Veins of the Head. 



441 



Sinus cavernosus 



A. carotis interna 



Hypo- 

 physis 



Sinus 



inter- 



cavernosus 



posterior 



Corpus ossis 

 splienoidalis 



Sinus 

 splienoidalis 

 (cut through) 



N. oculo- 

 motorius 



N. 

 trochlearis 



N. 

 abducens 



N. oph- 

 ~ thalmicus 



N. maxil- 

 laris 



482. Frontal section through the right sinus 



cavernosus, viewed from behind. Magnification 5:2. 



The sillUS dlirae lliatris (sinuses of the dura mater) are venous canals which run, 

 chiefly, between the separated hiyers of the dura mater and lie at the same time in corresponding 

 hony grooves. They stand open on section and are devoid of valves ; the sinus sagittalis superior 

 and cavernosus are crossed in a network-like manner by bands of connective tissue. They receive 

 the vv. cerebri, meningeae, diploicae (partially), mulitivae internae and the vv. ophihalmicae . 



1. Sinus trausrersus (0. T. lateral sinus) (see Figs. 483 and 484), paired, collects 

 most of the blood from the skull cavity. It begins on each side at the protuberantia occipitalis 

 interna, communicating with that of the other side by an opening of variable size ; it is usually 

 larger on the right than on the left side and runs curved lateralward in the sulcus transversus 

 of the occipital bone and of the parietal bone, in the attached margin of the tentorium cere- 

 belU. Thence, it goes tortuous medianward and downward, in the sulcus sigmoideus of the 

 temporal bone and in the sulcus transversus of the pars lateralis oss. occiptalis, to the foramen 

 jugulare to become continuous there with the upper end of the v. jngularis interna. In the 

 region of the tentorium cerebelli it is triangular-prismatic in shape, elsewhere semi-cylmdrical. 



2. Sinus sagittalis superior (0. T. superior longitudinal sinus) (see Figs. 483 and 484), 

 unpaired, extends from before backward, in a curve, in tht> attached margin of the falx cerebri 

 near the crista frontahs and in the sulcus sagittalis of the frontal bone, of the parietal bones 

 and of the occipital bone and opens into the sinus transversus (usually into the xight). It is 

 triangular in transverse section. The sinus anastomoses with the following. 



3. Sinus sag'ittalis inferior (0. T. inferior longitudinal sinus) (see Figs. 483 and 484), 

 unpaired, from before backward in the free margin of the falx cerebri into the sinus rectus. 



4. Sinus rectus (straight sinus) (see Figs. 483 and 484), unpaired, goes as a triangular 

 canal, at the point of attachment of the falx cerebri to the tentorium cerebelli, ffom in front 

 and above, backward and downward and opens into the sinus transversus (usually into the left). 



'5. Sinus occipitalis (see Figs. 483 and 484), unpaired or paired, begins at the pro- 

 tuberantia occipitalis interna and goes downward, close to the median plane, in the attached 

 margin of the feLx cerebelli. Above, it begms at the spot where the sinus transversi, the sinus 

 sagittalis superior and the sinus rectus meet (confluens simmrn). Below, it bifurcates, turns 

 lateralward and forward on both sides above the foramen occipitale magmmi and enters the 

 sinus transversus, close to the foramen jugulare. It anastomoses with the plexus venosi verte- 

 brales interni and varies much in the degree of its development. 



6. Sinus cavernosus (see also Figs. 442, 483 and 484), paired, is an irregular space, 

 which is situated, on each side, near the sella turcica and the corpus oss. sphenoidalis. It is 

 bounded above and lateralward by that part of the dura mater which is stretched out between 

 the proc. clinoidens anterior and the dorsum sellae and the apex of the pyramis oss. ternporalis 

 and goes over into the tentorium cerebelli; it surrounds, in addition, the a. carotis interna, 

 the n. abducens and the plexus caroticus internus. Tributaries: 



