1 - Zill - Skull

Question 1

Why is the risk of hematomas so high in the skull?

Answer 1

There is no room inside cranial cavity, cavity molded to brain like glove

Question 2

Skull Sutures

Answer 2

Fibrous connective tissue joints

Progressively fuse with age

Question 3

Calvarium

Answer 3

Skull Cap

Question 4

Bones of Skull Cap

Answer 4

Frontal

Parietal (2)

Occipital

Temporal (2)

Sphenoid

Question 5

Answer 5

Question 6

Junction of Temporal Sphenoid, Parietal, and Frontal Bones?

Clinical Relevance?

Answer 6

Pterion (“tear-ee-on”)

Skull fractures easily here, clinically important for epidural hematoma

Question 7

Fontanelles

Answer 7

Membranes that link bones at birth, aka soft spots

Anterior @ Bregma

Posterior @ Lambda

Lateral @ Pterion

Question 8

What can be used to access the Superior Sagittal venous sinus in neonates?

Answer 8

Anterior Fontanelle

Question 9

Three Layers of Skull bone?

Answer 9

1 & 3: Inner/Outer - Hard Cortical Bone

2: Middle - Soft spongy bones, Diploe

Question 10

Diploic Veins

Clinical Importance?

Answer 10

Course in diploe, connect cranial cavity and surface of skull

- - -

Can transmit infection from scalp to brain via emissary veins

Question 11

Emissary Veins

Answer 11

Connect:

Scalp to Diploe

Scalp to Sinus

Diploe to Sinus

Connect Outside to Venous Sinus; can transmit infections this way

Question 12

Bridging Vein

How are these different from Emissary Veins?

Answer 12

Connect surface of brain (cerebral vein)** to **venous sinus

“Inside to venous sinus”

- - -

Remember, emissary veins connect “Outside to venous sinus”

Question 13

Blood Supply to Calvarium

Outer and Inner?

Clinical?

Answer 13

Outer: Arteries to Scalp

Inner: Meningeal Arteries

Clinical: Skull fracture @ pterion can cause bleeding of Meningeal arteries, and lead to epidural hematoma

Question 14

Layers of the Scalp (5)

Answer 14

Mnemonic is SCALP!

1. S: Skin - Hair, sweat, sebaceous glands
2. C: Connective Tissue - Surround vessels, em. veins
3. A: Epicranial Aponeurosis - Moveable tendinous sheet
4. L: Loose Areolar Tissue - Connect apon. and perio, emissary veins cross
5. P: Periosteum - CT layer on outer side of calvarium

Question 15

Spreading of Infections Through Scalp

Clinical?

“Scalping” - What layers?

Answer 15

Clinical: Infections can spread through loose areolar layer, deep to epicranial aponeurosis (layers 3 and 4)

- - -

Scalping someone is removal of area between the same two layers, 3 and 4

Epicranial Aponeurosis / Loose Areolar Tissue

Question 16

Nerves of Scalp:

Branches of What?

Additional Innervation?

Answer 16

Branches of Trigeminal (V)

V1: Supraorbital N., Supratrochlear N.

V2: Zygomatico-Temporal N.

V3: Auriculo Temporal N.

Lesser Occipital N. - C2 Ventral Ramus

Greater Occipital N. - C2 Dorsal Ramus

Question 17

Arteries of Scalp:

Mainly branches of what major vessel?

Why can these bleed excessively?

Major named branches?

Answer 17

Internal and External Carotid A. (some Ophthalmic A.)

Can bleed profusely due to high anastomoses

1. Opthalmic Branches:
   
   1. ​Supraorbital A.
   2. Supratrochlear A.
2. External Carotid Branches:
   
   1. ​Superficial Temporal A.
   2. Posterior Auricular A.
   3. Occipital A.

Question 18

Answer 18

Question 19

Temporal Bones Parts (4)?

Answer 19

1. Mastoid Process: Hard, palpable behind ear
2. Squamous Part: Flat, above ear
3. Tympanic Part: Anterior to External Auditroy Meatus
   
   1. ​Petrous Part: Inside skull

Question 20

Clinical Fractures of Lateral Skull?

Clinical relevance of Temporo-Mandibular Joint?

Answer 20

1. Zygomatic Bone (cheek)
2. Maxillary Bone-Zygomatic Process
3. Temporal Bone-Zygomatic Process
   - - -

“TMJ” Disorders

Question 21

Answer 21

Question 22

What bone serves as the “core” of the skull?

Answer 22

Sphenoid

Turkish Saddle

Question 23

Major Landmarks of Sphenoid Bones

Answer 23

Lesser Wing - above Superior Orbital FIssure

Greater Wing - Below Superior Orbital Fissure (extends laterally)

Sella Turcica - “Turkish Saddle” - Depression and Location of Pituitary Gland

Question 24

Posterior Portion of Sella Turcica?

Clinical Relevance?

Answer 24

Clivus

Meningioma at Clivus

Complex symtoms, many can be present (blurry vision, nauseu, eating, balance)

Question 25

Cranial Cavity Depressions?

Answer 25

Fossa(e)

1. Anterior Fossa: Roof of nasal cavity, orbit
   
   1. Cranial Nerves: CN 1 (Cribriform Plate)
   2. Bones: Frontal, Ethmoid, Sphenoid
2. Middle Cranial Fossa: Orbit, nasal cavity, face
   
   1. Cranial Nerves: CN 2 - CN 6
   2. Pituitary, Brain Stem
3. Posterior Cranial Fossa: Face, oral cavity, neck
   
   1. Cranial Nerves: CN 7 - CN 12
   2. Foramen Magnum, spinal cord, Vertebral a.