The straight sinus, also known as tentorial sinus or the , is an area within the

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

beneath the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...

. It receives blood from the

inferior sagittal sinus The inferior sagittal sinus (also known as inferior longitudinal 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 (from the center of the brain) to ...

and the

great cerebral vein 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. However, it is not the only vein with this epon ...

, and drains into the

confluence of sinuses The confluence of sinuses (Latin: confluens sinuum), 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 dr ...

Structure

The straight sinus is situated within the

dura mater In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...

, where the

falx cerebri The falx cerebri (also known as the cerebral falx) is a large, crescent-shaped fold of dura mater that descends vertically into the longitudinal fissure between the cerebral hemispheres of the human brain,Saladin K. "Anatomy & Physiology: The Uni ...

meets the midline of

tentorium cerebelli The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes. Structure The cerebellar tentorium is an arch ...

. It forms from the confluence of the

and the

. It may also drain blood from the

superior cerebellar veins The cerebellar veins are veins which drain the cerebellum. They consist of the superior cerebellar veins and the inferior cerebellar veins (dorsal cerebellar veins). The superior cerebellar veins drain to the straight sinus and the internal cer ...

and veins from the falx cerebri. In cross-section, it is triangular, contains a few transverse bands across its interior, and increases in size as it proceeds backward. It is usually around 5 cm long.

Variation

The straight sinus is usually an unpaired structure. However, there may be two straight sinuses, which may be one on top of the other or parallel.

Function

The straight sinus allows blood to drain from the inferior center of the head outwards posteriorly. It receives blood from the

, posterior cerebral veins,

and veins from the falx cerebri.

Additional images

File:Gray569.png, Tentorium cerebelli from above. File:Straight sinus.jpg, Straight sinus

References

External links