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1. CRANIALCAVITY

3. Cranial Cavity
• The cranial cavity contains the
brain and its meninges,
cranial nerves, arteries, veins,
and venous sinuses
• The bones that take part in
formation of cranial cavity are
frontal, parietal, temporal,
occipital and ethmoid
1. Vault of the Skull
2. Base of the Skull

4. Vault of the Skull

5. Cranial Cavity
• The internal surface of cranial base has three
large depressions that lie at different levels:
the anterior, middle, and posterior cranial
fossae, which form the bowl-shaped floor of
the cranial cavity.
• The anterior cranial fossa is at the highest
level, and the posterior cranial fossa is at the
lowest level.

6. Cranial Cavity
1. Anterior cranial fossa which accommodates the
frontal lobe of brain.
2. Middle cranial fossa contain 2 temporal lobes of
brain.
3. Posterior cranial fossa accommodates occipital
lobes of the brain.
• The anterior cranial fossa is separated from
middle cranial fossa by lesser wing of sphenoid,
and the middle cranial fossa is separated from
the posterior cranial fossa by the petrous part of
the temporal bone.

7. Cranialcavityfloor
Middle cranial
fossa
Posterior
cranial fossa
Occipital bone
Jugular foramen
Foramen magnum
(spinal cord)
Anterior cranial fossa
View

8. Boundaries
Anteriorly and laterally Frontal bone
Floor: Orbital plate of frontal bone, cribriform plate of
ethmiod, anterior border of sphenoid’s lesser wings
Posteriorly :Posterior border of lesser wing of sphenoid,
anterior clinoid process and sulcus chiasmaticus.
Crista galli a sharp upward projection of ethmoid bone in
the midline, for the attachment of falx cerebri.
Foramen cecum Small aperture between the crista galli and
the frontal crest
Anterior cranial fossa

9. Frontal bone
Olfactory foramina
Cribriform plate
Ethmoid
bone Crista galli
Anterior cranial fossa
View

10. Figure7.2c Theskull:Cranialandfacialdivisionsandfossae.
Frontal lobe
of cerebrum
Temporal lobe
of cerebrum
Cerebellum
Posterior
Middle
Anterior
Cranial
fossae
(c) Lateral view of cranial fossae showing the
contained brain regions

11. Middle cranial fossa
Boundaries
Anteriorly Post border of the lesser wings of sphenoid,
anterior clinoid processes and sulcus chiasmaticus.
Posteriorly Superior borders of petrous part of
temporal and dorsum sella of sphenoid.
Laterally Squamous part of temporal and some part of
parietal and greater wings of sphenoid.
Floor Greater wing of sphenoid and petrous and
squamous parts of the temporal bone.
In the centre, floor is formed by the sella turcica of
body of sphenoid.

12. Hypophyseal fossa
of sella turcica
Middle cranial
fossa
Superior view of cranial interior
Frontal bone
Optic canal (cn 2)
Sphenoid Lesser wing
Greater wing
View

13. Middle cranial fossa
• The sella turcica ( Turkish saddle) is the saddle-
like bony formation on the upper surface of the
body of sphenoid, which is surrounded by the
anterior and posterior clinoid processes.
• Clinoid means “bedpost, and the four processes
(two anterior and two posterior) surround the
hypophysial fossa, the “bed” of the pituitary
gland, like the posts of a four-poster bed. The
sella turcica is composed of three parts:

14. Middle cranial fossa
• The tuberculum sellae (horn of saddle): prominent
median elevation forming the posterior boundary of
the prechiasmatic sulcus and the anterior boundary of
the hypophysial fossa.
• The hypophysial fossa (pituitary fossa): a median
depression (seat of saddle) in the body of the
sphenoid that accommodates the pituitary gland.
• The dorsum sellae (back of saddle): a square plate
of bone projecting superiorly from the body of the
sphenoid. It forms the posterior boundary of the sella
turcica, and its prominent superolateral angles make
up the posterior clinoid processes.

15. Middle cranial fossa
• On each side of the body of the sphenoid, a crescent
of four foramina perforate surfaces of the greater
wings of sphenoids structures transmitted by
foramina.
• Superior orbital fissure: Located between the
greater and the lesser wings, it opens anteriorly into
the orbit.
• Foramen rotundum (round foramen): Located
posterior to the medial end of the superior orbital
fissure opens into pterygopalatine fossa.

16. Middle cranial fossa
• Foramen ovale (oval foramen): A large foramen
posterolateral to the foramen rotundum, it opens
inferiorly into the infratemporal fossa
• Foramen spinosum (spinous foramen): Located
posterolateral to the foramen ovale, it also opens
into the infratemporal fossa in relationship to the
spine of the sphenoid.
• The foramen lacerum ragged foramen lies
posterolateral to the hypophysial fossa and is an
artifact of a dried cranium. In life, it is closed by
a cartilage plate

17. Posterior cranial fossa
Boundaries
Anteriorly
Superior border of the petrous part of temporal
bone and dorsum sallae.
Posteriorly
Internal surface of squamous part of the
occipital bone.
Floor
Basilar, squamous & condylar parts of the
occipital bone & mastoid part
foramen magnum forms the central part of the
floor.

18. Hypophyseal fossa
of sella turcica
Middle cranial
fossa
Temporal bone
Posterior
cranial fossa
Parietal bone
Occipital bone
Frontal bone
Olfactory foramina
Optic canal
Cribriform plate
Ethmoid
bone Crista galli
Sphenoid
Anterior cranial fossa
Lesser wing
Greater wing
Hypoglossal canal
Foramen magnum
View

21. Cranial Cavity
• The cranial cavity contains
the brain and its meninges,
cranial nerves, arteries,
veins, and venous sinuses
• The bones that take part on
formation are frontal,
parietal, temporal, occipital
ethmoid
1. Vault of the Skull
2. Base of the Skull