7. Anterior Skull Base (frontal & ethmoid) Central Skull Base (sphenoid & temporal) Posterior Skull Base (temporal, parietal & occipital)

8. FrontalEthmoidMaxillaryZygomaticPalatineVomerSphenoidMandibleTemporalAtlasParietal Occipita l

9. FRONTAL BONE 1. Frontal crest 2. Foramen cecum 3. Digital impressions ETHMOID BONE 4. Crista galli 5. Cribiform plate SPHENOID BONE 6. Lesser wing 7. Greater wing 8. Anterior clinoid process 9. Clivus TEMPORAL BONE 10. Squamous portion 11. Arcuate eminence 12. Petrous ridge PARIETAL BONE OCCIPITAL BONE 13. Clivus 14. Occipital condyle 15. Internal occipital crest 16. Internal occipital protuberance 1 2 3 4 3 4 5 6 8 7 10 9/13 11 11 12 14 12 14 15 15 16 16

10. ANTERIOR SKULL BASE 1.Foramen cecum (small emissary vein to superior sagittal sinus) 2.Anterior ethmoid foramen (anterior ethmoid artery, vein, nerve) 3.Foramina of cribiform plate (afferent fibers to olfatory bulbs) 4.Posterior ethmoid foramen (posterior ethmoidal artery, vein, nerve) 5.Optic canal (optic artery and nerve) 1 2 3 4 5

11. CENTRAL SKULL BASE 1.Superior orbital fissure (III, IV, V1, VI CN, superior ophthalmic artery) 2.Foramen rotundum (V2 CN) 3.Foramen ovale (V3 CN, accesory meningeal branch, lesser petrosal nerve) 4.Foramen spinosum (middle meningeal artery and vein, meningeal branch of V3 CN) 5.Foramen lacerum 6.Carotid canal (internal carotid artery and sympathetic plexus) 7.Hiatus for greater petrosal nerve 1 1 2 3 5 4 5 4 6 7

12. POSTERIOR SKULL BASE 1.Internal acoustic meatus (VII, VIII CN, laberynthine artery) 2.Hypoglossal canal (XII CN) 3.Jugular foramen (inferior petrosal sinus, IX, X, XI CN, sigmoid sinus, posterior meningeal artery) 4.Foramen magnum (cephallad component of XI CN, medulla oblongatta, vertebral arteries) 1 2 3 2 3 4

13. 1.Foramen cecum 2.Crista galli 3.Cribiform plate 4.Optic canal 5.Anterior clinoid process 6.Sella turcica 7.Sphenoid sinus 8.Vomer 9.Posterior clinoid process 10.Mastoid foramen 11.Sigmoid plate 12.Internal acoustic meatus 13.Jugular foramen 14.Hypoglossal canal 15.Foramen magnum 16.Occipital condyle 1 10 9 5 4 2 10 9 5 4 2 11 6 3 11 6 3 12 12 13 7 13 7 14 8 14 8 15 16 15 16

14. ANTERIOR SKULL BASE (FROM BELOW) MAXILLAR BONE 1. Incisival canal 2. Palatine process 3. Median palatine suture 4. Zygomatic process PALATINE BONE 5. Horizontal plate 6. Greater palatine foramen 7. Pyramidal process 8. Posterior nasal spine SPHENOID BONE 9. Pterygoid process 10. Greater wing 1 2 4 2 4 3 5 7 6 7 6 8 10 9 10 9

15. POSTERIOR SKULL BASE (FROM BELOW) SPHENOID BONE 1. Foramen ovale 2. Foramen spinosum TEMPORAL BONE 3. Zygomatic process 4. Carotid canal 5. Foramen tympanicum 6. External acoustic meatus 7. Jugular fosae 8. Styloid proccess 9. Stylomastoid foramen 10. Mastoid process 11. Mastoid stria 12. Mastoid foramen OCCIPITAL BONE 13. Pharyngeal tuberble 14. Foramen magnum 15. Inferior nuchal line 16. External occipital crest 17. External occipital protuberance 18. Superior nuchal line 3 1 3 1 2 13 4 2 13 4 5 7 8 7 8 6 9 10 14 11 10 14 11 12 12 15 16 15 16 17 18 17

16. 1. FRONTAL BONE 2. ETHMOID BONE 3. NASAL BONE 4. LACRIMAL BONE 5. MAXILLAR BONE 6. PARIETAL BONE 7. SPHENOID BONE 8. TEMPORAL BONE 9. ZYGOMATIC BONE 10. MANDIBLE 1 6 7 4 2 7 4 2 7 3 8 3 8 5 9 5 9 10 10

17. 1. Supraorbital foramen 2. Anterior ethmoidal foramen 3. Posterior ethmoidal foramen 4. Lamina papyracea 5. Nasolacrimal fossa 6. Orbital process of palatine 7. Lesser wing of sphenoid 8. Superior orbital fissure 9. Optic canal 10. Greater wing of sphenoid 11. Inferior orbital fissure 12. Infraorbital foramen 1 2 7 2 7 3 8 3 8 4 9 10 4 9 10 5 6 5 6 11 11 12 12

18. 1. Arterial impressions 2. Mastoid foramen 3. Internal acoustic meatus 4. Jugular foramen 5. Hypoglossal canal 6. Optic canal 7. Superior orbital fissure 8. Foramen rotundum 9. Foramen lacerum 10. Foramen ovale 1 6 2 3 2 3 4 7 5 9 8 5 9 8 10 10

19. CRIBIFORM PLATE Afferent fibers to olfatory bulbs

20. OPTIC CANAL Optic Nerve Optic artery

21. ANT. & POST. CLINOID PROCESSES

22. CAROTID CANAL Internal carotid artery Sympathetic plexus

23. FORAMEN ROTUNDUM Maxillary nerve (CN V2)

24. FORAMEN OVALE Mandibular nerve (CN V3) Accesory meningeal branch of maxillary artery Lesser petrosal nerve

25. INTERNAL ACOUSTIC CANAL Facial nerve (CN VII) Vestibulocochlear nerve (CN VIII) Labyrinthine artery

26. CLIVUS

27. SIGMOID SINUS & JUGULAR FORAMEN Glossopharyngeal nerve ( CN IX) Vagus nerve (CN X) Accesory nerve (CN IX) Posterior meningeal artery

28. Click on the image Virtual tour to the skull base