4 - Skull Anatomy

Question 1

Name for upper part of cranium

Answer 1

Cranial vault

Question 2

Name for lower part of the cranium

Answer 2

Cranial floor

Question 3

Structure of skull bones

Answer 3

Hard outer layer of bone surrounding a soft, spongy layer

Question 4

Suture where frontal and parietal bones joint

Answer 4

Coronal suture

Question 5

Name of suture between parietal bones

Answer 5

Sagittal suture

Question 6

Name of suture where parietal and occipital bones joint

Answer 6

Lambdoid suture

Question 7

Name for lateral suture where frontal, parietal, temporal and sphenoid bones join

Answer 7

Pterion

Question 8

Sphenoid bone

Answer 8

Part of skull near orbit

Question 9

Particularly dangerous area to fracture skull

Answer 9

Pterion. Skull is thin, overlies an artery

Question 10

Two parts of frontal bone

Answer 10

Vertical part (forms forehead) Horizontal part (projection into the head, where there is a 90 degree bend into the orbit - also called orbital plates). Forms part of cranial floor

Question 11

Shape of parietal bones

Answer 11

Roughly rectangular, moulded to contour of brain

Question 12

Shape of occipital bone

Answer 12

Relatively flat, moulded to contour of brain. Very prominent bulge (external occipital protuberance).

Question 13

Temporal bone

Answer 13

Most anterior part is called the ‘squamous part’ Has three bony projections from squamous part.

Question 14

Three bony processes coming off temporal bone

Answer 14

1) Anterior projection is the zygomatic process of the temporal bone. Articulates with the zygoma (cheekbone). 2) Mastoid process projects posteriorly, inferiorly, has air cells, place where muscles attach. 3) Deep process is styloid process. Sharp point. Muscles associated with midline structures (eg tongue) attach here.

Question 15

Structure on the interior part of temporal bones

Answer 15

Petrous part of the temporal bone. A wedge-shaped part of bone that projects into cranial cavity, forming part of cranial floor.

Question 16

Sphenoid bone

Answer 16

Not really visible from exterior of skull. Mostly within the skull. Made up of greater, lesser wings, superior orbital fissure.

Question 17

*Sphenoid bone

Answer 17

Question 18

Where does the pituitary gland sit?

Answer 18

In the body of the sphenoid

Question 19

Telencephalon

Answer 19

Cerebral hemispheres

Question 20

Metencephalon

Answer 20

Pons and cerebellum

Question 21

Number of cranial nerves

Answer 21

Twelve pairs

Question 22

Fossae of the cranial base

Answer 22

Anterior, middle and posterior cranial fossae

Question 23

What does the anterior cranial fossa house?

Answer 23

Frontal lobe

Question 24

What makes up anterior cranial fossa?

Answer 24

Frontal bones, lesser wing of sphenoid, ethmoid bone

Question 25

Through which structure do axons of olfactory epithelium travel?

Answer 25

Cribiform plate of ethmoid bone

Question 26

What forms the middle cranial fossa?

Answer 26

Greater wings of sphenoid anteriorally, petrous part of temporal bone posteriorally

Question 27

What makes up posterior cranial fossa?

Answer 27

Occipital bone

Question 28

Foramen in anterior fossa

Answer 28

Cribiform plate (olfactory nerve)

Question 29

Foraminae in middle cranial fossa 1 2 3 4 5 6

Answer 29

• Hypophysial fossa (pituitary gland) • Optic canal (optic nerve, ophthalmic artery) • Superior orbital fissure (nerves to extraocular muscles and branches of trigeminal nerve) • Foramen rotundum (maxillary nerve) • Foramen ovale (mandibular nerve) • Foramen spinosum (middle meningeal artery)

Question 30

Foraminae in posterior cranial fossa 1 2 3 4

Answer 30

• Internal acoustic meatus (facial and vestibulocochlear nerves) • Jugular foramen (IX, X, XI, internal jugular vein) • Hypoglossal canal (hypoglossal nerve) • Foramen magnum

Question 31

Path of middle meningeal artery in skull

Answer 31

Enters skull through foramen spinosum, then grooves in bone outwards

Question 32

Location of internal auditory meatus

Answer 32

In the more vertical, posterior part of petrous temporal bone

Question 33

Location of jugular foramen

Answer 33

In the split between the petrous temporal bone and the occipital bone. Not a hole in a bone, but a space between two bones

Question 34

Location of hypoglossal canal

Answer 34

In occipital bone, between occipital condyles

Question 35

What does the dura attach to?

Answer 35

Skull and arachnoid

Question 36

Most delicate of meninges

Answer 36

Pia mater

Question 37

What are associated with the meninges?

Answer 37

Potential spaces (extradural space between dura and skull, subdural space between dura and arachnoid, subarachnoid space)

Question 38

What happens if the meningeal artery is ruptured?

Answer 38

Extradural space

Question 39

What often leads to a subdural haemorrhage?

Answer 39

Venous bleeding.

Question 40

Where does CSF circulate?

Answer 40

Subarachnoid space

Question 41

Projections of dura that don’t line interior surface of the skull 1 2 3 4

Answer 41

1) Falx cerebri (sickle-shaped, in sagittal plane) 2) Falx cerebelli 3) Tentorium cerebelli 4) Diaphragma sellae

Question 42

Role of dural projections

Answer 42

Prevent twisting of brain

Question 43

Attachments of falx cerebri

Answer 43

In line with sagittal suture, back to the interior of the external occipital protuberance

Question 44

Tentorium cerebelli 1 2 3 4

Answer 44

1) In the horizontal plane. 2) Crescent-shaped. 3) Grooves in posterior cranial fossa. 4) Separates cerebral hemispheres above from cerebellum below

Question 45

Falx cerebelli

Answer 45

Separates cerebellar hemispheres

Question 46

Diaphragma cellae

Answer 46

Roofs the pit in the body of the sphenoid

Question 47

Name for sinus formed by dura splitting to form falx cerebri

Answer 47

Superior sagittal sinus

Question 48

Where does venous blood of the brain drain?

Answer 48

Into dural sinuses. Where dura splits to form dural partitions. These form dura, epithelium-lined sinuses.

Question 49

What drains into dural sinuses? 1 2 3

Answer 49

1) Emissary veins from scalp. 2) Diploic veins (from spongy bit of skull) 3) Blood from brain