Download Skull Base Anatomy Review

Surgical Anatomy of
Skull Base
Dr. Supreet Singh Nayyar, AFMC
www.nayyarENT.com
1
Topography of Skull Base
Boundaries :
Anterior : Incisors upper teeth
Posterior: Superior nuchal line
Lateral
: Upper lateral teeth
Zygomatic arch
Mastoid process
www.nayyarENT.com
2
Topography of Skull Base
Anterior Skull Base
Central Skull Base
Posterior Skull Base
www.nayyarENT.com
3
Skull Base Anatomy Review
Key Openings
• Foramen spinosum
• Superior orbital fissure
• Foramen ovale
• Inferior orbital fissure
• Foramen lacerum
• Optic canal
• Foramen rotundum
• Vidian canal
• Foramen magnum
• Hypoglossal canal
• Foramen of vesalius
• Pterygopalatine fossa
• Jugular foramen
www.nayyarENT.com
4
Skull Base Anatomy Review
Foramen magnum
Hypoglossal canal
• Medulla oblongata
• Hypoglossal nerve
• Vertebral arteries
• Hypoglossal artery
• Anterior/Posterior spinal
arteries
Jugular Foramen
• Pars nervosa: CN IX, inferior petrosal sinus
• Pars vascularis: CN X, XI, jugular bulb
www.nayyarENT.com
5
Skull Base Anatomy Review
Foramen Spinosum
• Middle meningeal artery
• Recurrent branch of
mandibular nerve
Foramen of Vesalius
• Sphenoidal Emissary vein
Foramen Ovale
Stylomastoid foramen
• Mandibular nerve
• Accessory meningeal artery
• Lesser petrosal nerve
•Facial nerve
•Stylomastoid artery
• Emissary veins
www.nayyarENT.com
6
Skull Base Anatomy Review
Foramen Lacerum
• Ascending pharyngeal artery- meningeal branch
• Nerve of pterygoid canal
Pterygoid canal
• Vidian nerve
• Vidian artery
Foramen rotundum
• Maxillary nerve
• Artery of foramen rotundum
• Emissary veins
www.nayyarENT.com
7
Skull Base Anatomy Review
Cavernous Sinus
Receives:
Superior opthalmic vein
Inferior opthalmic vein
Sphenoparietal sinus
Drains via:
Petrosal sinuses
Basilar plexus
Pterygoid plexus
Connection:
Circular sinus
Contains:
CN III, IV, V1, V2, VI
Meckel’s Cave
• Posterior aspect of cavernous sinus
• Gasserian ganglion (sensory root ganglion of
www.nayyarENT.com
CN V)
8
Skull Base Anatomy Review
Superior Orbital Fissure
• CN III, IV, V1, VI
• Middle meningeal artery- orbital branch
• Recurrent meningeal artery
• Superior ophthalmic vein
Inferior Orbital Fissure
• Infraorbital artery, vein, and nerve (V2 branch)
Optic Canal
• Optic nerve
• Ophthalmic artery
www.nayyarENT.com
9
Central Skull Base
www.nayyarENT.com
10
Central Skull Base
6
2
1
1
5
3
4
1- Pharyngeal Area
2- Tubal Area
3- Neurovascular Area
4- Auditory Area
5- Articular Area
6- Infratemporal Foss
www.nayyarENT.com
11
Pharyngeal Area


Roof of Nasopharynx
Boundaries of
Nasopharynx :
* Anterior
* Lateral & Posterior
* Inferior
www.nayyarENT.com
12
Pharyngeal Area


Pharyngobasilar fasia
Fossa of Rosenmullar
* Location- above &
behind medial end ET
* Depth- 2.5 cm
* Apex- Carotid canal
opening (post) &
f. ovale, f. spinosum
(lat)
* Base- below
Foramen lacerum
www.nayyarENT.com
13
Tubal Area
Eustachian Tube




Scaphoid fossa
Runs b/w petrous
bone & greater wing
sphenoid
Opening- nasopharynx
Paratubal muscles
www.nayyarENT.com
14
Neurovascular Area
Important structures are:

Carotid sheath & its contents

Styloid apparatus

Facial Nerve
www.nayyarENT.com
15
Carotid Sheath

Compact network of aerolar tissue

Carotid canal to arch of aorta



Encloses : ICA above & CCA below
IJV
Vagus nerve
Carotid Canal : ICA & Carotid plexus
sympathetic nerve
Parts of ICA
www.nayyarENT.com
16
Jugular Foramen
Divided into three compartments
Compartments
Contents ( lateral
to medial )
Anterior
* IX Nerve
* Inferior petrosal
Sinus
Middle
* XI Nerve
* X Nerve
* IJV
Posterior
www.nayyarENT.com
17
Styloid Apparatus



Bone- Styloid bone
Ligaments- * Stylohyoid
* Stylomandibular
Muscles- * Stylohoid
* Stylopharyngeus
* Styloglossus
www.nayyarENT.com
18
Facial Nerve


Arise from Stylomastoid Foramen
Branches:
i) Post auricular nerve
ii) Digastric branch
iii) Temporofacial branch
iv) Cervicofacial branch
www.nayyarENT.com
19
Auditory Area

Petrotympanic
fissure of Glaser:
* Chorda tympani
* Ant br of
tympanic artery
www.nayyarENT.com
20
Infratemporal Fossa



Location : below middle
cranial fossa
Boundaries
Contents:
* Med & Lat Pterygoid M
* Maxillary A
* Maxillary V
* Pterygoid Venous Plexus
* Br of Mandibular N www.nayyarENT.com
21
Pterygopalatine Fossa

Small inverted pyramid shaped fossa

Location

Boundaries

Communications
www.nayyarENT.com
22
Anterior Cranial Base
www.nayyarENT.com
23
Anterior Cranial Base from inside
www.nayyarENT.com
24
Floor of Anterior Cranial Fossa

Depth of Olfactory
fossa (Keros classification)
* Type I – 1-3mm
* Type II- 4-7mm
* Type III- 8-17mm
www.nayyarENT.com
25