Bridging Veins Of The Brain

Cerebral Veins

The superficial cerebral veins (cortical veins) carry blood from the outer 1-2 cm of the brain surface to large drainage channels such as the superior and inferior sagittal sinuses, the great cerebral vein of Galen, the straight sinus, and the tentorial veins. Thus, the cerebellar veins drain blood from the cerebellar surface into the superior vermian vein and thence into the great cerebral vein, straight sinus, and transverse sinuses. The deep cerebral veins (central veins) drain blood from the inner regions of the brain (hemispheric white matter, basal ganglia, corpus callosum, choroid plexus) and from a few cortical areas as well.

Superficial cerebral veins (cortical veins). The superficial cerebral veins are classified by their location as prefrontal, frontal, parietal, and occipital. Except for the occipital veins, which empty into the transverse sinus, these veins all travel over the cerebral convexity to join the superior sagittal sinus. They are termed bridging veins at their distal end, where they pierce the arachnoid membrane and bridge the sub-arachnoid space to join the sinus. The superficial middle cerebral vein (not shown) usually follows the posterior ramus of the Sylvian fissure and the fissure itself to the cavernous sinus. The inferior cerebral veins drain into the cavernous sinus, superior petrosal sinus, and transverse sinus. The superior cerebral veins drain into the superior sagittal sinus.

Deep cerebral veins (central veins). The internal cerebral vein arises bilaterally at the level of the interventricular foramen (of Monro). It traverses the transverse cerebral fissure to a point just inferior to the splenium of the corpus callosum. The venous angle at its junction with the superior thalamostriate vein can be seen in a laterally projected angiogram. The two internal cerebral veins join under the splenium to form the great cerebral vein (of Galen), which receives the basal vein (of Rosenthal) and then empties into the straight sinus at the anterior tentorial edge at the level of the quadrigeminal plate. The basal vein of Rosenthal is formed by the union of the anterior cerebral vein, the deep middle cerebral vein, and the striate veins. It passes posterome-dial to the optic tract, curves around the cerebral peduncle, and empties into the internal vein or the great cerebral vein posterior to the brain stem.

Posterior fossa. The anterior, middle, and posterior veins of the posterior fossa drain into the great cerebral vein, the petrosal vein, and the tentorial and straight sinuses, respectively.

Extracerebral Veins

The extracerebral veins—most prominently, the dural venous sinuses—drain venous blood from the brain into the sigmoid sinuses and jugular veins.

The diploic veins drain into the extracranial veins of the scalp and the intracranial veins (dural venous sinuses).

The emissary veins connect the sinuses, diploic veins, and superficial veins of the skull. Infections sometimes travel along the emissary veins from the extracranial to the intracranial compartment.

The veins of the brain empty into the superior and inferior groups of dural venous sinuses. The sinuses of the superior group (the superior and inferior sagittal, straight, and occipital sinuses) join at the confluence of the sinuses (torcular Herophili), which drains into both transverse sinuses and thence into the sigmoid sinuses and internal jugular veins. The sinuses of the inferior group (superior and inferior petrosal sinuses) join at the cavernous sinus, which drains into the sigmoid sinus and internal jugular vein via the inferior petrosal sinus, or into the internal vertebral plexus via the basilar plexus.

Superior cerebral veins, bridging veins

Cavernous sinus

Inferior petrosal -sinus

Internal jugular v. Cerebral veins

Superior cerebral veins, bridging veins

Cavernous sinus

Great Cerebral Vein Galen Tentorial

Emissary v.

Superior sagittal sinus

Cerebral vein

Superior sagittal sinus

-Venous angle

Internal cerebral v. Great cerebral v. (Galen) Basal v. (Rosenthal) Straight sinus Confluence of sinuses

Scalp vein Diploic veins

Scalp vein Diploic veins

Emissary v.

Superior sagittal sinus

Cerebral vein

Bridging Veins The Brain

Superior cerebral v., bridging vein

Extracerebral veins

Superior cerebral v., bridging vein

Extracerebral veins

Superior cerebral veins, bridging veins

Inferior sagittal sinus

Venous angle

Ophthalmic v. Sphenoparietal sinus Basilar plexus Middle meningeal v. Petrosal v.-

Superior cerebral veins, bridging veins

Inferior sagittal sinus

Venous angle

Cerebral Veins Straight Sinus

-Transverse sinus

Superior petrosal sinus

Cerebral veins and sinuses

Superior sagittal sinus

Basal v. (Rosenthal)

Great cerebral v.

Straight sinus

Confluence of sinuses

Sigmoid sinus

-Transverse sinus

Superior petrosal sinus

Cerebral veins and sinuses

Craniocervical Veins

Anastomotic channels connect the cutaneous veins of the two sides of the head. Venous blood from the facial, temporal, and frontal regions drains into the facial and retromandibular veins and thence into the internal jugular vein. Some blood from the forehead drains via the naso-frontal, angular, and superior ophthalmic veins into the cavernous sinus. The occipital vein carries blood from the posterior portion of the scalp into the deep cervical vein and thence into the externaljugularvein. Blood from the jugular veins continues to the brachiocephalic vein, su-.O perior vena cava, and right atrium. The venous O channels in the spinal canal and the transcranial 3 emissary veins play no more than a minor role .i; in venous drainage. The pterygoid plexus links ^ the cavernous sinus, the facial vein, and the in-2 ternal jugular vein.

The numerous anastomoses between the ex-(<u tracranial and intracranial venous systems provide a pathway for the spread of infection from the scalp or face to the intracranial compartment. For example, periorbital infection may extend inward and produce septic thrombosis of the cavernous sinus.

which anastomoses with the occipital venous plexus and finally drains into the external jugular vein.

The pterygoid plexus lies between the tem-poralis, medial pterygoid, and lateral pterygoid muscles and receives blood from deep portions of the face, the external ear, the parotid gland, and the cavernous sinus, which it carries by way of the maxillary and retromandibular veins to the internal jugular vein.

Cervical Veins

The deep cervical vein originates from the occipital vein and suboccipital plexus. It follows the course of the deep cervical artery and vertebral artery to arrive at the brachiocephalic vein, which it joins.

The vertebral vein, which also originates from the occipital vein and suboccipital plexus, envelops the vertebral artery like a net and accompanies it through the foramina transversaria of the cervical vertebrae, collecting blood along the way from the cervical spinal cord, meninges, and deep neck muscles through the vertebral venous plexus, and finally joining the brachio-cephalic vein.

Cranial Veins

The facial vein drains the venous blood from the face and anterior portion of the scalp. It begins at the inner canthus as the angular vein and communicates with the cavernous sinus via the superior ophthalmic vein. Below the angle of the mandible, it merges with the retromandibu-lar vein and branches of the superior thyroid and superior laryngeal veins. It then drains into the internal jugular vein in the carotid triangle. The veins of the temporal region, external ear, temporomandibular joint, and lateral aspect of the face join in front of the ear to form the retro-mandibular vein, which either joins the facial vein or drains directly into the internal jugular vein. Its upper portion gives off a prominent dorsocaudal branch that joins the posterior auricular vein over the sternocleidomastoid muscle to communicate with the external jugular vein. Venous blood from the posterior portion of the scalp and the mastoid and occipital emissary veins drains into the occipital vein,

Superficial — temporal veins

Supratrochlear v.

Nasofrontal v.

Angular v. — Infraorbital v.

Facial v

Submental v.

Anterior jugular v.

Left brachio-cephalic v.

Lymph vessels joining to form thoracic duct

Superficial — temporal veins

Supratrochlear v.

Nasofrontal v.

Angular v. — Infraorbital v.

Submental v.

Cranial Vein Pterygoid Plexus

Suboccipital venous plexus

- Pterygoid plexus Retromandibular v.

Subclavian v.

Suboccipital venous plexus

- Pterygoid plexus Retromandibular v.

External jugular v.

Internal jugular v.

Transverse cervical v.

Suprascapular v.

Subclavian v.

Extracranial veins c o o c

Arteries

Most of the blood supply of the spinal cord is supplied by the segmental spinal arteries, while relatively little comes from the vertebral arteries via the anterior and posterior spinal arteries. The segmental and spinal arteries are linked by numerous anastomoses. Segmental arteries. The vertebral, ascending cervical, and deep cervical arteries give off cervical segmental branches; the thoracic and abdominal aorta give off thoracolumbar segmental branches via the posterior intercostal and lumbar arteries.

The segmental arteries give off radicular branches that enter the intervertebral foramen and supply the anterior and posterior roots and spinal ganglion of the corresponding level. The spinal cord itself is supplied by unpaired medullary arteries that originate from segmental arteries. The anatomy of these medullary arteries is variable; they usually have 5 to 8 larger ventral and dorsal branches that join up with the anterior and posterior spinal arteries. Often there is a single large radicular branch on one side, the great radicular artery (of Adam-kiewicz), that supplies the entire lower two-thirds of the spinal cord. It usually enters the spinal canal in the lower thoracic region on the left side.

Spinal arteries. The spinal arteries run longitudinally down the spinal cord and arise from the vertebral artery (p. 14). The unpaired anterior spinal artery lies in the anterior median fissure of the spinal cord and supplies blood to the anterior two-thirds of the cord. The artery's diameter steadily increases below the T2 level. The two posterior spinal arteries supply the dorsal columns and all but the base of the dorsal horns bilaterally. Numerous anastomoses of the spinal arteries produce a vasocorona around the spinal cord. The depth of the spinal cord is supplied by these arteries penetrating it from its outer surface and by branches of the anterior spinal artery penetrating it from the anterior median fissure (sulcocommissural arteries).

omy is variable, to the anterior and posterior spinal veins, which form a reticulated network in the pia mater around the circumference of the cord and down its length. The anterior spinal vein drains the anterior two-thirds of the gray matter, while the posterior and lateral spinal veins drain the rest of the spinal cord. These vessels empty by way of the radicular veins into the external and internal vertebral venous plexuses, groups of valveless veins that extend from the coccyx to the base of the skull and communicate with the dural venous sinuses via the suboccipital veins. Venous blood from the cervical spine drains by way of the vertebral and deep cervical veins into the superior vena cava; from the thoracic and lumbar spine, by way of the posterior intercostal and lumbar veins into the azygos and hemiazygos veins; from the sacrum, by way of the median and lateral sacral veins into the common iliac vein.

Watershed Zones

Because blood can flow either upward or downward in the anterior and posterior spinal arteries, the tissue at greatest risk of hypoperfu-sion is that located at a border zone between the distributions of two adjacent supplying arteries ("watershed zone"). Such vulnerable zones are found in the cervical, upper thoracic, and lower thoracic regions (ca. C4, T3-T4, and T8-T9).

Spinal Veins

Blood from within the spinal cord travels through the intramedullary veins, whose anat-

- Posterior spinal a.

Anterior spinal a.

- Radicular a.

- Watershed Vertebral a. Ascending cervical a. Watershed

Aortic arch

Thoracic intercostal a.

Vertebral v.

Deep cervical v.

Spinal v. Radicular v. Inferior jugular v. Subclavian v. Right brachiocephalic v. Left brachiocephalic v.

Accessory hemiazygos v.

Azygos v.

Hemiazygos v.

Spinal arteries

Vasocorona Epidural space Ventral root Spinal branch

- Watershed

Great radicular a. (a. of Adamkiewicz)

Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Responses

  • uta
    What veins drain the brainstem?
    8 years ago
  • Malva
    What are bridging veins?
    7 years ago
  • matthias
    What is the difference between vertebral veins and jugular veins'?
    7 years ago
  • marina
    What vein drains the cervical spinal cord?
    7 years ago
  • filomena
    What is bridging sclerosis?
    6 years ago
  • olive findlay
    What is a bridging vein?
    5 years ago
  • Lewis Myers
    What is the connection between diploic veins and emissary veins?
    3 years ago
  • Joe
    How brindge vein is formed?
    2 years ago
  • bobbi
    Are bridging veins deep drainage or superficial brain?
    2 months ago

Post a comment