B1 - skull: protection of the CNS 2 Flashcards
what bones contribute to the neurocranium?
—> 8 : 4 unpaired and 4 paired
- temporal = paired
- parietal = paired
- occipital = unpaired
- frontal = unpaired
- ethmoid = unpaired
- sphenoid = unpaired
mnemonic to remember bones of neurocranium?
STEP OF
identify A-F
A = temporal
B = parietal
C = occipital
D = frontal
E = ethmoid
F = sphenoid
what does the frontal bone laterally articulate with?
zygoma
what bones contribute to the viscerocranium?
—> 14 bones: 6 paired and 2 unpaired
- maxilla = paired
- mandible = unpaired
- vomer = unpaired
- inferior nasal concha = paired
- lacrimal = paired
- nasal = paired
- zygomatic = paired
identify A-G
a = mandible
b = maxilla
c = vomer
d = inferior nasal concha
e = lacrimal
f = nasal
g = zygomatic
identify A-F and state whether they’re viscerocranial or neurocranial
A = maxilla - viscerocranial
B = palatine - viscerocranial
C = sphenoid - neurocranial
D = zygomatic - viscerocranial
E = temporal - neurocranial
F = occipital - neurocranial
describe the frontal bone
- creates a smooth curvature of the forehead
- protects the frontal lobe of the brain
- most anterior bone of the neurocranium
name A-F of the frontal bone
A = glabella
B = supraorbital notch
C = supraciliary ridge
D = frontal eminence
E = zygomatic process of frontal bone
F = nasal process of frontal bone
describe the sphenoid bone (what is it surrounded by anteriorly, superiorly, posteriorly and laterally?)
- surrounded anteriorly by the frontal bone, superiorly by the parietal bone and posteriorly, as well as laterally, by the temporal bone
- has a central part with 3 main projections = lesser and greater wings, pterygoid process
identify A-F of the sphenoid bone
A = greater wing
B = lesser wing
C = sella turcica
D = sphenoid sinus (in body)
E = lateral pterygoid plate
F = medial pterygoid plate
describe the lesser wing of the sphenoid bone
- highest part of sphenoid bone
- forms the sphenoid ridge
what does the sphenoid ridge do?
separates the anterior and middle cranial fossae
describe the ethmoid bone
- consists of a horizontal and vertical plate
- it cascades dow from the roof of the nasal cavity and separates it into 2 nasal passages
- its appendages include the superior and middle nasal conchae
identify A-F of the ethmoid bone
A = crista galli
B = perpendicular plate
C = cribiform plate
D = superior nasal concha
E = inferior nasal concha
F = ethmoid air cells
describe the occipital bone
- an unpaired bone
- the most posterior superior bone of the neruocranium
- creates the rounded bulb of the head at the nape of the neck and covers the cerebellum and the brainstem in a bony capsule
- the only cranial bone to articulate with the cervical spine
identify A-G of the occipital bone
A = foramen magnum
B = basiocciput
C = pharyngeal tubercle
D = occipital condyle (on each side of FM)
E = external occipital protuberance
F = superior nuchal line
G = external occipital crest
what joins to the occipital condyles of the occipital bone?
the atlas vertebrae
what passes through the foramen magnum?
the spinal cord + accompanying structures
what is the basilar part of the occipital bone? what converge on it on each side?
= the part in front of the foramen magnum
- slopes forwards and upwards
- temporal bones converge on it on each side
what is the squamous part of the occipital bone?
the part behind the foramen magnum
identify A-G of the temporal bone
A = squamous part
B = zygomatic process
C = petrous part
D = mastoid process (can feel behind ear)
E = mandibular fossa
F = external acoustic/auditory meatus
G = internal acoustic/auditory meatus
identify A-H of the mandible and what is the arrow pointing to?
A = coronoid process
B = angle
C = condyle/head
D = ramus
E = body
F = alveolar process
G = mylohyoid line
H = mandibular notch
arrow = mandibular foramen
identify A-G of the maxilla
A = frontal process
B = zygomatic process
C = orbital surface
D = alveolar process
E = maxillary tuberosity
F = anterior nasal spine
G = inferior orbital foramen
what separates the anterior and middle cranial fossa and the middle and posterior?
sphenoid ridges — anterior and middle
petrous temporal bones — middle and posterior
in what lobes do the cranial fossa sit?
anterior = frontal
middle = temporal
posterior = cerebellum
what does each cranial fossa contain?
- anterior — frontal lobe
- middle — temporal lobe and pituitary gland
- posterior — brainstem and cerebellum
what articulates to form the zygomatic arch?
temporal process of the zygomatic bone and the zygomatic process of the temporal bone
what articulates to form the temporal mandibular joint?
the head of the mandible with the mandibular fossa and articular eminence of the temporal bone
what are sutures and when do they fuse completely?
- a type of fibrous joint
- unique to skull
- immovable
- 20yo
- important in the context of trauma as they represent points of potential weakness
what are fontanelles?
membranous gaps in neonates between the bones due to i completely fused suture joints
what sutures are there in the skull?
what is the temporal fossa and what is it enclosed by?
= a shallow depression on the temporal region of the skull
enclosed by:
- temporal line
- lateral orbital margin
- zygomatic arch
what is the infratemporal fossa?
= an irregular space at the lateral aspect of the skull
- just inferior to the temporal fossa and deep to the ramus of the mandible
what is the pterygopalatine fossa?
= an inverted pyramidal-shaped,fat-filled space located on the lateral side of the skull, between the infratemporal fossa and the nasopharynx
- it is a major neurovascular crossroad between the orbit, the nasal cavity, the nasopharynx, the oral cavity, the infratemporal fossa and the cranial fossa
- can act as a natural conduit for the spread of inflammatory and neoplastic diseases in the head and neck
label this
