A) Frontal bone (orbital part).
B) Lesser wing of the sphenoid bone.
C) Greater wing of the sphenoid bone.
D) Squama of the temporal bone.
E) Petrous portion of the temporal bone.
F) Mastoid process of the temporal bone.
G) Occipital part of 16216o1417q the occipital bone.
H) Basilar part of the occipital bone.
I) Lamina cribrosa of the ethmoid bone.
a) Cerebral ridge.
b) Digitate impressions.
c) Internal frontal spine, located in the longitudinal sulcus
and it is attached to the falx cerebri.
d) Crista galli is connected
to the falx cerebri.
e) Foramina cribrosa allowing passage of olfactoria nerve.
f) Anterior clinoid process.
g) Optic foramen for the passage of the optic nerve and ophthalmic artery.
h) Middle clinoid process.
i) Sella turcica, the fossa for the hypophysis gland.
k) Posterior clinoid process.
l) Carotid sulcus and exit of the carotid canal.
m) Superior orbital fissure (passage for ophthalmic vein, and nn oculomotor, trochlear, and abducens).
n) Foramen rotundum (for maxillary nerve).
o) Foramen ovale (for mandibular
nerve).
p) Foramen spinosum (for middle meningeal
artery, occasionally for the lesser superficial petrosal
nerve).
q) Canal or Hiatus for the greater petrosal nerve
(passage for the nerve of the pterygoid canal).
r) Internal auditory meatus (passage for acoustic
artery, vein, and nerve and the facial nerve).
s) Vestibular aqueduct.
t) Jugular foramen (passage for internal jugular vein, nn
glossopharyngeal, vagus,
and spinal accessory).
u) Fossa for the medulla oblongata.
v) Clinoid process.
w) Anterior condyloid foramen (passage for
hypoglossal nerve).
x) Posterior condyloid foramen (passage for Santorini emissary vein; often absent).
y) Mastoid foramen.
z) Foramen magnum (passage for medulla oblongata, accessory nerve, vertebral
artery and vein and spinal arteries).
a) Sigmoid fossa (a part of the transverse sulcus).
b) Internal occipital
spine (cruciate eminence).
g) Internal occipital
ridge (for the falx cerebelli).
d) Foramin
cecum.
e) Ephippium
with the clivus.
z) Foramen cecum.
h) Lingula.
q) Transverse sulcus.
i) Condyloid
process of the occipital bone.