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Home  »  Anatomy of the Human Body  »  pages 655

Henry Gray (1825–1861). Anatomy of the Human Body. 1918.

pages 655

fibrous bands (chordæ Willisii) extend transversely across the inferior angle of the sinus; and, lastly, small openings communicate with irregularly shaped venous spaces (venous lacunæ) in the dura mater near the sinus. There are usually three lacunæ on either side of the sinus: a small frontal, a large parietal, and an occipital, intermediate in size between the other two (Sargent 1). Most of the cerebral veins from the outer surface of the hemisphere open into these lacunæ, and numerous arachnoid granulations (Pacchionian bodies) project into them from below. The superior sagittal sinus receives the superior cerebral veins, veins from the diploë and dura mater, and, near the posterior extremity of the sagittal suture, veins from the pericranium, which pass through the parietal foramina.
  The numerous communications exist between this sinus and the veins of the nose, scalp, and diploë.


FIG. 567– Dura mater and its processes exposed by removing part of the right half of the skull, and the brain. (See enlarged image)
  The inferior sagittal sinus (sinus sagittalis inferior; inferior longitudinal sinus) (Fig. 567) is contained in the posterior half or two-thirds of the free margin of the falx cerebri. It is of a cylindrical form, increases in size as it passes backward, and ends in the straight sinus. It receives several veins from the falx cerebri, and occasionally a few from the medial surfaces of the hemispheres.
  The straight sinus (sinus rectus; tentorial sinus) (Figs. 567, 569) is situated at the line of junction of the falx cerebri with the tentorium cerebelli. It is triangular