Anatomy Skull And Pituitary Fossa

Front 1

3 fossas of endocranium

Back 1

Anterior
Middle
Posterior

Front 2

Boney landmarks of skull

Back 2

Front 3

Clinoid

Back 3

means bed
- anterior clinoid above the optic canal

Front 4

Between the anterior and middle fossa

Back 4

- lesser wing of sphenoid
- anterior clinoid

Front 5

Between the posterior and middle fossa

Back 5

laterally; superior ridge of petrous portion of temporal bones
anteriorly: dorsum sellae

sella: Latin = saddle; adjective - sellar, sella turcica = Turkish saddle.

Front 6

Contents of anterior cranial fossa

Back 6

• Cristae galli: an expansion of the ethmoid bone/ it attaches the anterior aspect of the falx (dura)
• Cribriform plate: penetration of the olfactory nerve
• Ethmoidal foraminae: anterior and posterior ethmoidal nerves
• Orbital plate of the FRONTAL BONE

Front 7

Cristae galli

Back 7

crista: Latin = crest, crista galli = the (median) crest of a cock.

Front 8

Contents of The Posterior Cranial Fossa

Back 8

• Foramen magnum: most inferior portion of the p.c.f
• Hypoglossal canal: exit of the hypoglossal nerve (nXII)
• Jugular foramen: exit of vagus (nX),glossopharyngeal (nIX), and accessory (nXI) nerves.
• Internal auditory meatus: exit of facial (nVII) and
vestibulocochlear (nVIII) nerves.
• Clivus: basilar portion of the occipital bone and the body of the sphenoid.
• Internal occipital crest: attaches the posterior portion of the falx.

Front 9

Clivus

Back 9

clivus: Latin = slope (cf. declivity)

Front 10

Jubular vein formed from

Back 10

Front 11

Contents of the middle cranial fossa

Back 11

• 4 clinoid processes: a “bed”
• Optic canal and associated groove:
• The Sella Turcica: the “turkish saddle”.
• Foramen lacerum: encompasses the apertures of
the carotid canal and the pterygoid canal > passing
into the foramen is the greater petrosal nerve
(derived from the facial nerve (nVII) which then
enters the pterygopalatine fossa.
• Superior orbital fissure: exit of the ophthalmic division ofthe trigeminal nerve (nVi), oculomotor (nIII), trochlear
(nIV) and abducens (nVI) nerves. It is formed from the
greater and lesser wings of the sphenoid bone, it enters the
orbital cavity.
• Foramen rotudum: exit of the maxilliary division of thetrigeminal nerve (nVii) which enters the pterygopalatine
fossa
• Foramen ovale: exit of the mandibular division of the
trigeminal nerve (nViii) and also the lesser petrosal nerve
(parasympathetic fibres to otic ganglion). It enters the
infratemporal fossa.
• Foramen spinosa: exit of the middle meningeal artery, alsoexits in to the infra

Front 12

The anterior surface of the petrous portion of the
temporal bone has

Back 12

(i) a depression for the
trigeminal ganglion, has (ii) an arcuate eminence
(elevation over the anterior portion of the
semicircular canals), (iii) foramina and grooves for
the greater and lesser petrosal nerves.
Yet another aside…….
the squamous portion of the temporal bone has a
groove for the middle meningeal artery

Front 13

Cavernous Sinus
- contents

Back 13

The cavernous sinus lies between 2 layers of
dura (ie the dura is split)
Lying BETWEEN these layers
(i) Trigeminal nerve (Vi) (possibly a bit of Vii)
(ii)Oculomotor n., Trochlear n., Abducens n.
(iii) Internal carotid
(iv) Sympathetic plexii

Lying OUTSIDE BOTH these layers
(i) Middle meningeal artery
(ii)Petrosal nerves (parasympathetics)
Lying INSIDE BOTH these layers
(i) Optic chiasm, Optic n.,
(ii) Pituitary gland
(iii) Temporal lobe of cortex

Front 14

Cavernous Sinus
- drains

Back 14

- opthalmic vein
- temporal and pituitary

Front 15

BS to to trigeminal ganglia

Back 15

Twigs of the internal carotid “feed” the
trigeminal ganglion………….what happens if
blood supply interrupted ???
can completely switch off the trigemenial ganglion
- can get positive sensory signs then -ve signs (Ipsilateral)

Front 16

cavernous Sinus near exit of the S>O>F

Back 16

Front 17

Greater Petrosal nerves

Back 17

• A branch of the FACIAL nerve, travels below the trigeminal ganglion
• Exits via the foramen lacerum
• Travels through the pterygoid canal into the pterygopalatine fossa
• Synapses on pterygopalatine ganglion, supplies lacrimal, nasal and palatine glands (tears, mucus, saliva).

from the posterior cranial fossa
- IAM small branch comes off and gets through petrous temporal bone to get to anterior surface and breaks through to get to middle cranial fossa, travels medial to fopreamen lacrum and then to pterygoid canal, trying to find its ganglion pterygoplaalatine fossa
- ganglion to supply lacrimal and nasal and palatine glands...

Front 18

Lesser Petrosal nerve:

Back 18

• A branch of the GLOSSOPHARYNGEAL nerve, travels lateral to the greater petrosal nerve.
• Exits via the foramen ovale
• Synapses on otic ganglion, supplies parotid gland, via auriculotemporal nerve (saliva).