Lec 2

Question 1

What are Fontanels?

Answer 1

Cartilage covering non fused portion of skull allowing for easy birth and facial molding

Question 2

Name the 3 Fontanels

Answer 2

Anterior, Sphenoid, Mastoid

Question 3

Describe the Anterior Fontanel

Answer 3

Trap shaped and separates the frontal and 2 parietal bones

Question 4

Describe the Sphenoidal Fontanel

Answer 4

Occupies are btwn sphenoid, parietal, temporal, and frontal bones

Question 5

Describe the Mastoid Fontanel

Answer 5

Btwn temporal, occipital, and parietal bones

Question 6

What is the final progression of the Fontanels

Answer 6

Replaced 18-24 months by forming sutures, premature fusion = Craniosynastosis

Question 7

What the the bones of the skull proper?

Answer 7

2 Parietal, 2 Temporal, 1 Frontal, 1 Occipital, 1 Sphenoid, 1 Ethmoid

Question 8

What are the bones of the Facial skull?

Answer 8

2 Maxilla, 2 Palatine, 2 Nasal, 2 Inferior Conchae, 2 Zygomatic, 2 Lacrimal, 1 Vomer, 1 Mandible

Question 9

The major frontal fissures are?

Answer 9

Supraorbital, Infraorbital, Mental fissures for CN V

Question 10

Describe the Post View archetecture

Answer 10

Lamboid fissure and sagittal fissure. Mastoid process is first to stick out from post view. Occipital condyle is the horizontal ridge. Wormian bones can be mistaken for fractures but are misconstruction of fissures.

Question 11

What are the fossa of the inferior portion of the inner skull?

Answer 11

Anterior, Middle, and Posterior Fossa

Question 12

Describe the Anterior Fossa

Answer 12

Formed by the frontal, ethmoid, body and lesser wing of sphenoid. Contains inferior and anterior parts of frontal lobe. Important structures are the Crista Galli and Cribiform Plate

Question 13

Describe the Middle Fossa

Answer 13

Crest of the sphenoid bone anteriorly, greater wings of sphenoid, squamous part of the temporal bone laterally, and petrous part of temporal bone posteriorly. Supports the temporal lobes of the brain and is the attachment point of tentoral fold. Structures are: Sella Turoca (pit gland loc), Sup Orbital Fissure, Foramen Rotunda, Foramen Ovale, Foramen Spinosum, and Foramen Lacrum

Question 14

Describe the Posterior Fossa

Answer 14

Anterior is dorsum sellae of sphenoid, lateral by petrous ridge of temporal and mastoid, base is occipital w/ foramen magnum. Contains the Cerebellum, pons, and medulla oblongata. Structures are internal acoustic meatus, internal jug foramen, hypoglossal canal, foramen magnum, and internal occipital ridge

Question 15

What are the attachment points for the Dura Mater

Answer 15

crista galli, clinoid process, petrous ridge, and internal occipital ridge

Question 16

Describe the Lateral view of the skull

Answer 16

Pterion is artifact of importance which is the union of parietal, frontal, greater wings of sphenoid, and squamous temporal. Contains arterial branch of middle meningeal artery which is easy to fracture and dmg

Question 17

Describe the dural folds

Answer 17

The Falx Cerebri is btwn 2 cerebral hemispheres, ant connected to crista galli, post to tentorium cerebeli at internal occipital ridge.
The tentorium emerges as dural fold from clinoid process of sphenoid and each ridge of temporal bone to meet falx cerebri. Separates cerebrum from cerebellum. Midline hiatus allows passage of brainstem.
Dorsum Sallae - covers pituitary gland

Question 18

What are the major sites of vulnerability of the brain

Answer 18

1. Epidural space - btwn periostial layer of dura mater and skull, fracture near meningeal vessels leads to realization of space due to blood fill
2. Major veins of subarachnoid space enter into dural sinuses and transverse the subdural space btwn arachnoid and dura mater
3. Arachnoid granulations are valves for exit of CSF

Question 19

What is an Epidural Hematoma

Answer 19

Skull fracture at pterion can dmg the middle meningeal artery (exits into cranium at foramen spinosum) which empties the blood into the epidural space. The blood dislocates brain giving it a lentricular shape. Severe displacement moves temporal lobe to herniate into brianstem leading to compression of CN3. Clinical presentation: Oculomotor palsies, pupillary dilation, ptosis, disruption of cortico-spinal tract

Question 20

Describe a Sub-dural Hematoma

Answer 20

Dmg to space where subarachnoid veins enter superior sagittal sinus leads to blood in the subdural space. Clinical presentations are headaches, lethargy, and slurred speech. Presentations due to increased CSF pressure

Question 21

What is a contusion?

Answer 21

Tear in fabric of brain damaging blood vessels and neurons (m and s) impacts CN 5,9,10 leading to headaches

Question 22

Describe a concussion

Answer 22

Blow to head leading to dizziness and disorientation. Sum can lead to chronic traumatic encephelopathy which are tangles in neurofibrils

Question 23

Describe ventricular system and path

Answer 23

Ventricles are source of CSF and made of 4 interconnected ventricles - 2 lateral and single 3rd and 4th. CSF formed at choroid plexus by filtrating blood. Path = lat vent - 2 foramen of monroe - 3rd vent - canal of iter - 4th - 2 foramen of Luschlea + Magenche - subarachnoid space. CSF moves by vessel pulsations

Question 24

What is hydrocephalus

Answer 24

Greater than 150ml of CSF = greater pressure, excess released by arachnoid granulations to sup sagittal sinus. At greater pressures the exits of CSF shut down and lead to blockage of the iter.
Caused by: congenital, acquired
Compresses thalamus, basal ganglia, and internal capsule
Symptoms are: headache, nausea, impaired balance

Question 25

What is pneumocephalus

Answer 25

Seat belt injury, fracture of frontal sinus lets CSF drain through nose causing a settling of brain leading to inflamed meninges and headaches

Question 26

What are the parts of the cranial venous system

Answer 26

1. Superficial temporal vein in connective tissue, emissary veins pierce and go to venous sinuses
2. Diploic veins are btwn two lamina of skull
3. Venous sinus are channels in dura mater and drain brian
4. Subarachnoid space continuous with capillary network of pia mater

Question 27

What is general venous path

Answer 27

Sup Cerebral veins - Sup Sagittal Sinus
Inf Cerebral veins - inf sagittal sinus - great vein of Galen - straight sinus
Both merge at confluens of sinus in occipital region - transverse sinus + sigmoid sinus - internal jugular vein

Driven by pressure and posture

Question 28

What are the kinds of stroke

Answer 28

Hemorrhagic and classical stroke

Question 29

Describe Hemorrhagic stroke

Answer 29

cause is hypertension and two types - intrecerebral and subarachnoid
Weak vessels ruptures and bleeds into brain occurs at aneurism or arteriovenous malformations
eg: int carotid passes through cavernous sinus, an aneursim = adoption of arterial pressure leading to swelling of ophthalmic veins in orbit developing pulsating exophtalamus (eyeball protrudes, flow of blood detected by stethoscope)

Question 30

Describe a classic stroke

Answer 30

Thrombosis of int carotid artery - mid meningeal art - striate art - impact on internal capsule and thalamus damaging axons

Question 31

Describe the architecture of the Circle of Willis

Answer 31

anterior communicating branch, bifurcation of internal carotid art, bifurcation of middle cerebral artery, basilar artery bifurcation … willis made of post cerebral, post comm, internal carotid, ant cerebral, and ant comm