7. Cranium

Question 1

What bones are part of the axial skeleton?

Answer 1

-Skull bones
-Auditory ossicles (ear bones)
-Hyoid bone
-Ribs
-Sternum
-Bones of the vertebral column

Question 2

What are the 2 divisions of the cranial bones?

Answer 2

1. Calvaria (Skull Cap)
2. Floor or Base

Question 3

What does the Calvaria consist of?

4

Answer 3

-1 Frontal bone
-1 Occipital bone
-2 Parietal bones
-2 outer plates of compact bone and inner layer of spongy or trabecular bone called Diploë (red bone marrow)

Question 4

What does the floor or base consist of?

Answer 4

• 1 Ethmoid bone
• 1 Sphenoid bone
• 1 Occipital bone
• 1 Frontal bone
• 2 Temporal bones

Question 5

What are the 3 regions of the **base **of the skull?

Answer 5

1. Anterior Cranial Fossa
2. Middle Cranial Fossa
3. Posterior Cranial Fossa

Question 6

What does the Anterior Cranial fossa contain?

Answer 6

Houses frontal lobe of cerebrum

Question 7

What does the middle cranial fossa house?

Answer 7

Houses temporal lobes of cerebrum

Question 8

What does the posterior cranial fossa house?

Answer 8

Houses cerebellum, pons, medulla oblongata

Question 9

What are the parts of the frontal bone?

two

Answer 9

1. Vertical part (frontal squama)
2. Horizontal part

Question 10

What does the vertical part of the frontal bone contain(2), and what does it form?

Answer 10

-Contain the frontal sinuses, and frontal squama
-Forms the forehead and anterior part of cranial vault

Question 11

What does the horizontal part of the frontal bone make up?

three

Answer 11

-Orbital plates
-Part of roof of nasal cavity
-Greater part of floor of anterior cranial fossa

Question 12

What are the benefits of the orbital plates for an MRT?

Answer 12

How we determine the tilt side to side of the skull (no tilt when head straight)

Question 13

What is the glabella?

Answer 13

(Smooth elevation between superciliary arches)

Question 14

What are the articulations of the frontal bone?

six

Answer 14

-Parietal bones (right and left)
-Sphenoid
-Ethmoid
-Nasal bones
-Nasion
-Zygoma

PENNZS

Question 15

What landmarks on the parietal bones make up the widest portion of the skull?

Answer 15

Parietal eminences marks the widest portion of the skull

Question 16

What are the articulations of the parietal bone?

five

Answer 16

-Frontal
-Temporal
-Occipital
-Sphenoid
-Opposite parietal bone

Question 17

What forms the posterior cranial fossa?

Answer 17

Occipital bone

Question 18

Where is the location of the occipital bone on the skull?

Answer 18

Situated at the posteroinferior part of skull

Question 19

What are the four parts of the occipital bone?

Answer 19

1.Squama
2.Two occipital condyles
(Where C1 articulates with skull)
3.Basilar portion

Question 20

What are the landmarks located on the occipital bone?

6

Answer 20

-External Occipital Protuberance (Inion)
-Nuchal Lines
-Foramen Magnum
-Hypoglossal canals (Hypoglossal nerve)
-Jugular Foramen
-Foramen Lacerum

Question 21

What does the internal jugular vein do?

Answer 21

Internal Jugular vein drains venous blood from brain

Question 22

What are the articulations of the occipital bone?

Answer 22

-Atlantooccipital joint -C1
-Parietal bones
-Temporal
-Sphenoid

Question 23

What sections of the cranium does the temporal bone form?

Answer 23

-A large part of the middle cranial fossa and a small part of the posterior cranial fossa
-Forms the inferior lateral parts of skull

Question 24

What portions/bones does the temporal bone consist of?

Answer 24

1.Squamous portion
2.Tympanic portion
3.Petrous ridges or pyramids
4.Mastoid process

Question 25

What important landmarks are located on the temporal bone?

Answer 25

-Carotid Canal (Internal carotid artery) -Jugular Foramen -Foramen Lacerum -EAM -Internal Auditory Canal (vestibulocochlear and facial nerves (7&8)

Question 26

What parts of the cranium does the sphenoid form?

Answer 26

-Forms part of anterior and middle cranial fossa -Keystone bone of the cranial floor

Question 27

What does the sphenoid bone consist of?

Answer 27

1 Body 2 lesser wings 2 greater wings 2 pterygoid processes

Question 28

What part of the cranium does the ethmoid form?

Answer 28

-Part of anterior portion of the anterior cranial fossa -Medial wall of the orbits -**Superior portion of bony nasal septum** and sidewalls of nasal cavity

Question 29

Where is the ethmoid bone located?

Answer 29

-Anterior to the sphenoid and posterior to nasal bones

Question 30

Whatare the landmarks on the ethmoid bone ## Footnote five

Answer 30

1.Cribriform Plate 2.Crista Galli 3.Perpendicular Plate 4..Lateral Masses 5.Middle nasal conche

Question 31

What does the cribriform plate contain?

Answer 31

-Horizontal plate -Contains foramina (olfactory nerves 1)

Question 32

Where is the Crista Galli located? What attachment does it make up?

Answer 32

-Sits on cribriform plate Attachment for Falx Cerebri

Question 33

What does the falx cerebri do?

Answer 33

Is a membrane that separates hemispheres of brain

Question 34

What bone forms the superior part of the bony nasal septum

Answer 34

Perpendicular Plate

Question 35

What part of the ethmoid contains the ethmoid sinuses?

Answer 35

Lateral masses

Question 36

What two things does the lateral masses form?

Answer 36

-Form the superior and middle nasal conchae -Form the medial wall of orbits

Question 37

What makes up the zygomatic arch?

Answer 37

Zygomatic process (temporal bone) + Temporal process (zygomatic bone

Question 38

What portion of the temporal bone creates the Zygomatic process, Mandibular fossa, and Condyle of mandible

Answer 38

Squamous portion

Question 39

What forms the TM joint?

Answer 39

The condyle of mandible articulating with mandibular fossa

Question 40

What portion of the temporal bone consists of the EAM and Styloid process

Answer 40

Tympanic portion

Question 41

What does the hyoid bone hangs off of?

Answer 41

Styloid process on Tympanic portion of the temporal bone

Question 42

What portion of the temporal bone consists of the mastoid process

Answer 42

Mastoid portion

Question 43

What bone/landmark contains mastoid air cells that communicate with space in the middle ear

Answer 43

The mastoid process located on the mastoid portion of the temporal bone

Question 44

What portion of the temporal bone contains the cochlea and semi-circular canals?

Answer 44

Petrous portion

Question 45

What is another name for Petrous portion and which way does it project?

Answer 45

-Called petrous ridges or pyramids -Project anteriorly and medially

Question 46

What is the thickest, densest bone in skull?

Answer 46

Petrous portion of the temporal bone

Question 47

What is the landmark for the top petrous ridges?

Answer 47

Top of Ear Attachment (TEA)

Question 48

What part of the sphenoid forms posterior bony wall of nasal cavity?

Answer 48

The body

Question 49

What is on the superior surface of the body on the sphenoid?

Answer 49

Sella Turcica

Question 50

What houses the pituitary gland (hypophyseal fossa)?

Answer 50

Sella turcica

Question 51

What is the anterior border of the sella turcica called?

Answer 51

Tuberculum sellae

Question 52

What is the posterior border of the sella turcica called?

Answer 52

Dorsum sellae

Question 52

What is the top borders of dorsum of the sella turcica called?

Answer 52

Posterior clinoid processes

Question 53

Where do the pons sit against?

Answer 53

pons sits against the clivus

Question 54

What are the 2 parts of the lesser wings on the sphenoid?

Answer 54

Triangular and horizontal

Question 55

What do the lesser wings of the sphenoid form? ## Footnote four

Answer 55

1. posteromedial portion of the roofs of the orbits 2. optic foramen and the optic canals 3. upper margin of the superior orbital fissures 4. anterior clinoid processes

Question 56

What does the optic nerve and ophthalmic artery pass through?

Answer 56

Optic foramen

Question 57

What do the greater wings of the sphenoid form? ## Footnote Three

Answer 57

1. posterolateral walls of the orbits 2. Lower margin of the superior orbital fissures 3. Part of the middle cranial fossa

Question 58

What 3 foramens does the greater wings contain?

Answer 58

1. Foramen Ovale 2. Foramen Rotundum 3. Foramen Spinosum

Question 59

What does the Pterygoid processes of the sphenoid form?

Answer 59

-Inferior processes off the sphenoid body and greater wings -Forms the posterolateral region of nasal cavity

Question 60

What are the 3 types of skulls and what are their degrees?

Answer 60

Mesocephalic skull (47 degrees) Brachycephalic skull (54 degrees) Dolichocephalic skull (40 degrees)

Question 61

What bones form the anterior cranial fossa?

Answer 61

1. orbital part plates (frontal bone) 2. Ethmoid bone 3. lesser wings and anterior part of the body

Question 62

What are the 4 sutures of the skull?

Answer 62

Coronal Saggital Lamboidal Squamosal

Question 63

Where is the coronal suture located?

Answer 63

Between frontal and parietal

Question 64

Where is the sagittal suture located?

Answer 64

Superior mdiline between pariatal

Question 65

Where is the lambdoidal suture located?

Answer 65

Posteriorly between occipital bone and both parietal bones

Question 66

Where is the squamosal suture located?

Answer 66

Lateral part of skull between parietal and temporal bones

Question 67

What is the Bregma?

Answer 67

Where coronal and sagittal sutures meet, between the frontal and two parietal bones.

Question 68

What is the Lambda?

Answer 68

Posterior end of sagittal suture

Question 69

What is the Pterions (Right and Left)?

Answer 69

Junction of the parietal, temporal, and greater wing of sphenoid Landmark for the middle meningeal artery

Question 70

What is the Asterions (Right and Left)?

Answer 70

Posterior to the ear where the squamosal, saggital, and lambdoidal sutures meet

Question 71

What are some important landmarks located on the frontal bone? ## Footnote five

Answer 71

-Frontal eminences -Supraorbital margins -Superciliary arches -Supraorbital foramina -Glabella