The cisterna magna (posterior cerebellomedullary cistern, or cerebellomedullary cistern) is the largest of the

subarachnoid cisterns The subarachnoid cisterns are spaces formed by openings in the subarachnoid space, an anatomic space in the meninges of the brain. The space is situated between the two meninges, the arachnoid mater and the pia mater. These cisterns are filled w ...

. It occupies the space created by the angle between the caudal/inferior surface of the cerebellum, and the dorsal/posterior surface of the

medulla oblongata The medulla oblongata or simply medulla is a long stem-like structure which makes up the lower part of the brainstem. It is anterior and partially inferior to the cerebellum. It is a cone-shaped neuronal mass responsible for autonomic (involun ...

(it is created by the arachnoidea that bridges this angle). The

fourth ventricle The fourth ventricle is one of the four connected fluid-filled cavities within the human brain. These cavities, known collectively as the ventricular system, consist of the left and right lateral ventricles, the third ventricle, and the fourth ...

communicates with the cistern via the unpaired midline

median aperture The median aperture (median aperture of fourth ventricle or foramen of Magendie) is an opening at the caudal portion of the roof of the fourth ventricle. It allows the flow of cerebrospinal fluid (CSF) from the fourth ventricle into the cisterna ...

. It is continuous inferiorly with the subarachnoid space of the

spinal canal In human anatomy, the spinal canal, vertebral canal or spinal cavity is an elongated body cavity enclosed within the dorsal bony arches of the vertebral column, which contains the spinal cord, spinal roots and dorsal root ganglia. It is a pro ...

. The cisterna magna contains the two

vertebral arteries The vertebral arteries are major arteries of the neck. Typically, the vertebral arteries originate from the subclavian arteries. Each vessel courses superiorly along each side of the neck, merging within the skull to form the single, midline ...

, the origins of the two

posterior inferior cerebellar arteries The posterior inferior cerebellar artery (PICA) is the largest branch of the vertebral artery. It is one of the three main arteries that supply blood to the cerebellum, a part of the brain. Blockage of the posterior inferior cerebellar artery can ...

, the glossopharyngeal nerve (CN IX), vagus nerve (CN X), accessory nerve (CN XI), hypoglossal nerve (XII), and

choroid plexus The choroid plexus, or plica choroidea, is a plexus of cells that arises from the tela choroidea in each of the ventricles of the brain. Regions of the choroid plexus produce and secrete most of the cerebrospinal fluid (CSF) of the central ...

. The vertebral artery and posterior inferior cerebellar artery of either side pass traverse either lateral portion of the cistern.

Etymology

The ''

Terminologia Anatomica ''Terminologia Anatomica'' (commonly abbreviated TA) is the international standard for human anatomy, human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology (FIPAT) a program of the Inter ...

'' classifies the terms ''cisterna magna'' and ''posterior cerebellomedullary cistern'' as synonyms. It does not recognise the term "''cerebellomedullary cistern"'' (neither as a synonym or distinct structure) but acknowledges the ''lateral cerebellomedullary cistern'' as a distinct structure. The 42nd edition of ''

Gray's Anatomy ''Gray's Anatomy'' is a reference book of human anatomy written by Henry Gray, illustrated by Henry Vandyke Carter and first published in London in 1858. It has had multiple revised editions, and the current edition, the 42nd (October 2020 ...

'' (2020) and 12th edition of ''Last's Anatomy'' (2011) recognise the ''cisterna magna'' and ''cerebellomedullary cistern'' as synonyms, and do not describe a separate ''lateral cerebellomedullary cistern''. According to the 8th edition of the ''Clinical Oriented Anatomy'' (2018), the cerebellomedullary cistern is subdivided into the ''posterior cerebellomedullary cistern'' (''cisterna magna''), and the ''lateral cerebellomedullary cistern''.

Clinical significance

The cisterna magna may be tapped with a needle inserted superior to the

posterior arch In anatomy, the atlas (C1) is the most superior (first) cervical vertebra of the spine and is located in the neck. The bone is named for Atlas of Greek mythology, just as Atlas bore the weight of the heavens, the first cervical vertebra suppor ...

atlas An atlas is a collection of maps; it is typically a bundle of world map, maps of Earth or of a continent or region of Earth. Advances in astronomy have also resulted in atlases of the celestial sphere or of other planets. Atlases have traditio ...

References

{{DEFAULTSORT:Cisterna Magna Meninges