Cranium

Question 1

What is a fontanelle?

Answer 1

Where cranial bones intersect (at the suture lines) in neonates, infants, and early toddlers.

Question 2

3 fontanelles

Answer 2

1) anterior
2) posterior
3) accessory (temporal/mastoid, sphenoid, sagittal)

Question 3

What is the cranium?

Answer 3

The full skull, including the mandible.

Question 4

What is the calvarium (including alternative name)? What bones are included?

Answer 4

AKA neurocranium; it is the vault bones (no facial bones) which make the protective brain case.

Bones included: frontal, parietals, superior temporals, superior occiput, sphenoid, ethmoid

Question 5

What is the calotte?

Answer 5

The ‘autopsy cut’ of the skull.

Question 6

What is the viscerocranium (including alternative name)?

Answer 6

aka splanchnocranium; it is the cranial base which includes the bottom portions of the occiput and temporal bones.

Question 7

What is the difference between the neurocranium and the viscerocranium?

Answer 7

The origin site of the bones. Viscerocranium originates from cartilage (endochondral ossification), while the neurocranium is created by intramembranous ossification (no cartilage stage).

Question 8

Where is are the internal and external laminae of the cranial bones found?

Answer 8

It’s the chocolate cookie portion of the bone oreo–the most internal and most external table of bone, dense, woven and hard.

Question 9

How do you pronounce diploe?

Answer 9

Dip- low- ee. Like Zoe.

Question 10

What is diploe?

Answer 10

The ‘cream filling’ portion of the bone oreo–the middle table of bone, more fluffy and less dense.

Question 11

How is an inca bone formed?

Answer 11

The inca bone is formed when the viscerocranium bone and the neurocranium bones meet but don’t fully integrate well, leaving an extra suture line that makes the ‘extra’ inca bone(s).

Question 12

What are the functional components of the skull? (9 total)

Answer 12

1) brain case/protection
2) optic sensory capsule (eye)
3) olfactory sensory capsule (nose)
4) respiratory function (breathing & humidification)
5) otic sensory capsule (ear)
6) vestibulocochlear sensory capsule (balance via inner ear/temporal bone/mastoid)
7) postural function (standing upright/having balance)
8) masticatory function (chewing)
9) vocal function (mouth, throat, hyoid, sinuses)

Question 13

What are the 3 mater of the brain and what is their location?

Answer 13

1) Pia mater, most internal meningeal layer right against brain
2) arachnoid mater, middle meningeal layer, very light and lacy
3) dura mater, most external meningeal layer, is against skull

Question 14

What are the 2 special points of dura mater, and where are they located?

Answer 14

falx cerebri–sickle shaped fold of dura mater which attaches approximately at the crista galli

falx cerebelli– sickle shaped fold of dura mater that attaches to the internal squama of the occiput

Question 15

These are the main vascular drainage parts of the brain.

Answer 15

Venous sinuses, sulci, and the jugular vein.

Question 16

What are arachnoid granulations?

Answer 16

Outcroppings of the arachnoid mater that make indentations in the skull.

Question 17

Name the 4 emissary foramina. What is the purpose of emissary formaina?

Answer 17

1) cecum
2) obelionic
3) mastoid
4) postcondylar

These are small holes that help take the pressure off the larger blood vessels that run beneath them (they’re pressure release valves). Not everyone has these foramina.

Question 18

What is the galea aponeurotica?

Answer 18

The connective tissue over the cranial vault (instead of muscle tissue).

Question 19

What are nuchal muscles?

Answer 19

Neck muscles.

Question 20

Where does the temporalis muscle attach?

Answer 20

Temporal line of the parietal bone, superior temporal surface of the sphenoid bone, and coronoid process of the mandible?

Question 21

Where do the nuchal muscles attach?

Answer 21

At the nuchal lines of the occiput.

Question 22

Ossification of the frontal bone: method and how many primary & secondary centers?

Answer 22

Intramembranous (in membrane); 2 primary centers and 6 secondary centers.

Question 23

When does the metopic suture begin to close/fuse?

Answer 23

Around age 2. Generally obliterated by age 8. Can have retained suture (genetic trait).

Question 24

Ossification of the parietal bones: method and how many primary centers?

Answer 24

Intramembranous; 1 center (rarely 2).

Question 25

Ossification of the occipital bone: methods and sites?

Answer 25

Above superior nuchal line: intramembranous.

Below superior nuchal line: endochondral (in cartilage).

Question 26

What are the 4 sutures which compose the parietal bone, and what bones do they connect?

Answer 26

1) Coronal suture (frontal-parietal)
2) Sagittal suture (parietal-parietal)
3) Lambdoidal suture (parietal-occipital)
4) Squamosal suture (parietal-temporal)