The parietal bones are two bones in the skull which, when joined at a fibrous joint, form the sides and roof of the neurocranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin paries (-ietis), wall.
The great cerebral vein is one of the large blood vessels in the skull draining the cerebrum of the brain. It is also known as the vein of Galen, named for its discoverer, the Greek physician Galen.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain. Veins carry "used or spent" blood back to the heart, to remove carbon dioxide, lactic acid, and other metabolic products. The neurovascular unit regulates cerebral blood flow so that activated neurons can be supplied with energy in the right amount and at the right time. Because the brain would quickly suffer damage from any stoppage in blood supply, the cerebral circulatory system has safeguards including autoregulation of the blood vessels. The failure of these safeguards may result in a stroke. The volume of blood in circulation is called the cerebral blood flow. Sudden intense accelerations change the gravitational forces perceived by bodies and can severely impair cerebral circulation and normal functions to the point of becoming serious life-threatening conditions.
The diploic veins are large, thin-walled valveless veins that channel in the diploë between the inner and outer layers of the cortical bone in the skull, first identified in dogs by the anatomist Guillaume Dupuytren. A single layer of endothelium lines these veins supported by elastic tissue. They develop fully by the age of two years. The diploic veins drain this area into the dural venous sinuses. The four major trunks of the diploic veins found on each side of the head are frontal, anterior temporal, posterior temporal, and occipital diploic veins. They tend to be symmetrical, with the same pattern of large veins on each side of the skull. It has been suggested that the venous patterns they form resemble fingerprints in their individuality.
The falx cerebri is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure between the cerebral hemispheres of the human brain, separating the two hemispheres and supporting dural sinuses that provide venous and CSF drainage to the brain. It is attached to the crista galli anteriorly, and blends with the tentorium cerebelli posteriorly.
The cerebellar tentorium or tentorium cerebelli is an extension of the dura mater between the inferior aspect of the occipital lobes and the superior aspect of the cerebellum. The free border of the tentorium gives passage to the midbrain.
The coronary sinus is the largest vein of the heart. It drains over half of the deoxygenated blood from the heart muscle into the right atrium. It begins on the backside of the heart, in between the left atrium, and left ventricle; it begins at the junction of the great cardiac vein, and oblique vein of the left atrium. It receives multiple tributaries. It passes across the backside of the heart along a groove between left atrium and left ventricle, then drains into the right atrium at the orifice of the coronary sinus.
The dural venous sinuses are venous sinuses (channels) found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, and cerebrospinal fluid (CSF) from the subarachnoid space via arachnoid granulations. They mainly empty into the internal jugular vein. Cranial venous sinuses communicate with veins outside the skull through emissary veins. These communications help to keep the pressure of blood in the sinuses constant. The major dural venous sinuses included the superior sagittal sinus, inferior sagittal sinus, transverse sinus, straight sinus, sigmoid sinus and cavernous sinus. These sinuses play a crucial role in cerebral venous drainage. A dural venous sinus, in human anatomy, is any of the channels of a branching complex sinus network that lies between layers of the dura mater, the outermost covering of the brain, and functions to collect oxygen-depleted blood. Unlike veins, these sinuses possess no muscular coat.
The confluence of sinuses, torcular Herophili, or torcula is the connecting point of the superior sagittal sinus, straight sinus, and occipital sinus. It is below the internal occipital protuberance of the skull. It drains venous blood from the brain into the transverse sinuses. It may be affected by arteriovenous fistulas, a thrombus, major trauma, or surgical damage, and may be imaged with many radiology techniques.
The straight sinus, also known as tentorial sinus or the sinus rectus, is an area within the skull beneath the brain. It receives blood from the inferior sagittal sinus and the great cerebral vein, and drains into the confluence of sinuses.
The superior sagittal sinus, within the human head, is an unpaired area along the attached margin of the falx cerebri. It allows blood to drain from the lateral aspects of anterior cerebral hemispheres to the confluence of sinuses. Cerebrospinal fluid drains through arachnoid granulations into the superior sagittal sinus and is returned to venous circulation.
The inferior sagittal sinus, within the human head, is an area beneath the brain which allows blood to drain outwards posteriorly from the center of the head. It drains to the straight sinus, which connects to the transverse sinuses. See diagram : labeled in the brain as "SIN. SAGITTALIS INF.".
The transverse sinuses, within the human head, are two areas beneath the brain which allow blood to drain from the back of the head. They run laterally in a groove along the interior surface of the occipital bone. They drain from the confluence of sinuses to the sigmoid sinuses, which ultimately connect to the internal jugular vein. See diagram : labeled under the brain as "SIN. TRANS.".
The occipital vein is a vein of the scalp. It originates from a plexus around the external occipital protuberance and superior nuchal line to the back part of the vertex of the skull. It usually drains into the internal jugular vein, but may also drain into the posterior auricular vein. It drains part of the scalp.
The anterior cranial fossa is a depression in the floor of the cranial base which houses the projecting frontal lobes of the brain. It is formed by the orbital plates of the frontal, the cribriform plate of the ethmoid, and the small wings and front part of the body of the sphenoid; it is limited behind by the posterior borders of the small wings of the sphenoid and by the anterior margin of the chiasmatic groove. The lesser wings of the sphenoid separate the anterior and middle fossae.
The cerebellar veins are veins which drain the cerebellum. They consist of the superior cerebellar veins and the inferior cerebellar veins. The superior cerebellar veins drain to the straight sinus and the internal cerebral veins. The inferior cerebellar veins drain to the transverse sinus, the superior petrosal sinus, and the occipital sinus.
The sphenoparietal sinus is a paired dural venous sinus situated along the posterior edge of the lesser wing of either sphenoid bone. It drains into the cavernous sinus.
The following outline is provided as an overview of and topical guide to human anatomy:
The middle cerebral veins - the superficial middle cerebral vein and the deep middle cerebral vein - are two veins running along the lateral sulcus. The superficial middle cerebral vein is also known as the superficial Sylvian vein, and the deep middle cerebral vein is also known as the deep Sylvian vein. The lateral sulcus is also known as the Sylvian fissure.
