Anatomy II: Lecture 15 Osteology of the Skull

Question 1

What underlies the brainstem?

Answer 1

Bones of the base of the skull

Question 2

What type of bones are the bones of the base of the skull?

Answer 2

Endochondral

Which means they are preceded by carilage

Question 3

What type of bones are the bones forming the sides and roof of the skull?

Answer 3

Dermal bones
(Which means they are not preceded by cartilage)
(They are the bone that makes up the face)

Question 4

What forms the branchial arches?

Answer 4

Cartilage-replacement elements

Question 5

Neoteny of the skull

Answer 5

Failure to replace cartilage with bone in the adult
(Animals that do this: sharks, skates, and rays)
(something that resembles fetal characteristics: Here, it is the loss in the ability to replace cartilage with bone)

Question 6

The skull is a combination of

Answer 6

cartilage, dermal bone, and/or endochondral bone

Question 7

Openings in the skull are called _____

They allow passage to ____

Answer 7

Foramina

Nerves and blood vessels

Question 8

Cartilaginous capsules develop to enclose ____

Answer 8

Special sensory organs such as olfactory apparatus, eyes, and semicircular canals

Question 9

The skull is made of two components. What are they?

Answer 9

Chondrocranium and Dermatocranium

Question 10

Chondocranium is made of

Answer 10

Neurocranium: Cartliage and/or endochondral bone

Splanchnocranium (viscerocranium): Cartilage and/or endochondral bone

Question 11

Dermatocranium is made of

Answer 11

Dermal bone

Question 12

What is made up of the mass of cartilage that condenses beneath the embryonic brain and the bones that replace the cartilage?

Answer 12

The braincase, or neurocranium

Question 13

What contains the three pairs of cartilaginous capsules?

Answer 13

Braincase

Question 14

What are the two pairs of cartilaginous plates of the neurocranium?

Answer 14

Parachordals (Flanks the cranial end of the notochord)

Prechordals (Hypophyseals) (Cranial to notochord and parachordals)

Question 15

What is the posterior wall of the neurocranium?

Answer 15

Foramen Magnum

Question 16

T/F the roof of the neurocranium is usually closed?

Answer 16

False: They are usually open

Question 17

What represents the primitive vertebrate braincase?

Answer 17

Bones of basicranium (within the Neurocranium)

Question 18

Where do all nerves and vessels passing to and from the brain pass through?

Answer 18

Through the foramina of the bones of the basicranium

Question 19

What are the five bones of the basicranium?

Answer 19

Ethmoid
Sphenoid
Left and Right Temporals
Occipital bone

Question 20

What is the only basicranial bone that is entirely preformed in cartilage?

Answer 20

Ethmoid Bone***

Others are mostly preformed, but they have dermal bone components too

Question 21

What are the components of the ethmoid?

Answer 21

Cribriform plate 
Crista Galli 
Perpendicular plate 
Labyrinth 
Ethmoid air cells

Question 22

What is the attachment for falx cerebri?

Answer 22

Crista galli

Question 23

What contains superior and middle nasal conchae?

Answer 23

Labrinth of the ethmoid bone

Question 24

What are the components fo the sphenoid?

Answer 24

• Pterygoid plates
• Body
• Greater and lesser wings

Question 25

What are the components of the pterygoid plates of the sphenoid?

Answer 25

Medial and lateral plates hang down Dermal components attached to endochondral portion of sphenoid base Lateral Medial

Question 26

What are the components of the body of the sphenoid?

Answer 26

Hypophyseal fossa | Four clinoid processes

Question 27

T/F the Greater wings are the lower flaps

Answer 27

False: They contain lower and upper flaps

Question 28

The greater wings' lower flaps of the sphenoid bone contribute to the cranial fossa that contains the

Answer 28

temporal lobes of the brain

Question 29

What is the passageway for V2?

Answer 29

Foramen rotundum of the greater wings' lower flaps of the sphenoid bone (V2 = Second part to cranial nerve five)

Question 30

What is the passageway for V2

Answer 30

Foramen ovale of the greater wings' lower flaps of the sphenoid bone (V3 = the third part to cranial nerve five)

Question 31

What is the passageway for the middle meningeal vessels?

Answer 31

Foramen Spinosum of the greater wings' lower flaps of the sphenoid bone

Question 32

What are the two foraminae of the upper flaps of the greater wings in the sphenoid bone?

Answer 32

Optic canal | Anterior clinoid process

Question 33

What are the three foraminae of the lower flaps of teh greater wings in the sphenoid bone?

Answer 33

Foramen rotundum Foramen ovale Foramen spinosum

Question 34

What surrounds the ear apparatus?

Answer 34

Petrous part of the temporal bones

Question 35

Where is the first pharyngeal pouch growing and what does it form?

Answer 35

Petrous part of the temporal bones | Expands to form the middle ear chamber

Question 36

Where are the cavities that connect the pharynx to the eustachian tube?

Answer 36

Petrous part of the temporal bones

Question 37

What forms the carotid canal for the internal carotid canal?

Answer 37

Petrous part of the temporal bones

Question 38

What is a mass of air-filled outpocketings (air cells) from petrous part?

Answer 38

mastoid process of the temporal bones

Question 39

The styloid process of the temporal bones:

Answer 39

- Are derived from second-gill arches - Fuses with petrous portion in front of mastoid - Attachment site for muscles and ligaments

Question 40

The squamous part of the temporal bones are

Answer 40

Thin sheets of dermal bone, forming lateral wall of braincase ABOVE auditory meatus

Question 41

What is part of the temporal bone that forms a ring of dermal bone around the eardrum?

Answer 41

Tympanic part It expands after birth to become the external auditory meatus leading to ear drum from the outside

Question 42

What is a large dermal bone that forms the lower back of the head?

Answer 42

Squamous part of the occipital bone

Question 43

What forms from four separate bones that fuse around the spinal cord to form the foramen magnum?

Answer 43

Basilar part of the occipital bone

Question 44

T/F the frontal bone is paired in fetus and fused in adults

Answer 44

True

Question 45

Where can the supraorbital foramina be found?

Answer 45

In the frontal bone of the membrane bones of the skull

Question 46

What do the maxillary bones of the membrane bones of the skull contain?

Answer 46

The alveolar process and the infraorbital foramina

Question 47

What creates the superior and inferior temporal lines?

Answer 47

The parietal bones of the membrane bones of the ksull

Question 48

What the membrane bones of the skull?

Answer 48

``` Frontal bone maxillary bones Zygomatic bones Nasal Bones Parietal Bones ```

Question 49

What are the bones of the anterior skull?

Answer 49

``` Sphenoid: Greater wing Sphenoid: Lesser wing Ethmoid Lacrimal Vomer ```

Question 50

What are the occipitals of the base of the skull?

Answer 50

``` Occipital condyles Foramen magnum Supreme, superior, inferior nuchal lines External occipital protuberance Pharyngeal protuberance ```

Question 51

What does the body of the mandible contain?

Answer 51

mental protuberance and mental foramen

Question 52

The posterior cranial fosse contains the

Answer 52

cerebellum, pons, and medulla