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, t ...

beneath the

brain The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special ...

. 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, and drains into the confluence of sinuses.

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 syste ...

, where the falx cerebri 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 arche ...

. It forms from the confluence of the

and the great cerebral vein. 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 cere ...

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

, great cerebral vein, 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