Sinus petrosus sphenoideus ( Retis mirabile temporalis Sinus temporo-sphenoideus ( Sinus annularis venosus basilaris Sinus foraminus occipitalis ( Venæ medullares ( Venæ cerebrales Sinus ( Vena cerebralis basilaris ( Sinus venosus annularis anterior venosus ( annularis ( basilaris ( Vena ophthalmica ( Vena medullaris mediana longitudinalis The vena cephalica posterior (Fig. 62, No. _B_, 8) is formed from the veins of the sinuses of the cranium, the brain, the vena auris, the vena jugularis prima, the vena carotis, and the vena occipitalis. It collects most of the blood from the cranium and the posterior part of the head and from the tongue. THE VENOUS SINUSES OF THE HEAD The =sinus longitudinalis= (Fig. 62, _A_, 10) extends from the dorsal median line of the internal occipital protuberance to the olfactory nerve. It collects the blood from the choroidea of the brain and from the skin of the frontal region. It receives laterally the veins of the nose, the vena ophthalmica, and the sinus transversus. The =sinus occipitalis= (Fig. 62, No. _A_, 4) forms the continuation of the transverse sinus. It is located in the posterior cerebral cavity, and is wing-shaped, extending both to the right and to the left. The =sinus foraminis occipitalis= a continuation of the sinus occipitalis, lies transversely on the ventral side of the cranial cavity and receives the veins from the medulla oblongata. One branch passes through the os occipitalis basilare, and then extends sidewise to the foramen magnum and anastomoses with the vena occipitalis. The =sinus transversus= (Fig. 62, No. _A_, 6) extends in a pair from the internal occipital protuberance between the cerebrum, cerebellum, and the corpus quadrigeminum. It receives vessels from the upper surface of the cerebellum. The sinus has three branches, all of which empty into the sinus semicircularis. The =sinus semicircularis= extends along the dorsal petrosal rim, anterior to the inner ear, and from this point backward. Near the foramen magnum it passes through the os occipitale and empties into the external occipital vein. The =vena occipitalis externus= extends near the foramen magnum, surrounds the basis occipitalis, and receives the semicircular sinus and through the semicircular sinus the blood from the sinus transversus. The =sinus petrosus sphenoideus=, passing in company with the occipital sinus, extends from the transverse sinus to the cavity near which the trigeminus lies. The sinus dividing into two branches, one of these extends to the hypophysis and unites with the basal veins of the brain; the other passes with the rete out of the cranial cavity along with a branch of the trigeminus, and communicates with the rete mirabile temporale.