The basal cistern, better known as the interpeduncular cistern, is one of the three major openings of the brain's subarachnoid space. This is the cavity between the arachnoid and pia mater that accounts for two of the three membranes covering the central nervous system. The other two cisterns in this region of the brain are the cistern magna and the pontificate cistern.
The basal or interpeduncular cistern is located where the arachnoid mater crosses between the two parts of the brain's lower region. The arachnoid mater is one of the membranes that covers the components of the central nervous system, or the brain and spinal cord. This is known as the temporal lobe. It is a region of the brain that plays an essential part in processing sound information.
The term "basal cistern" refers to the opening's location at the base of a pair of stem-like fibrous bundles called cerebral peduncles. These structures are part of a larger network of cells that connect the brain's different sections. The "interpeduncular cistern" term is more popular, since the cistern can be better described as forming an enclosure for the peduncles.
At the middle of the peduncles is the interpeduncular fossa. This is a trench at the base of the brain with the shape of a diamond. The basal cistern also envelops the Circle of Willis. Named after the 17th-century English physician who discovered it, it is a circular network of arteries responsible for transporting blood to the brain. The Circle of Willis is made up of the anterior cerebral and anterior communicating arteries located at the front, the internal carotid artery located in the middle, and the posterior cerebral and posterior communicating arteries at the back.
At the front of the basal cistern is the second opening of the subarachnoid space called the pontine cistern. It contains the Basilar artery, which is actually located at the rear of the Circle of Willis. The biggest of the three cisterns, however, is the cisterna magna. Located at the opposite end of the basal cistern and pontine cistern, it is also called the cerebellomedullary cistern because it lines the brain's cerebellum.
Openings of the brain such as the basal cistern are often mentioned at the omission of others. The superior cistern, for instance, can also be found alongside the cerebellum. In fact, it contains a large vein that drains that particular region of the brain. In some cases, this opening is called the cistern of the great cerebral vein, which consists of the superior and ambient cisterns.