Blood Supply and Coverings of Brain

Question 1

What is the Pachymeinx

Answer 1

Dura Mater (Periosteal and Inner Meningeal layers)

Question 2

What is the Leptomeninges

Answer 2

Arachnoid Mater

Pia Mater

Question 3

What are the reflections of the Dura Mater

Answer 3

Falx Cerebri
Falx Cerebelli
Tentorium Cerebelli
Diaphragma Sella

Question 4

Describe the Falx Cerebri

Answer 4

Dural Reflection:

• Through Longitudinal Fissure (see pg 54)
• Attaches to
• –Crista Glli of Ethmoid
• –Tentorium Cerebelli

Question 5

Describe the Falx Cerebelli

Answer 5

Dural Reflection:

• Along Vermis of Cerebellum
• Attaches to
• –Internal Occipital Crest

Question 6

Describe the Tentorium Cerebelli

Answer 6

Dural Reflection:

-Along Transverse Cerebral Fissure

Question 7

Describe the Diaphragma Sells

Answer 7

Covers Sella Turcica (depression in sphenoid bone for Pituitary Gland) with opening for Infundibulum

Question 8

Explain the Arterial Supply to the Dura

Answer 8

Anterior Meningeal A.
(from Ant/Post Ethmoidal Aa. which is a branch of the Ophthalmic A.)

Middle Meningeal A
(from Maxillary A.)

Posterior Meningeal A.
(from Ascending Pharyngeal/Occipital/Vertebral A.)

Question 9

Explain the innervation of the Dura

Answer 9

Middle Meningeal Branches
(from Trigeminal N.)

Upper Cervical Nerves

Question 10

What are the clinical implications of the Epidural Space

Answer 10

Epidural Haematoma

This is when the Middle Meningeal Aa. are lacerated

Question 11

What are the clinical implications of the Subdural Space

Answer 11

Subdural Haematoma

This is due to the tearing of veins

Question 12

Describe the structure of the Arachnoid Mater

Answer 12

• Avascular
• Does not dip into sulci
• Arachnoid Trabeculae:
• –Collagenous CT
• –Maintains patency of lumen

Arachnoid Villi

• Evaginations through dura into venous sinuses
• Become arachnoid granulations with age due to hypertrophy

Question 13

Describe the structure of the Pia Mater

Answer 13

2-3 cells thick

Creates a perivascular space for when A and V leave and enter brain - this is essentially an invagination of the pia mater

Question 14

Describe the structure os the Spinal Meninges

Answer 14

Contains no Periosteal (fibrous) layer of Dura Mater

Pia mater here forms 21 denticulate ligaments:

• Thickened anteriorly
• Give shiny appearance in midline (linea splendens)
• see pl. 165

Question 15

What is the location of the circle of Willis

Answer 15

Base of Interpeduncular Fossa

Question 16

Briefly describe the structure of the blood supply to the Spinal Cord

Answer 16

At the Medulla, Vertebral Arteries both form a single Anterior Spinal Artery. Additionally, 10-12 segmental (medullary Arteries from the Aorta join the Anterior Spinal Artery

Paired Posterior Spinal Arteries come from either Vertebral ARteries or PICA

Question 17

What are the consequences of occlusion to the Anterior Spinal Artery

Answer 17

Acute Thoracic Cord Syndrome:

• Paraplegia
• Incontinence

Question 18

Where is the blood supply to the spinal cord most vulnerable

Answer 18

Thoracic Region

Anterior Part of the Spinal Cord

Question 19

What are the features of the veins of the brain

Answer 19

• Valveless
• Thin walls
• No muscular tissue in Tunica Media
• Pierce Arachnoid Mater and Inner meningeal layer of Dura Mater
• End in Dural Venous Sinuses

Question 20

Which Dural Venous Sinus does the Superior Cerebral V. drain into?

Answer 20

Superior Sagittal Sinus

Question 21

Which Dural Venous Sinus does the Superficial Middle Cerebral V. drain into?

Answer 21

Cavernous Sinus

Question 22

Which Dural Venous Sinus does the Inferior Cerebral V. drain into?

Answer 22

Superior Sagittal Sinus
Transverse Sinus
Straight Sinus

Question 23

Which Dural Venous Sinus does the Superior and Inferior Cerebellar V drain into?

Answer 23

Transverse Sinus

Straight Sinus

Question 24

Describe the location of the Superior Saggital Sinus

Answer 24

From the internal occipital protuberance to the confluence on sinuses

Lies on the Convex attached border of the Falx Cerebri

See pl. 145

Question 25

Describe the location of the Inferior Sagittal Sinus

Answer 25

From the Inferior free border of the Falx Cerebri to the Straight Sinus

Question 26

Describe the location of the Straight Sinus

Answer 26

Goes inferoposterioly along the line of attachment of the Falx Cerebri to Tentorium Cerebelli at the Confluence of sinuses

Question 27

Describe the location of the Transverse Sinus

Answer 27

From the confluence of sinuses along the Posterolateral borders of Tentorium Cerebelli to the Sigmoid Sinus

Question 28

Describe the location of the Occipital Sinus

Answer 28

Runs from attached border of Falx Cerebri to the Conluence of Sinuses superior to it

Question 29

Describe the location of the Cavernous Sinus

Answer 29

From each side of the Sella Turcica. Along the upper surface of the body of sphenoid To the Superior and Inferior Petrosal Sinuses

Question 30

Describe the location of the Superior Petrosal Sinus

Answer 30

From the Anterolateral attached Margin of Tentorium Cerebelli. Along the posterior part of the Cavernous Sinus to the transverse Sinus where the Transverse Sinus curves inferiorly to form the Sigmoid Sinus

Question 31

Describe the location of the Inferior Petrosal Sinus

Answer 31

From the Posterior part of the Cavernous Sinus to the place where the Sigmoid Sinus becomes the internal Jugular Vein