Cranial Cavity (Gray's)

Question 1

What bones make up the Calvaria and what sutures hold them together?

Answer 1

• Frontal, Parietal, and Occipital Bones

Coronal Suture - Between Frontal and Parietal Bones

Sagittal Suture - Between paired parietal bones

Lambdoid Suture - between Parietal and Occipital Bones

Question 2

What are the Bregma and Lambda?

Answer 2

Bregma
- Junction of Coronal and Sagittal Sutures

Lambda
- Juction of lambdoid and sagittal sutures

Question 3

What is the Falx Cerebri?

Answer 3

Specialization of Dura Mater that partially Separates the two cerebral Hemispheres

Question 4

What are the 5 layers of the scalp?

Answer 4

S - Skin
C - Connective Tissue (dense)
A - Aponeurotic Layer
L - Loose CT
P - Pericranium

Question 5

T or F: the skin, dense connective tissue, and aponeurotic layer of the scalp are tightly bound.

Answer 5

True

Question 6

What is contained in the dense connective tissue layer of the scalp?

Answer 6

Veins, Arteries, and Nerves that supply the scalp

Question 7

What layer of the scalp provides a point of attachment for the occipitofrontalis muscle?

Answer 7

Aponeurotic layer

Question 8

What is the point of the loose connective tissue layer of the scalp?

Answer 8

Separates the Aponeurotic layer from the skull allowing for movement of the scalp

Question 9

Why do injuries in which the dense CT layer of the skull is injured result in profuse bleeding?

Answer 9

1. This tissue is hightly vascularized

2. The Dense CT holds the vessel open

Question 10

Where do infections in the scalp tend to localize and why?

Answer 10

• Loose CT of the Skull

- This is due to its consistency

Question 11

What is the pericranium attached to and is it removable?

Answer 11

• Attached Directly to the Cranium

- Removable Except at the Sutures

Question 12

What are the 3 parts of the Aponeurotic Layer of the scalp?

Answer 12

Anterior: Frontal Belly of Occipitofrontalis
Posterior: Occipital Belly of Occipitofrontalis
Between: Epicranial Aponeurosis (galgea aponeurotica)

Question 13

What is the innervation of the occipitofrontalis muscles?

Answer 13

Facial Nerve (CN VII)

Question 14

What is an important distinction between the dura of the spinal cord and that of the brain?

Answer 14

• Dura of the Brain consists of 2 layers

- only 1 layer on the spinal cord comes through the foramen magnum

Question 15

What are the 2 layers of the dura of the brain and what are they in contact with?

Answer 15

1. Periosteal Layer - Firmly attached to the skull
2. Meningeal Layer - contacts the arachnoid mater

**Meningeal Layer continuous with spinal Dura Mater at Foramen Magnum

Question 16

What are the 4 dural partitions?

Answer 16

1. Falx Cerebri
2. Tentorium Cerebelli
3. Falx Cerebelli
4. Diaphragma Sellae

Question 17

What layer of the dura contains the meningeal arteries that supply the meninges?

Answer 17

Periosteal layer

Question 18

What innervates the meningeal layers?

Answer 18

• Small Meningeal Branches of the Three Divisions of the Trigeminal n. (CN V)
• Cervical nn. 1,2, and sometimes 3

Question 19

Falx Cerebri

• What is it?
• Location
• Anterior Attachment
• Posterior Attachment

Answer 19

Dural Partition

• Meningeal Layer passes between the two Cerebral Hemispheres

Anterior Attachment:
- Crista Galli (ethmoid) and Frontal Crest (frontal bone)

Posterior Attachment:
- Tentorium Cerebelli (it blends in with it)

Question 20

Tentorium Cerebelli

• What is it?
• Location

Attachments:

• Anterior
• Medial
• Lateral
• Posterior

Answer 20

Dural Partition

• Horizontally oriented between Cerebellum and Posterior Cerebral Hemispheres

Attachments
Anterior:
Anterior and Posterior Clinoid Processes

Posterior: Occipital bone along grooves of TRANSVERSE sinuses

Laterally: Superior border of petrous part of Temporal Bone

Medially: Just a free edge

Question 21

Falx Cerebelli

• What is it?
• Location

Attachments:

• Anterior
• Posterior
• Superior

Answer 21

Dural Partition

• Small midline projection of meningeal dura in posterior cranial fossa

Attachments:
Anterior: Free edge

Posterior: Internal Occipital Crest

Superior: Tentorium Cerebelli

Question 22

Diaphragma Sellae

• What is it?
• Location
• What passes through it

Answer 22

Dural Partition

• Horizontal shelf of meningeal dura that covers hypophyseal fossa in sella turcica
• Infundibulum passes through the center of this

Question 23

What 2 main arteries provide arterial blood to the brain?

Answer 23

• Vertebral

- Internal Carotid

Question 24

What do the internal carotid arteries form at the base of the brain within the cranial cavity?

Answer 24

• Cerebral Arterial Circle (of Willis)

Question 25

How do the vertebral arteries and carotid arteries enter the cranial cavity?

Answer 25

Vertebral
- Via Foramen Magnum

Carotid
- Via L and R carotid Canals

Question 26

Menigeal Arteries

• What do they supply
• Largest branch
• How do they enter the cranial Cavity

Answer 26

• The meninges, middle menigeal supplies 2/3 of the Dura
• Middle = Largest
• Middle enters crainal cavity via FORAMEN SPINOSUM

Question 27

Which meningeal artery is at risk in head trauma and why?

Answer 27

• Middle Menigeal

- Its close proximity to the pterion

Question 28

What does the venous drainage of the brain and cranial cavity?

Answer 28

Dural Venous Sinuses