skull and foramina Flashcards
find a diagram and locate all skill and facial anatomy
what are the 6 cranial bones
- frontal
- parietal
- occipital
- temporal
- sphenois
- ethmoid
what are the 5 facial bones
- lacrimal
- nasal
- maxillary
- zygomatic
- mandible
what 2 cranial bones does the coronal suture seperate
frontal and parietal
what bone does the saggital suture seperate
the left and right parietal bone
what skull bones do the lambdoid suture seperate
parietal and occipital bone
what bones does the occipital mastoid suture seperate
occipital and mastoid part of temporal bone
what bones does the squamous suture seperate
- temporal and parietal
(squamous part of temporal bone from parietal)
what do you call the junction where the coronal and sagittal suture meet
bregma (top of head)
what do you call the junction where the lambdoid and sagittal suture meets
lambda
what do you call the junction where the frontal, parietal, temporal and sphenoid bone meet
pterion
what part of the skull is the weakest part
pterion junction
what structure lays beneath the pterion junction
- anterior division of the middle meningeal artery
a blow to the pterion junction can cause a middle meningeal artery rupture
what is a fontanelle
spaces between the bones of the skull where bone formation isn’t complete in foetus
what are the 4 fontanelles of foetuses
- anterior
- posterior
- sphenoid
- mastoid
what what ages do the different fontanelles fuse
anterior = 1-2 yrs old
posterior = 2-3 months
sphenoid = 6 months
mastoid = 6-18 months
what suture do infants have that adults dont
metopic
what does it mean if you see a depressed anterior fontanelle in a baby
- dehydrated, malnutrition
what does it mean if u see a bulging anterior fontanelle
- raised intracranial pressure e.g meningitis
the fontanelles can be used as ‘windows’ to undertake ultrasound assessment of underlying brain
cranial ultrasound cant be done one fontanelle have fused as US waves cannot penetrate through bone
by what age should the metopic suture in babies be closed by
9 months
keep in mind that metopic suture may persist (only in 3%) and be mistaken for a frontal lobe fracture or frontal sinus agenesis/ hypoplasia
what is hypoplasia
the incomplete development or underdevelopment of an organ or tissue
what is frontal sinus agenesis
The absence of a frontal sinus makes the skull more heavy and increases the sense of frontal headache
what can premature closure of the metopic suture (craniosynostosis) result in and what is this
trigonocephaly
- triangular apperance of the frontal skull
besides the pterion junction, where is another weak part in the skull
- cribriform plate (located in the anterior cranial fossa)
what are the 2 foramina found in the anterior crania fossa
- cribriform plate
- optical canal
what are the 4 foramen found in the middle cranial fossa
- foramen rotundum
- fortamen ovale
- foramen spinosum
- foramen lacerum
what are the 4 foramen found in the posterior cranial fossa
- internal acoustic meatus
- foramen magnum
- jugular foramen
- hypoglossal canal
what are the 4 bones that form the roof and floor of the nasal canal
nasal
ethmoid
maxilla
palatine
what 2 tissue structures are found in the nasal canal
nasal septum
nasal turbinates
what are the 4 bones and singular cartilage that make up the nasal septum
- perpendicular plate of ethmoid
- septal cartilage
- vomer
- maxilla
- palatine bone
what are the 4 sinuses found in the face
frontal
ethmoid
sphenois
maxilla
give some reasons for the function of the paranasal sinuses
- humifidying/heating air
- resonance to noise
- providing maximal strength for minimal material
- reduction of skull weight
- increasing facial dimension for origin of cranial muscle
- evolutionary remnants
which sinus would not be visible for an AP xray of the face
sphenoidal sinus
note that sinuses are very small at birth so you will not be able to see them in xray of newborn
when you look at paranasal sinuses, what is the first thing you investigate
symmetry of the sinueses
what is sinusitis
inflamed sinuses
what does sinusitis look like on CT and why
grey area as a result of excess mucus or swelling of tissue linings
- swelling can cause obstruction of passage to nasal cavity thus favouring infection to grow
what is the uncinate processes
thing bone/ hook on the medial wall of the maxillary sinuses just below the connection with the nasal cavity
how can the variation in the length of the uncinate process cause pathology
if the uncinate process is very long, the passage from the maxillary sinuses to middle meatus is narrow and might get more easily obstructed , mucus can cause inflammation
