3 Cran Vault Dura 12(1) 6r1g1c

Eastern Virginia Medical School

Cranial Vault & Dura Paul F. Aravich, Ph.D. Medical Gross Anatomy & Embryology 2012 Department of Pathology & Anatomy Glennan Center for Geriatrics & Gerontology & Department of Physical Medicine & Rehabilitation Eastern Virginia Medical School Norfolk, VA [email protected]

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Cranial Vault & Dura

Objectives: Concept map: The organization of the scalp and its danger zone.  Blood supply to the scalp  Openings for the cranial nerves  Dura mater & its reflections in the cranial vault  Dural sinuses & the venous drainage of the brain  Internal carotid, vertebral & middle meningeal aa 

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Clinical correlates

Clinical correlates

Scalp infections & lacerations  Periorbital Ecchymosis: Black eye vs. Raccoon eyes  CSF rhinorrhea & CSF otorrhea  Basilar venous plexus & metastatic/infection spread  Internal carotid artery aneurysm & CN II optic nerve  Fracture of the pterion and type of hemorrhage  Cavernous sinus thrombus 

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Outline: Cranial Vault & Dura Scalp  Cranial nerve openings  Dura mater  Dural sinuses  Internal carotid, vertebral & middle meningeal aa 

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Skin Connective tissue (sub. cut. tissue): vessels/nn Aponeurosis, epicranial see next slide Loose connective tissue to allow movement of 1st 3 layers Pericranium (periostium) tissue lining bone Clinical correlate

Factory/machine accidents entangling hair: Often pull-off scalp proper, causing a scalping injury

Scalp: Soft tissue covering cranial vault. Usually has hair.

Fig. 7.18 A, p. 539, Grant's Atlas 1999

Scalp proper

Scalp & its layers spell S.C.A.L.P.

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Epicranial aponeurosis: for occipitofrontalis m FYI. AKA galea aponeurosis

Aponeurosis = broad flat t.  Connects 2 bellies of the:



Epicranial aponeurosis

Occipitofrontalis m  A m of facial expression, e.g.  frontal belly wrinkles forehead & -elevates eyelids “I can’t believe that”  Occipital belly smoothes Occipital belly Frontal belly forehead skin Occipitofrontalis m  CN VII facial n FYI: other mm attach to the -innervates both bellies epicranial aponeurosis, e.g., superior auricular m, which elevates the auricle (external ear)

Fig. 7.12 A, p. 535, Grant's Atlas 1999



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Scalp Arteries, e.g.

Supraorbital a.

Internal carotid a: 2 brr of ophthalmic a  

Supraorbital a. Supratrochlear a.

Superficial temporal a.



Supratrochlear a.

See Orbit lecture



External carotid a. brr e.g., 

Occipital a. Superficial temporal a.



FYI post. auricular a. etc.



Note multiple anastomoses between internal carotid (sup orb/sup trochlear aa) & external carotid aa

Occipital a.

(superficial temp/occ. etc. aa) Fig. 7.14 B, p. 537, Grant's Atlas 1999

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Laceration of scalp aa: 

Bleed like crazy

Clinical correlate

Bleed from both ends of laceration  Due to lots of anastomoses 

 



FYI. Also, held open by subcutaneous collagen fibers FYI. Good news: washes away infections better than other sites

Scalp lacerations Most common head laceration requiring surgery FYI. Hair apposition technique w/ tissue glue for superficial, non-bleeding wound



http://www.aafp.org/afp/2008/1015/p945.html

FYI. For hemostasis (stoppage of bleeding): provide local anesthetic w/ epinephrine & manual pressure; clip/clamp larger aa

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They are in the diploe “Di-Plo-E” (AKA spongy layer or cancellous bone) of the calvaria (skullcap). Bone marrow is also in the diploe By contrast, the external & internal surfaces of the calvaria are made of compact (cortical) bone.

Fig. 7.16, p. 538, Grant's Atlas 1999

Diploic veins of skull:

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Emissary veins: connect the skull surface w/ cranial vault Superficial v

Emissary v. They drain into Dural sinus: part of the venous drainage system of brain; discussed later

Plate 102 upper, Netter

Diploic v.

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Calvaria has foramina for emissary vv. anterior

Emissary v. foramina (present in various skull bones)

Fig. 7.4 B, p. 841, Moore 1999

FYI. Indentations for arachnoid granulations are bigger: Granulations shunt CSF into dural sinuses

posterior

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Epicranial aponeurosis: scalp danger zone 

Clinical correlates

Infections deep to epicranial aponeurosis Can gain access to cranial vault  Via Emissary veins  Scalp infection then becomes intracranial infection 



Infections superficial to epicranial aponeurosis 

Much less likely to cause intracranial infection

Q. Name another “danger space?” Ans. Retropharyngeal danger space. A fascial plane behind the visceral compartment of the neck 12

Scalp epicranial aponeurosis

Superficial v Diploic v

Emissary v

Emissary v

Dural sinus

The Scalp danger space: deep to epicranial aponeurosis

Modified from eMedicine’s copy of a Snell’s 5th Ed. Anatomy diagram http://emedicine.medscape.com/article/834808-overview

Boxes: scalp proper. Most of vv. are deep to epicran aponeurosis

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Periorbital Ecchymosis ec-key-mosis “Peri:” around eyes. “Ecchymosis:” subcutaneous hematoma 

Occipitofrontalis muscle: attachments: 







Posterior attachment: mostly occipital bone & part of temporal bone -prevents scalp bleeding/infection from going into neck Lateral attachment: mostly zygomatic arches -prevents scalp bleeding/infection from going laterally

Anterior attachment: skin of forehead/eyelids, not bone 



Clinical correlate

Scalp blood can drain into loose connective tissue of eyelids/root nose

“Black eye: local periorbital bleed; occurs w/in hrs post trauma “Raccoon eyes:   

Occurs 2-3 days post trauma Always Bilateral One cause: bleed from anterior basilar skull Fx can drain into lids (i.e., fracture to cribriform plate in floor of anterior cranial fossa)

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Black eye vs Raccoon eyes

http://en.wikipedia.org/wiki/Black_eye

Local periorbital subcutaneous hematoma due to bleed from facial trauma

Bilateral subcutaneous hematoma due to bleed from basilar skull fracture http://hgimg.com/bookimages/5/2461.1.jpg

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Scalp lacerations 

Lacerations superficial to epicranial aponeurosis 



Clinical correlates

Do not gape (aponeurosis holds edges close)

Lacerations deep to epicranial aponeurosis 

Gape widely; much more bleeding FYI: especially in coronal plane due to opposite pulls of 2 bellies of occipitofront m



Suture to adjacent epicranial aponeurosis

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Outline: Cranial Vault & Dura Scalp  Cranial nerve openings  Dura mater  Dural sinuses  Internal carotid, vertebral & middle meningeal aa 

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Review. Cranial vault Openings: CN I –VI CN I olfactorycribriform plate ethmoid bone foramina CN II optic-optic canal; w/ ophthalmic a.

Lesser wing

V2 trigeminal n. maxillary br.-foramen rotundum

CN III/IV/V1/VI:* superior orbital fissure “count” Greater wing

Fig. 7. 4B, p. 527, Grant’s Atlas 1999

V3 trigeminal n. mandibular br.-foramen ovale middle meningeal a.: foramen spinosum

*CN III-oculomotor, IV-trochlear, V1 trigeminal-ophthalmic br, VI-abducens

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CN VII/VIII-facial/vestibulocochlear: internal auditory meatus on upper posterior face of petrous part of temporal bone

CN IX/X/XI:* jugular foramen on post. lower face of petrous; “count”

*CN’s: IX-glossopharyngeal, X-vagus, XI-spinal accessory

CN XII hypoglossal: hypoglossal canal in occipital bone

Fig. 7. 4B, p. 527, Grant’s Atlas 1999

Review. Openings: CN VII - XII

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I

IX/X/XI

III

IV hard Hypophyseal to see fossa

VI VII/VIII

“Superior” view of cranial vault w/ dura; orbital portion of frontal bone removed to show eye

II

III

V

I

XII

VI VII/VIII

XII

cord

V

EVMS Division of Anatomy photo

II

clivus

Middle cranial fossa IV hard to see

eye

IX/X/XI

CN’s: cranial vault

Crista galli

eye

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Aneurysm here 

Can affect vision

Internal carotid a cerebral segment

Clinical correlate

IX/X/XI

“Superior” view of cranial vault w/ dura; orbital portion of frontal bone removed to show eye

eye CN II

III III Hypophyseal fossa V VI VII/VIII XII

Internal carotid a

EVMS Division of Anatomy photo



CN II

Crista galli

CN II optic n: near cerebral part of internal carotid a

eye

cord

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Clivus: mostly made from basilar part of occipital bone* *AKA “basiocciput”

brain stem

Div. Anatomy EVMS

Hemisected head

Squamous (“plate-like”) part of Occipital bone

10 CN’s connect w/ Allbrainstem but CN’s CN I olfactory, & XI spinal acc

Dotted line: foramen magnum 22

Outline: Cranial Vault & Dura Scalp  Cranial nerve openings  Dura mater  Dural sinuses  Internal carotid, vertebral & middle meningeal aa 

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Review. Meninges: “3 mothers” or coverings for the central nervous system 

Tuff mother:

Dura mater

Superficial/outer layer  Adheres directly to inside surface of cranial vault 



Spider mother: 



Arachnoid mater

Intermediate

Tender mother:

Pia mater

Deepest  Adheres directly to brain/cord 



Leptomeninges: arachnoid mater + pia mater 24

“Superior” view of cranial vault w/ orbital portion of frontal bone removed to show eye

eye

EVMS Division of Anatomy photo

Crista galli

Middle cranial fossa e.g., dura lining basal Hypophyseal surface of fossa posterior cranial fossa clivus

Dura: adheres to the inside surface of the cranial vault

eye

cord

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Base of cranial vault w/o dural lining Anterior

Div. Anatomy, EVMS

Basilar skull

Posterior

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Review. Cranial vault Meninges: 3 “spaces” superficial to deep bone Epidural: a potential “space” (dura normally adheres to inside of cranial vault) Contents. Middle meningeal a (br external carotid a)* dura Subdural: a potential “space” (fluid-filled subarachnoid abuts against it) arachnoid FYI: arachnoid trabecula

pia

Subarachnoid space (actual space) Contents 1, e.g., cerebrospinal fluid (CSF) Contents 2: most of the extent of major brain aa Contents 3: most of the extent of major brain vv Brain (also spinal cord, optic n & olfactory n) *Rupture of middle meningeal a: epidural hematoma 27

Division of Anatomy EVMS

Epidural & Subdural potential spaces Epidural space superficial to dura mater

Brr of middle meningeal a

Anterior

Lateral view of brain w/ part of dura removed

Posterior Arachnoid mater (clear shinny membrane) over vessels/CSF, which are deep Wooden applicator in subdural space between dura & arachnoid

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Suture/seal after cranial surgery  Fascia lata from pt’s own thigh 



Fascia lata is deep fascia on lateral thigh

Sutures + “Dura Seal” Synthetic dura  Bovine pericardial sac  2011 FDA advisory1 cautioning against certain



Cadaveric dura transplants  b/c of risk of fatal prion infection Creutzfeldt-Jakob Disease 

1 http://www.fda.gov/MedicalDevices/Safety/AlertsandNo

http://medgadget.com/2005/04/duraseal.htm l

Dural repair

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jumps over sulci (valleys), unlike deeper pia mater, which adheres to brain and penetrates sulci

FYI gyri

Division of Anatomy. EVMS

FY I

Po st ce ntr al gy rus

FYI Pre -

central g

yrus

Blue pin through arachnoid mater. Note how the arachnoid

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Meninges: 3 Differences between Cord/Brain vertebrae 1. Unlike Brain: Actual epidural space exists with cord 2. Unlike Brain: Contains fat & internal vertebral venous plexus dura arachnoid Subarachnoid space (actual space) FYI: arachnoid trabecula

pia

Spinal Cord

3. Unlike Brain: Subdural space is NOT clinically relevant in cord 31

Dural tears & basilar skull Fx

Clinical correlates

Trauma- (or surgically) induced torn dura/arachnoid  CSF rhinorrhea 

CSF (clear fluid) leaks out of nose  Following Head injury via: Basal skull Fx of cribriform plate of ethmoid anterior cranial fossa) 



(i.e., Fx of base of

CSF otorrhea CSF leaks out of ear  Following head injury via  Basal skull Fx of petrous part temporal bone  Ruptured ear drum also needed for CSF to leak out of ear 

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3 Dural reflections #1. Falx cerebri: ÷ R/L cerebral hemispheres drops down from cranial dura like a curtain

Anterior attachment of falx cerebri: crista galli of ethmoid bone not seen

In addition to lining the bones of the cranial vault, there are sheets of dura that reflect away from the bone & follow contours of brain FYI. Falx cerebelli: vertically oriented fold ÷ R/L lobes of cerebellum

Plate 97, Netter

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From, e.g., top of petrous portion of temporal bone and A/P clinoid processes

Superior view of cranial vault #3. Diaphragma sellae: separates pituitary from brain

Modified from Plate 98, Netter 1997

3 Folds of dura, cont.

#2. Tentorium cerebelli: makes a tent above cerebellum to separate it from cortex To falx cerebri, cut here

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clivus

pituitary

“Superior” view of cranial vault w/ orbital portion of frontal bone removed to show eye

EVMS Division of Anatomy photo

“diaphragm of the saddle”

Crista galli

Diaphragma sellae

eye line: Dotted eye Diaphragma sellae separating pituitary Middlefrom brain cranial fossa

cord

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Div. Anatomy EVMS

Other views

Falx cerebri

cerebellum

Tentorium cerebelli

Hemisected head

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Falx cerebri and tentorium cerebelli

Falx cerebri Tentorium cerebelli running “down hill”

Division of Anatomy EVMS

Brain cut away at brainstem

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Outline: Cranial Vault & Dura Scalp  Cranial nerve openings  Dura mater  Dural sinuses  Internal carotid, vertebral & middle meningeal aa 

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Dural sinuses 

There are 2 layers of dura Periosteal layer (superficial; against bone)  Meningeal layer (deeper) 



Dural sinus

Layers split to form dural sinuses A dural sinus is, therefore, a tube of dura



2 Functions of Dural sinuses: Drain venous blood from brain -To internal jugular vv FYI: R is bigger than L  Drain cerebral spinal fluid from brain 

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6 Selected dural sinuses Superior sagittal sinus  Inferior sagittal sinus  Straight sinus  Transverse sinus  Sigmoid sinus  Cavernous sinus 

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Dural sinuses Superior sagittal sinus; in upper part of falx cerebri

Falx cerebri

Straight sinus; in medial part of tentorium cerebelli Confluence of sinuses

Plate 97, Netter

Inferior sagittal sinus; in lower part of falx cerebri

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Dural sinuses, cont.

Cavernous sinus -near pituitary gland FYI: superior petrosal sinus: top of petrous ridge

FYI: inferior petrosal sinus: bottom posterior face petrous ridge

Straight sinus in tentorium cerebelli

Sigmoid sinus: find indentation in occipital bone of dry skull Transverse sinus: find indentation in occipital bone of Confluence dry skull; in of sinuses tentor. cerebelli

Modified from Plate 98, Netter

pituitary

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Orange arrow: jugular foramen for IJV

Div. Of anatomy. EVMS

Indentations: transverse & sigmoid sinuses

Black arrow: sigmoid sinus

Blue arrow: transverse sinus 43

Division of Anatomy EVMS

Posterior view of brain Green wire traveling in opened superior sagittal sinus on top of falx cerebri

General area of the confluence of sinuses

Occipital sinus deep

Green wire continuing into opened transverse sinus within tentorium cerebelli 44

Dural sinuses & internal jugular v posterior view

Div. of Anatomy, EVMS

Superior sagittal sinus

Confluence of sinuses

Transverse Sinus

Sigmoid Sinus

angiogram Internal jugular v 45

Cavernous sinus -near pituitary gland

In the wall of the C 51 52 sinus: CN III, IV, 34 V1 & V2 “O TOM” 6

`

Within the sinus itself; the int. carotid artery and CN VI. “CA” plus sympathetics on the ICA “S.”

The unusual instance of an artery inside a venous system

Modified from Plate 98, Netter

Cavernous sinus: 3, 4, 51,52,6, int carotid a., & post. ganglionic. SNS on ICA “count” or say “O TOM CAS”

“O TOM CAS” 46

Cavernous sinus: Internal carotid a & CN’s 3,4,51,52,6 “count” Superior view of the middle cranial fossa

Orange: V2 heading for foramen rotundum

Sella turcica

Q: A cavernous sinus thrombus would have what affect on eye movement? A: Paralyze all eye movement: III, IV & VI

clivus

Box: Carotid sinus

Cavernous sinus also has ophthalmic vv draining into it from orbit

Division of Anatomy EVMS

Stick: sup orbital fissure w/ III, IV, V1, VI

Pipe cleaner: internal carotid a w/ post. gang. SNS fibers from sup cerv gang

Clinical correlate 47

ICA*

ICA*

white box

III

III not seen-IV V1/2 VI

VI

V

Green wires entering sinus w/ CN III Superior view of the base of the cranial vault

*ICA exiting sinus w/ SNS fibers cord Posterior fossa

Black circle: hypophyseal fossa

Div. Of anatomy. EVMS

Middle fossa

clivus

Cavernous sinus

II

II

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Basilar venous plexus

Interconnects various sinuses Also interconnects w/ internal vertebral venous plexus of spine

Clinical correlates

Allows spread of metastases & infections between brain/spine/trunk

Modified from Plate 98, Netter

Sits on clivus

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Epidural fat posterior

Plate 173 bottom left. Netter 2006

Internal vertebral venous plexus allows malignancy/ infection spread between trunk/spine/brain

Dura mater

anterior Internal vertebral venous plexus (of Batson): in cord epidural Epidural fat space

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Outline: Cranial Vault & Dura Scalp  Cranial nerve openings  Dura mater  Dural sinuses  Internal carotid, vertebral & middle meningeal aa 

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Brain: Blood Supply 

Internal carotid a Br common carotid a  Most strokes

1st ascending br subclavian a  Travel through: -transverse foramina of 1st 6 cerv vert & through FYI External carotid a -foramen magnum FYI Common carotid aa -make basilar a 

Fig. 10.2, p. 369, Blumenfeld. Neuroanatomy Through Clinical Cases. Sinauer, 2002

FYI Arch of aorta

FYI L. subclavian a

Vertebral aa

Vertebral-basilar system



Internal carotid a



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Internal carotid artery (red): segments

Cerebral seg Cavernous seg. Petrous seg. That part inside carotid canal, which is in petrous part of temp bone

That part inside cavernous sinus

Cervical seg. That part in the neck. NO brr in neck Grant’s Atlas 2005 Fig. 7.23B p. 621

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Slide 4

Internal carotid artery segments. AP MRA (magnetic resonance angiogram).

Cerebral seg. Cavernous seg. Petrous seg. Cervical seg.

Does not “capture” stationary tissue Klioze SD. The Brain. Dept. of Anatomy & Neurobiology & Dept. Radiology, EVMS 54

Vertebral aa III

III V

VII VI VIII IX X XI

clivus

V

Posterior view of clivus

VI

XII

Div. Of anatomy. EVMS

dotted lines

Vertebral aa (reflected inferiorly) as they enter foramen magnum

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Slide 4

ICA

ICA

Basilar a

Vertebral aa

Vertebral artery. AP MRA (magnetic resonance angiogram) Does not “capture” stationary tissue Klioze SD. The Brain. Dept. of Anatomy & Neurobiology & Dept. Radiology, EVMS

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Middle meningeal a Clinical correlate

Q: A Fx of the pterion will rupture what a. & cause what kind of bleed?  A: ant. br middle meningeal a; epidural bleed

Medial view Anterior br of middle meningeal artery is deep to Pterion “H” encircled in black



Posterior br of middle meningeal a

Middle meningeal a Maxillary a External carotid a

FYI. A/P brr sometimes called Grant’s Atlas 2005 Fig. 7.12A p. 609 Frontal/Parietal brr57

Craniotomy & Cranioplasty 

Craniotomy: temporary removal of a bone flap Epidural Video http://www.youtube.com/watch?v=dLMCwGmWvrw&feature=related  Store bone flap in abdominal subcutaneous space or  Store under the epicranial aponeurosis see next slide or  Freeze & store at a bone bank 



Cranioplasty: repair of damaged skull Replace bone flap or use  Plastic implant 

http://www.unifesp.br/dneuro/neu rociencias/229_revisao.pdf

http://www.medscape.com/viewarticle/472974_458

Middle meningeal a Enters cranial vault via foramen spinosum in greater wing of sphenoid

Foramen ovale

Pe tem trou p b s pa on rt Foramen e

Indentation made by post br of middle meningeal a

magnum

Basilar skull

Posterior

Div. Anatomy, EVMS

Anterior

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Cranial Vault & Dura

Objectives: Concept map: The organization of the scalp and its danger zone.  Blood supply to the scalp  Openings for the cranial nerves  Dura mater & its reflections in the cranial vault  Dural sinuses & the venous drainage of the brain  Internal carotid, vertebral & middle meningeal aa 

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