3.2

Anatomy of the Dura Mater and the Cranial Nerves (Figs. 3.3, 3.4)

In most textbooks it is accepted that the CSs are located between the two layers of the dura mater: the periosteal (endosteal) layer forming the floor and most of the medial wall of the CS, and the dural layer forming its roof, lateral wall, and the upper part of the medial wall (Umansky and Nathan 1987).

According to Keller et al. (1997), only three surfaces are covered by dura mater: the superior, the lateral and the medial surface. The dura mater of the medial surface can be very thin or fenestrated.

The lower surface is covered by the periost of the floor of the middle cranial fossa. The roof of the CS is formed by the anterior extension of the tentorium and the lateral extension of the diaphragm sellae, while the lateral wall is formed by the dura propria of the middle cranial fossa.

Various concepts and contradictory descriptions of the lateral wall of the CS exist (Umansky and Nathan 1987). While most classical textbooks (Warwick and Williams 1973; Christensen and

Telford 1978) describe CNs III, IV and V1, V2 as being embedded in the lateral wall, others (Paturet 1964; Rouviere 1970) differentiate a deep and a superficial layer of the lateral wall, dividing the CS into two compartments by a “septum” and

6

Fig. 3.3. From Professior Elliot Smiths

“Textbook of Anatomy”, drawn from a

7dissection in the Moorfield Pathological

8

Museum

1 Infundibulum

92 Hypophysis

126 Intercavernous sinus

7 3rd cranial nerve (superior division)

138 3rd cranial nerve( inferior division)

9 Lesser sphenoid wing

1410 Trochlear nerve

11 Internal carotid artery

12 1st division, 5th cranial nerve

13 6th cranial nerve

14 2nd division, 5th cranial nerve

15 Sphenoid sinus

16 Cavernous sinus