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BLOOD-VESSEL SYSTEM OF THE HEAD, ETC. : 257
artery, and terminates by emptying into the internal jugular vein
slightly above the level of the cricoid cartilage.
The Vertebral Vein commences by numerous branches situated in the
occipital region, these branches anastomosing with the occipital, the
deep cervical, and the posterior spinal veins. It passes downward
along the vertebral artery through the foramina in the transverse pro-
cesses of the first six cervical vertel)r?e, passes over the subclavian
artery, and terminates by emptying into the innominate vein near its
origin : it sometimes terminates in the subclavian. This vein is sup-
plied near its termination by either a single or a double valve. Occa-
sionally, as it passes down the body of the vertebrae, it receives two
branches, one opening into the vessel as it enters the foramen in the
transverse process of the atlas, while the other is received oj^posite the
seventh or vertebral prominence.
The Venous Sinuses of the Cranium
are large canals (Fig. 113) analogous to veins, and into which the vari-
ous veins of the brain, the ophthalmic vein, and several emissary veins
Fig. 113.
Foramen CctcurA
Toreular
Vertical Section of the Skull, showing the sinuses of the duia mater.
empty. They are composed of two coats, internal and external. The
internal coat is a delicate serous membrane, being a continuation of the
lining membrane of the veins, while the outer coat is formed by the
dura mater. From this fact they are known as the sinuses of the dura
mater. They are fifteen in number, and are divided into two groups
the supero-posterior and the infero-anterior.
The Supero-posterior Group is composed of six sinuses
Superior longitudinal. Occipital,
Inferior longitudinal, Eight lateral,
Straight, Left lateral.
Vol. I.—17
BLOOD-VESSEL SYSTEM OF THE HEAD, ETC. : 257
artery, and terminates by emptying into the internal jugular vein
slightly above the level of the cricoid cartilage.
The Vertebral Vein commences by numerous branches situated in the
occipital region, these branches anastomosing with the occipital, the
deep cervical, and the posterior spinal veins. It passes downward
along the vertebral artery through the foramina in the transverse pro-
cesses of the first six cervical vertel)r?e, passes over the subclavian
artery, and terminates by emptying into the innominate vein near its
origin : it sometimes terminates in the subclavian. This vein is sup-
plied near its termination by either a single or a double valve. Occa-
sionally, as it passes down the body of the vertebrae, it receives two
branches, one opening into the vessel as it enters the foramen in the
transverse process of the atlas, while the other is received oj^posite the
seventh or vertebral prominence.
The Venous Sinuses of the Cranium
are large canals (Fig. 113) analogous to veins, and into which the vari-
ous veins of the brain, the ophthalmic vein, and several emissary veins
Fig. 113.
Foramen CctcurA
Toreular
Vertical Section of the Skull, showing the sinuses of the duia mater.
empty. They are composed of two coats, internal and external. The
internal coat is a delicate serous membrane, being a continuation of the
lining membrane of the veins, while the outer coat is formed by the
dura mater. From this fact they are known as the sinuses of the dura
mater. They are fifteen in number, and are divided into two groups
the supero-posterior and the infero-anterior.
The Supero-posterior Group is composed of six sinuses
Superior longitudinal. Occipital,
Inferior longitudinal, Eight lateral,
Straight, Left lateral.
Vol. I.—17
