
- makes maxilla delicate
major bones of the orbit
- frontal bone(superior)
- sphenoid bone(posterior)
- zygoma(lateral)
- maxilla(inferior)
alveolar process of maxilla and mandible
- part that holds the teeth
- lots of air spaces within
temperomandibular joint
where the mandible articulates with temporal bone
mental process/protuberance of mandible
-bony part of chin
part of mandible most likely to fracture
- neck of mandibular condyle (thinnest part of mandible)
- >head of mandibular condyle swells as a result
joint responsible for nodding head
between occipital condyles and atlas
joint responsible for shaking head
- between atlas and axis
- synovial pivot joint
cervical vertebrae that DO NOT have bifid (fishes tail) spinous processes
-C1 and C7 (transition to thoracic vertebrae)
spaces on radiograph between cervical vertebrae
for intervertebral discs
odontoid process on radiograph of neck/cervical vertebrae
appears as shadow
