THE SINUSES OF THE DURA 



729 



The superior petrosal sinus (sinus super petrosus, sinus petrosus superior} 

 (Figs. 503 and 507) is situated along the superior border of the petrous portion 

 of the temporal bone, in the front part of the attached margin of the tentorium 

 cerebelli. It is small and narrow, and connects the cavernous and lateral sinuses 

 at each side. It receives some cerebellar and inferior cerebral veins, and veins 

 from the tympanic cavity. 



The inferior petrosal Sinus (sinus subpetrosus, sinus petrosus inferior) (Figs. 

 503 and 508) is situated in the groove formed by the junction of the posterior 

 border of the petrous portion of the temporal with the basilar process of the 

 occipital bone. It commences in front at the termination of the cavernous sinus, 

 and passing through the anterior compartment of the jugular foramen, ends in 

 the commencement of the internal jugular vein" The inferior petrosal sinus 

 receives a vein from the internal ear (vv. auditivae internae) and also veins from 

 the medulla oblongata, pons, and under surface of the cerebellum. 



Falx cerebri 



Inferior 

 petrosal sinus 



Optic nerve 

 Int. carotid artery 



Oculomotor nerve 



Dorsum sellae 



Glossopharyngeal, 

 vagus, and spinal 

 accessory nerves. 



Lateral sinus 

 FIG. 508. Relation of nerves to sinuses in jugular foramen. (Henle.) 



The exact relation of the parts to one another in the foramen is as follows: The 

 inferior petrosal sinus is in front, with the meningeal branch of the ascending 

 pharyngeal artery, and is directed obliquely downward and backward; the lateral 

 sinus is situated at the back part of the foramen with a meningeal branch of the 

 occipital artery, and between the two are the glossopharyngeal, vagus, and spinal 

 accessory nerves (Fig. 508). These three sets of structures are divided from 

 each other by two processes of fibrous tissue. The junction of the inferior petrosal 

 sinus with the internal jugular vein takes place superficial to the nerves, so that 

 these latter lie a little internal to the venous channels in the foramen (Fig. 508). 



