403: Skull Osteology

How many bones make up the neurocranium?

8 bones

frontal (2)

parietal (2)

occipital

sphenoid

temporal (2)

ear ossicles (6)

How many bones make up the viscerocranium?

15 bones

ethmoid

maxilla [2]

palatine [2]

zygomatic (2)

nasal (2)

vomer

inferior nasal concha (2)

lacrimal (2)

mandible

How many adult skull bones are there?

29

identify the structure:

frontal bone (2)

identify the structure:

parietal bone (2)

identify the structure:

occipital bone

identify the structure:

ethmoid bone

Identify the bone

Ethmoid bone

identify the structure:

sphenoid bone

identify the structure:

maxilla (2)

identify the structure:

temporal bone (2)

identify the structure:

palatine bone (2)

identify the structure:

zygomatic bone (2)

identify the structure:

nasal bone (2)

identify the structure:

vomer

identify the structure:

inferior nasal concha (2)

identify the structure:

lacrimal bone (2)

identify the structure:

mandible

identify the structure:

ear ossicles (6)

identify the bones

ear ossicles

Identify the structure

External acoustic meatus

Identify the structure

Mastoid process

Identify the structure

Temporal process of maxilla

Identify the structure

Frontal process of maxilla

what 7 bones make up the orbit?

maxilla

zygomatic

frontal

sphenoid

ethmoid

lacrimal

palatine

Identify the structure at #1

Orbital plate (frontal bone)

Identify the structure at #2

Sphenoid lesser wing

Identify the structure at #3

Orbital plate (ethmoid bone)

Identify the structure at #4

Lacrimal bone

Identify the structure at #5

Sphenoid greater wing

Identify the structure at #6

Orbital plate (zygmoatic bone)

Identify the structure at #7

Orbital plate (maxilla)

identify the structure:

zygomaxillary suture

identify the structure:

nasomaxillary suture

identify the structure:

intermaxillary suture

identify the structure:

medial palatine suture

identify the structure:

transverse palatine suture

identify the structure:

palatine process of maxilla

identify the structure:

horizonal plate of palatine bone

identify the structure:

nasion suture

identify the structure:

internasal suture

identify the structure:

coronal suture

identify the structure:

sagittal suture

identify the structure:

bregma suture intersection

identify the structure:

lambdoid suture

identify the structure:

lambda suture intersection

identify the structure:

asterion suture intersection

identify the structure:

pterion suture intersection

what 4 bones articulate to make the pterion suture?

sphenoid (greater wing)

frontal

parietal

temporal (squamous part)

What bones articulate to make the asterion?

Occipital

Parietal

Temporal

What bones articulate to make the bregma?

Frontal

Parietal

what structure lay directly inferior to the pterion?

middle meningeal a.

A fracture at the pterion could cause a...

Epidural hematura

identify the structure:

anterior (frontal) fontanelle (7-19 months)

identify the structure:

posterior fontanelle (1-2 months)

identify the structure:

mastoid fontanelle (1-2 months)

identify the structure:

sphenoidal fontanelle (1-2 months)

which fontanelle becomes the pterion?

sphenoidal fontanelle

identify the structure:

persistent metopic suture

identify the structure:

Sutural (wormian) bones

Identify the pathology:

There is no pathology! These are normal wormian bones

What structures are derived postnatally?

1) Bony processes

2) Air spaces

name two bones that are non-existant and develop in a growing infant:

mastoid process

styloid process

what muscle attaches to the mastoid process?

sternocleidomastoid m.

What muscles and ligaments attach to the styloid process?

Stylohyoid m.

Stylopharyngeus m.

Styloglossus m.

Stylohyoid ligament

Stylomandibular ligament

identify the structure:

external occipital protuberance

identify the structure:

external occipital crest

identify the structure:

superior nuchal line

identify the structure:

inferior nuchal line

what structure attaches to the nuchal crest?

nuchal ligament

what 2 muscles attach to the superior nuchal line (top arrow)?

trapezius m.

occipitalis m.

identify the structure:

frontal sinus

identify the structure:

ethmoid sinus

identify the structure:

sphenoid sinus

identify the structure:

maxillary sinus

What could happen if a maxillary sinus has an infection?

It could infect a tooth root (vise versa if a tooth root is infected, it could spread to the maxillary sinus)

identify the structure:

mastoid process

What can permit spread of middle ear infections (mastoiditis)?

Mastoid air cells

- Mastoiditis complications can be vertigo, hearing loss, facial paralysis.

identify the structure:

groove for superior sagittal sinus

identify the structure:

groove for epidural arteries

identify the structure:

arachnoid granulations

identify the structure:

subarachnoid space (CSF filled)

What are the vessels shown on the skull?

Diploic and emissary veins

identify the structure:

cribiform plate

what structures run through the cribiform plate of the ethmoid bone?

olfactory nerve (CN I)

what structures run through the foramina shown?

olfactory nerve (CI)

identify the structure:

crista galli

identify the structure:

crista galli

identify the structure:

Frontal crest

Identify the structure at #1

Frontal sinus

Identify the structure at #2

Superior and middle concha (ethmoid bone)

Identify the structure at #3

Crista galli

Identify the structure at #4

Sphenoid sinus

Identify the structure at #5

Hypophyseal fossa

Identify the structure at #6

Inferior concha

Identify the structure at #7

Incisive canal

Identify the structure at #8

Palatine process (maxilla)

Identify the structure at #9

Horizontal plate (palatine)

Identify the structure at #10

Pterygoid plates

identify the structure:

hypophyseal fossa