Skull Flashcards
what is the skull
bony skeleton- closed boc
houses brain, organs of special sense, upper parts or resp and gi systems
what kind of movement does the skull have
restricted, except tmj and atlanto-occipital joint
how many layers does the scalp have
5
Skin
Connective tissue
Aponeurosis
Loose areolar tissue
Periosteum
what is the function of the skull
protects brain, brainstem, cranial nerves, vasculature
muscle attachment
framework for head
individual identity
what kind of bones does the skull have
flat and irregular
pneumatised
what is the point of pneumatised bones and give examples
have air spaces
reduce weight and add resonance to voice
ethmoid, sphenoid, frontal, temporal
how do flat smooth bones form
by intramembranous ossification
how do irregular bones form
endochondral ossification
how many bones does the neurocranium have
8
frontal
parietal x2
occipital
sphenoid
temporal x2
ethmoid
how many bones does the viscerocranium have
15
ethmoid
palatine x2
zygomatic x2
maxilla x2
mandible
lacrimal x2
nasal x2
inferior nasal concha x2
vomer
3 single
what travels through the stylomastoid foramen
facial nerve
how many bones in he calvarium (skull cap)
4
fused by sutures
what is the superior sagittal sinus and what is found around it
superior sagittal sinus is a vein (carries venous blood) found in calvarium
originate from root of nose
on either side there are GRANULAR FOVEOLAE
arachnoid granulations, which absorb csf and pass into superior sagittal sinus to be drained
what are the parts of the L -shaped occipital bone
flat
squamous
irregular part
what do neck muscles attach to (occipital bone)
superior nuchal line
what is the midpoint of superior nuchal line
INION
what is the piriform aperture the entrance for
piriform aperture is entrance of nasal and oral cavity
where do branches of the trigeminal nerve CNV go through
opthalmic branch
maxillary branch
mandibular branch
supra-orbital notch
infra-orbital foramen
mental foramen
what is the pterygoid process
feet of sphenoid bone
with laminar- medial and lateral plate
what passes through the foramen magnum
spinal cord vertebral arteries
what forms jugular foramen
joint of temporal bones and occipital bone
2 jugular notches join together
what passes through jugular foramen
internal jugular vein
9,10,11 xn
what passes through hypoglossal canal
12th cranial nerve
what passes through carotid canal
internal carotid artery
what passes through foramen ovale
third division of trigeminal nerve
what passes through foramen spinosum
middle meningeal artery
what are fontanelles
gaps, sutures are not yet ossified
covered in skin and cartilage
ANTERIOR and PSTERIOR
found in infants
moulding of cranial shape during birth
allows brain to grow also makes vaginal delivery easier if big baby
what kind of join is a suture
fibrous joint
SYNARTHROSIS
limited/no movement
what does a bulge in the fontanelles mean
what does a depression in the fontanelles mean
is a pulsation normal?
- increased intracranial pressure
- dehydration
- yes it is due to the superior sagittal sinus
what are craniometric points
used by radiologists/surgeons as reference points
what is pterion
craniometric point
this area is weak (4 bones joined together)
if fracture can cause rapture of MIDDLE MENINGEAL ARTERY (branch of maxillary artery- pass through spinosum foramen) gives off branches just deep to pterion.
==EPIDURAL HAEMATOMA
what is the surface anatomy of pterion
4cm superior to midpoint of zygomatic arch
3cm posterior to frontal process of zygomatic bone
what forms the orbit
frontal
lacrimal
ethmoid
maxilla
zygomatic
sphenoid (greater wing)
palentine
what does the superior orbital fissure transmit
eyeball
lacrimal nerve
frontal nerve
superior ophthalmic vein
nasociliary nerve
oculomotor nerve
abducens nerve
trochlear nerve
last three are for eye muscles
what are the gateways of the orbit
superior orbital fissure
inferior orbital fissure
infraorbital foramen
optic foramen
allows structures to enter and exit orbit
connection between orbit and middle cranial fossa
what does the inferior orbital fissure transmit
zygomatic branch of maxillary nerve
infraorbital nerve
inferior ophthalmic vein
sympathetic nerve
connection between orbit and pterygopalatine fossa
what surrounds temporal fossa
superior and inferior temporal lines
discuss temporalis muscle
and masseter
temporalis muscle attaches to the inferior temporal line and attaches to coronoid process
(fascia attaches to superior line)
during contraction mandible is elevated and retracted
masseter on lateral side of angle of mandible
what are the boundaries of the infratemporal fossa
Laterally ramus of mandible
Medially lateral pterygoid plate of sphenoid bone
Anteriorly posterior aspect of maxilla
Posteriorly tympanic plate, mastoid and styloid process
Superiorly infratemporal crest of sphenoid bone
inferiorly angle of mandible
what does the infratemporal fossa communicate with
communicates with pterygopalatine fossa medially
where is the retromandibular fossa
discuss pterygopalatine fossa
inverted pyramid shape
connected to nasal cavity, orbit, pharynx, infratemporal fossa
what are the fissures found with pterygopalatine fossa
inferior orbital fissure
pterygomaxillary fissure
what are the foramina f the pterygopalatine fossa
spheno-palatine foramen
foramen rotundum
what are the canals of the pterygopalatine fossa
pharyngeal canal
vidian canal
pterygopalatine canal
what divides the cranial cavity fossa
anterior cranial fossa
sphenoid crest - lesser wing of sphenoid bone
middle cranial fossa
superior border of petrous temporal bone
posterior cranial fossa
what is crista galli part of
ethmoid bone
(beak of rooster)
cribiform foramina (holes) surrounf it
what is found in cribiform plate
olfactory nerve passes from nasal cavity into cranial fossa via cribiform plate
olfactory bulbs receive nerve fibres from nasal cavity via foramina of cribiform plate
how do cribriform plate fractures present
CSF rhinorrhoea
what does chiasmis mean
cross over
therefore some fibres of optic nerve cross over
what is the pituitary adenomas presentation
grow upwards, as no bone to sides or upwards towards optic chiasmatic sulcus
therefore present with visual disturbance
what is found in foramen spinosum
middle meningeal artery enters into cranial cavity
describe the posterior cranial fossa
brain stem esp. pons lies on, also cerebellum and occipital lobe
has 4 parts
what asses through hypoglossal canal
12th cranial nerve
what is the only moveable bone in skull
mandible
what does the masseter attach to
masseter attaches to lateral surface of ramus, process and angle of mandible
what does the temporalis muscle attach to
coronoid process of mandible
what passes through mandibular foramen
nerves for lower teeth enter here into mandibular canal
what is tmj
modified hinge joint
instead of flexion and extension (of usual hinge joint)- elevation and depression
articular disc separates into superior and inferior articular cavities
fibrocartilaginous disc
FIBROCARTILAGE, not hyaline cartilage
intrinsically unstable joint
glenoid fossa of temporal bone and condylar process of mandible
what is the most common type of dislocation at the tmj
ANTERIOR dislocation
large bite
or trauma when mouth is open
when depressed the condylar process moves anteriorly and lies under the articular eminences
mandibular head is vulnerable to anterior dislocation into the infratemporal fossa
describe the three ligaments of tmj
3 ligaments–1 intrinsic (lateral) strengthens joint
2 extrinsic ligaments- SPHENOMANDIBULAR (primary passive support) and STYLOMADIBULAR ligaments– allow swinging sideways
connect mandible to cranium
what are the movements of the mandible
elevation, depression- HINGE AND ROTATIONAL MOVEMENTS BETWEEN HEAD OF MANDIBLE AND ARTICULAR DISC (inferior cavity)
protrusion, retraction- GLIDING MOVEMENTS BETWEEN TEMPORAL BONE AND ARTICULAR DISC (superior cavity)
describe the first two cervical vertebrae (2/7)
first two are unique
ATLAS
no vertebral bodes, two lateral masses, two arches
articulate with occipital condyles and axis
AXIS
dens
what is typical vertebrae for cervical vertebrae
small vertebral body
triangular vertebral canal
transverse foramina
bifid spinous process
first to feel in neck is C7 (hence called vertebrae prominence)
what are the two joints found in the neck we are interested in
atlanto-occipital joint
1x median and 2x lateral atlanto-axial joints
what are the ligaments of the neck
alar ligaments
apical ligaments
with cruciform ligaments
keep dens in correct position
what happens if transverse (cruciform) ligament is ruptured?
bones will slide on each other and injure spinal cord
what is the anterior longitudinal ligament continuous with
atlanto occipital membrane
what is the posterior longitudinal ligament continuous with
tectorial membrane
discuss intervertebral joints
-intervertebral symphysis
secondary cartilaginous joint
hyaline cartilage on endplates
intervertebral disc-fibrous
supported by
-anterior longitudinal ligament
-posterior longitudinal ligament (pierced by vertebral artery, continues cranially as tectorial membrane)
discuss intervertebral joints
-facet (zygapophysial) joint
synovial joint
hyaline cartilage
between inferior and superior articular surfaces
supported by ligamentum flavum (runs between two adjacent laminae)
what to look at during cervial x ray
ADEQUACY- can you see all 7 c vertebrae and top of t1
ALIGNMENT- draw three parallel lines along anterior, posterior border of the 7 vert bodies, third though the base of each spinous process
ASYMMETRY- look for abnormal asymmetry between 7 cervical vertebrae
is the curve normal in cervical spine
yes- LORDOTIC curve 43 degree arc
absorbs shock
due to
-bone and disc shape
-muscle and ligament contributions
