Part 71

The vena lingualis et hyoidea (Fig. 62, No. B, 7) collects the blood from the muscles of the tongue region, the lower tongue glands, and the upper throat region.

Between the two trunks of the vena facialis communis and anterior to the entrance of the vena cephalica posterior there is an anastomosis, the vena transversus (Fig. 62, No. B, 5). Through this anastomosis which lies crosswise the two jugular veins are influenced in different ways. At this point both jugular veins are of the same size. The anastomotic branch lies crosswise. Through this anastomosis the right receives some blood from the left head region indicating that the blood flows from left to right. This, as stated before, makes the left jugular vein the smaller.

BRANCHES OF THE VENA CEPHALICA POSTERIOR

The left vena cephalica posterior (Fig. 62, No. B, 8) communicates with the transverse vein (Fig. 62, No. B, 5). The left receives the smaller veins of the skin region, the esophagus, and the trachea. These vessels communicate with their fellow of the opposite side and with the vertebral vein of the same side, which causes a gradual reduction of the size of the jugular vein.

BRANCHES OF THE VENA OCCIPITALIS EXTERNUS

( ( Venæ choroideæ ( Sinus ( Venæ cutaneæ et frontales ( longitudinalis ( Venæ nasales Vena ( ( Venæ ophthalmiæ occipitalis ( externus ( ( ( Sinus occipitalis ( Sinus ( Sinus ( Sinus temporo-sphenoideus ( semicircularis ( transversus ( Venæ cerebellares ( ( ( Sinus petrosus sphenoideus

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.

The =sinus temporo-sphenoideus= (Fig. 62, No. A, 5) extends forward and outward from the transverse sinus, and, between the corpus quadrigeminum and the cerebrum, unites with the sinus venosus annularis basilaris.

The =sinus venosus annularis basilaris= lies in the region of the optic nerve and surrounds the hypophysis, forming a complete circle. It receives small vessels from the cerebrum, the corpora quadrigemina, and anteriorly the longitudinal basilar vein or vena basilaris media, of the cerebrum, which comes out of the anterior annular venous sinus. The anterior annular venous sinus surrounds the base of the olfactory nerves. It communicates with the sinus petrosus sphenoideus, which emerges from behind the optic lobe, the sinus temporo-sphenoideus, which emerges from in front of the optic lobe, and posteriorly the median longitudinal vein of the medulla oblongata or vena basilaris. Laterally and anterior to the optic lobe it receives the vena basilaris lateralis, and also a branch of the vena ophthalmica.

The blood received by the =sinus annularis basilaris= comes from the brain cavity through three pairs of veins, as follows: first, the two ophthalmic veins which pass through the posterior orbital wall between the olfactory and the optic nerve; second, two other branches of the ophthalmica which pass with the optic nerve; third, two veins which pass through a foramen by the side of the sella turcica to the hypophysis together with the carotis cerebralis, and then leave the cerebral cavity ventrally, at which point they are called the venæ carotes. These last accompany the cerebral artery backward, and pass through a foramen in the base of the cranium. Each one then passes through the cranial wall close to the external auditory canal, and empties into another vein in the posterior region of the head.

The =sinus fovæ hemispherii cerebelli= lies in the hollow between the os petrosum and the semicircular canals. It receives blood from the external occipital sinus and from the cerebellum, and empties into the vena auris interna.

VEINS OF THE BRAIN CAVITY

The =vena auris interna= passes through a bony canal along the outer rim of the posterior semicircular canal and then along the external semicircular canal. It receives vessels from the labyrinth, and extends along the posterior rim of the tympanum to the outer ear canal.

The =vena occipitalis interna=, extending from the sinus foraminis occipitalis, passes through the side of the atlas and divides near the condyle into two branches. One of these branches the internal occipital, forms the root of the vena vertebralis, and the other empties into the vena occipitalis externa.

Near the outer and upper part of the condyle it forms two large veins and collects the blood from the vena occipitalis media. These veins collect the blood from the rectus capitis anticus, and communicate with the vena cephalica anterior.

The =vena occipitalis externa=, sometimes called the vena occipitalis collateralis, extends from the vena auris, and receives vessels from the neck region. It receives on the side of the occipitoatloid joint the vena occipitalis interna. The vena occipitalis externa forms a junction with the vena vertebralis emptying into the transverse vein.

THE VEINS OF THE NECK

BRANCHES OF THE VENA JUGULARIS