The cave of septum pellucidum (CSP), cavum septi pellucidi, or cavity of septum pellucidum is a slit-like space in the

septum pellucidum The septum pellucidum (Latin for "translucent wall") is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the corpus callosum down to the fo ...

that is present in fetuses but usually fuses during infancy. The septum pellucidum is a thin, laminated translucent vertical membrane in the midline of the brain separating the anterior horns of the right and left ventricles. It lies posterior to the

corpus callosum The corpus callosum (Latin for "tough body"), also callosal commissure, is a wide, thick nerve tract, consisting of a flat bundle of commissural fibers, beneath the cerebral cortex in the brain. The corpus callosum is only found in placental mam ...

. Persistence of the cave of septum pellucidum after infancy has been loosely associated with neural maldevelopment and several mental disorders that correlate with decreased brain tissue. The cave of septum pellucidum is bounded anteriorly by the genu of the

, superiorly by the body of the corpus callosum, posteriorly by the anterior limb and pillars of the fornix, inferiorly by the

anterior commissure The anterior commissure (also known as the precommissure) is a white matter tract (a bundle of axons) connecting the two temporal lobes of the cerebral hemispheres across the midline, and placed in front of the columns of the fornix. In most exist ...

and the rostrum of the corpus callosum, and laterally by the leaflets of the septum pellucidum. In

prenatal development Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

of the

fetus A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal deve ...

, the laminae of the septum pellucidum separate to form a small cavity – the cave of septum pellucidum. This is an important normal structure to identify in the sonographic assessment of the fetal brain. In post-natal life, the laminae of the septum pellucidum usually fuse, which obliterates the cavum. The cavity contains

cerebrospinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...

(CSF) that filters from the ventricles through the septal laminae. There are individual differences in the degree of CSP; whereas some have complete closure of the cavum, others present with a small degree (4–6 mm wide, in the

coronal plane The coronal plane (also known as the frontal plane) is an anatomical plane that divides the body into dorsal and ventral sections. It is perpendicular to the sagittal and transverse planes. Details The coronal plane is an example of a longitud ...

) of incomplete closure. The most common type of CSP is noncommunicating; that is, it does not connect to the brain's ventricular system. Because of this lack of communication, the previous use of the term "fifth ventricle" is no longer used, and the fifth ventricle is the name often used for the

terminal ventricle The central canal (also known as spinal foramen or ependymal canal) is the cerebrospinal fluid-filled space that runs through the spinal cord. The central canal lies below and is connected to the ventricular system of the brain, from which it r ...

. CSP is present in 100% of fetuses, but over 85% of them fuse by 3–6 months after birth.

Cause

The cause of CSP is basically unknown, although it is thought that prenatal alcohol exposure plays a significant role.

Marker for fetal neural maldevelopment

CSP is a marker for fetal neural maldevelopment. The septum pellucidum is a thin, triangular, vertical membrane separating the anterior horns of the left and right lateral ventricles of the brain. It runs as a sheet from the

down to the fornix. During fetal development at approximately the twelfth week of

gestation Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...

, a space forms between two laminae, which is the CSP. At approximately the twentieth week of gestation, the laminae start to close. This closure ends shortly after birth (3–6 months postnatally). Fusion of the CSP is attributed to rapid development of the alvei of the

hippocampus The hippocampus (via Latin from Greek , 'seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, a ...

amygdala The amygdala (; plural: amygdalae or amygdalas; also '; Latin from Greek, , ', 'almond', 'tonsil') is one of two almond-shaped clusters of nuclei located deep and medially within the temporal lobes of the brain's cerebrum in complex verteb ...

septal nuclei The septal area (medial olfactory area), consisting of the lateral septum and medial septum, is an area in the lower, posterior part of the medial surface of the frontal lobe, and refers to the nearby septum pellucidum. The septal nuclei are loca ...

, fornix,

and other midline structures. Lack of such limbic development interrupts this posterior-to-anterior fusion, resulting in preservation of the CSP into adulthood.

Association with mental disorders

CSP has been loosely associated with

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social withdra ...

post-traumatic stress disorder Post-traumatic stress disorder (PTSD) is a mental and behavioral disorder that can develop because of exposure to a traumatic event, such as sexual assault, warfare, traffic collisions, child abuse, domestic violence, or other threats on ...

traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic b ...

, as well as with

antisocial personality disorder Antisocial personality disorder (ASPD or infrequently APD) is a personality disorder characterized by a long-term pattern of disregard of, or violation of, the rights of others as well as a difficulty sustaining long-term relationships. Lack ...

. CSP is one of the distinguishing features of individuals displaying symptoms of

dementia pugilistica Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease linked to repeated trauma to the head. The encephalopathy symptoms can include behavioral problems, mood problems, and problems with thinking. The disease often gets worse o ...

(chronic traumatic encephalopathy).Neuropathol Exp Neurol. 2009 Jul;68(7):709-35. doi: 10.1097/NEN.0b013e3181a9d503. Chronic traumatic encephalopathy in athletes: progressive tauopathy after repetitive head injury. McKee AC, Cantu RC, Nowinski CJ, Hedley-Whyte ET, Gavett BE, Budson AE, Santini VE, Lee HS, Kubilus CA, Stern RA.

References in film

*In the 1990 film, ''

Rocky V ''Rocky V'' is a 1990 American sports drama film directed by John G. Avildsen (the first time since the first film of the franchise), written by and starring Sylvester Stallone. It is the sequel to ''Rocky IV'' (1985) and is the fifth install ...

'', a destitute

Rocky Balboa Robert "Rocky" Balboa (also known by his ring name The Italian Stallion), is a fictional title character and the protagonist of the ''Rocky'' film series. The character was created by Sylvester Stallone, who has also portrayed him in all eigh ...

visits a doctor before competing in any further boxing matches. A brain scan reveals that he has cavum septi pellucidi brought on by head trauma, especially after his last fight with

Ivan Drago Ivan Vasilyevich Drago (russian: Иван Васильевич Драго, ) is a Soviet-Russian fictional character from the ''Rocky'' film series. He first appears in the 1985 film ''Rocky IV'', in which he is the central antagonist and riv ...

. His wife

Adrian Adrian is a form of the Latin language, Latin given name Adrianus (given name), Adrianus or Hadrianus (disambiguation), Hadrianus. Its ultimate origin is most likely via the former river Adria (river), Adria from the Venetic language, Venetic and ...

urges him to retire, and he reluctantly does so.

References

External links