Anatomy - Interior Of The Skull

Question 1

The roof of the cranial cavity is formed by the

Answer 1

Calvaria

Anterior: Frontal
Middle: Parietal
Posterior: Occipital

Question 2

Attachment of falx cerebri?

What is falx cerebri?

Answer 2

Frontal crest

Falx cerebri is part of the dura mater

Question 3

Frontal crest terminates at the beginning of the __

Answer 3

Groove for the superior sagittal sinus

which is the intradural venous structure

Question 4

Parietal bones have grooves from which artery?

Answer 4

Middle meningeal a.

Question 5

What are granular foveolae?

Answer 5

Small pits and depressions in the calvaria that host arachnoid granulations

Question 6

The floor of the cranial cavity has 3 large depressions:

Answer 6

Anterior
Middle
Posterior cranial fossa

Question 7

Anterior cranial fossa

Answer 7

Shallowest and most superior of the 3 depressions on the cranial cavity

Bones: frontal, ethmoid, sphenoid

Features:
Foramen cecum
Cribriform foramina
Anterior and posterior ethmoidal foramina

Question 8

Foramen cecum

Answer 8

In the frontal bone on the border with the ethmoid

For the passage of nasal emissary veins

Question 9

Cribriform foramina

Answer 9

In the cribriform plate

For the passage of axons of olfactory nerves

Question 10

Anterior and posterior ethmoidal foramina

Answer 10

For passage of ethmoid a. and v.

Question 11

The ethmoid forms a ___, and a ___ for ___.

Answer 11

The ethmoid forms a cribriform plate and a median crest, crista galli, for the attachment of the falx cerebri

Question 12

Middle cranial fossa

Answer 12

Posterior and inferior to anterior cranial fossa.

Bones: sphenoid, temporal

Question 13

Foramina of the Middle Cranial Fossa

Answer 13

Carotid canal
Optic canal
Foramen rotundum
Foramen lacerum 
Foramen ovale
Foramen spinosum
Superior orbital fissure

ROLS SOC

Question 14

What is the Sella Turcica?

Answer 14

“Turkish saddle”

centrally located upper part of body of the sphenoid

Question 15

The limbus of the sphenoid forms the __

Answer 15

Anterior boundary of the chiasmatic sulcus, which is formed as the continuation of the optic canals where the optic nerves cross

Question 16

What is the sella turcica formed by?

Answer 16

1. Tuberculum sellae - elevation at the posterior aspect of chiasmatic sulcus
2. Hypophysial fossa - depression housing pituitary gland
3. Dorsum sellae - bony ridge projecting superior with posterior clinoid processes as lateral edges

Question 17

Optic canal

Answer 17

Goes through lesser wing of sphenoid, found in the base

Opens into orbit

For passage of CN II and ophthalmic a.

Question 18

Superior orbital fissure

Answer 18

Located between greater and lesser wings of sphenoid

Opens into the orbit

For passage of:
CN III
CN IV
CN V1 (ophthalmic n.)
CN VI
ophthalmic veins

Question 19

Foramen rotundum

Answer 19

Located posterior to the medial end of he superior orbital fissure

Opens externally into the pterygopalatine fossa

For passage of CN V2 (maxillary n.)

Question 20

Foramen ovale

Answer 20

Opens inferiorly into the infratemporal fossa

For passage of:
CN V3 (mandibular n.)
Lesser petrosal n.
Accessory meningeal a.

Question 21

Foramen spinosum

Answer 21

Located posterolateral to f. ovale

Opens into infratemporal fossa

For passage of middle meningeal a.

Question 22

Blood supply to dura mater?

Answer 22

Middle meningeal a.

Question 23

Carotid canal

Answer 23

Opens into the cranium posteromedial to f. ovale

For passage of internal carotid a. and nerve plexus

Question 24

Foramen lacerum

Answer 24

Posterolateral to hypophyseal fossa

Partially filled with cartilage during life

Question 25

Posterior cranial fossa

Answer 25

Largest, deepest, and most inferior of the 3 cranial fossa

Question 26

The posterior cranial fossa is limited by___

Anteriorly
Laterally
Inferiorly/posteriorly

Answer 26

A: on the midline by dorsum sellae

L: superior border of the petrous part of temporal bone

I/P: occipital bone

Question 27

Bony features of posterior cranial fossa

Answer 27

Clivus - -a shallow depression formed by sphenoid body and basilar part of occipital bone. Slopes posteriorly

Internal occipital crest - runs along midline from f. magnum to internal occ. protuberance. Divides posterior cranial fossa into 2 bilateral depressions, the deep cerebellar fossae

Question 28

Foramen of the posterior cranial fossa

Answer 28

1. Foramen magnum
2. Jugular foramen
3. Internal acoustic meatus
4. Hypoglossal canal
5. Sinuses
   A. Inferior petrosal
   B. Sigmoid
   C. Transverse

Question 29

Foramen magnum

Answer 29

Largest foramen in the skull

Within occipital bone

For passage of:
Brainstem/spinal cord with meninges
Vertebral arteries
CN XI (spinal accessory n.)

Question 30

Jugular foramen

Answer 30

At the base of the petrous ridge of the temporal bone

For passage of:
CN IX
CN X
CN XI
sigmoid sinus as it becomes the superior bulb of the internal jugular vein

Question 31

Internal acoustic meatus

Answer 31

Anterosuperior to jugular foramen within petrous portion

For passage of:
CN VII
CN VIII
Labyrinthine a.

Question 32

Hypoglossal canal

Answer 32

Anterolaterally within the foramen magnum

For passage of:
CN XII

Question 33

Location of sinuses found in posterior cranial fossa

Answer 33

1. Inferior petrosal sinus
   - lateral to clivus
2. Sigmoid sinus
   - between temporal and occipital bones running towards jugular foramen
3. Transverse sinuses
   - extend laterally from internal occipital protuberance to join sigmoid sinuses