Skull Base Surgery of the Posterior Fossa

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Fig. 1.1 Posterior fossa osseous and dural enclosure. (a)
Superior view of the skull base. The posterior fossa is
enclosed by the sphenoid, temporal, and occipital bones.
The bony imprints of the major venous structures can be
seen. (b) Medial view of the lateral bony wall of the pos-
terior fossa. Sulci for venous sinuses encircling the medial
face of the temporal bone are seen. The hypoglossal canal
is bordered superiorly by the jugular tubercle, and the
suprameatal tubercle is anterior and superior to the inter-
nal auditory canal (IAC). (c) Superior view of the poste-
rior fossa dura. The dural lining of the posterior fossa
invaginates into the neural foramina and forms venous
channels between its layers. (d) Medial view of petrous
temporal bone with internal structures exposed. The

cochlea is located above the genu of the petrous carotid

artery, and the semicircular canals are superior to the jug-

ular bulb. The trigeminal nerve courses above the trigemi-

nal depression of the petrous bone to enter Meckel’s cave.

(e) Superior view of the tentorium attachments. The tento-

rium is anchored to the petrous ridge at the superior petro-

sal sinus and to the occipital bone at the transverse sinus

and torcula. (f) Right superior oblique view of the tento-

rium. The midbrain is continuous with the thalamus

through the tentorial incisura. Anteriorly, the tentorium

extends as the anterior and posterior petroclinoid folds

which insert on the anterior and posterior clinoid pro-

cesses. The oculomotor nerve enters the roof of the cav-

ernous sinus between these folds

1 Surgical Anatomy of the Posterior Fossa