2003-01-16-12 Cavum Vergae © Mansour www.thefetus.net/
Ghada M. Mansour
Maternity Hospital, Fetal Care unit, Ain Shams University, Cairo, Egypt
Synonyms: Verga's ventricle, the sixth ventricle, the ventricle of Strambio, ventriculus fornicis, ventriculus triangularis, and the canal aqueduct.
Definition: The cavum vergae is the posterior extension of the cavum septi pellucidi. It is also called the sixth ventricle, which is a misnomer because the cavum does not contain cerebrospinal fluid nor is it lined by ependyma.(1)
History: The cavity was first described by the Italian anatomist, Andrea Verga, in 1851.(2) It may exist as a separate cavity rather than communicating with the cavum septi pellucidi.
Incidence: The incidence of the cavum vergae was 2.3% in 1032 brains.(5)
Verga's ventricle is present in 1-9% of human brains and was described by Verga in 1851 according to Lang (1983).(3)
In most adult brains both cavum septi pellucidi and cavum vergae are absent or are at most potential, but in every 100 necropsies actual cavities of varying size will be seen. Neither cavity can be regarded as part of the great ventricular system in which cerebrospinal fluid forms and through which it circulates.
Anatomy and Embryology: In many older textbooks of anatomy there was a brief but accurate description of two cavities ,Cavum septi pellucidi, and cavum vergae, Dandy described these as follows:
"The nomenclature, however, is not uniform. For example, the cavum septi pellucidi is perhaps better known as the fifth ventricle, and the cavum vergae is called Verga's ventricle, the sixth ventricle, the ventricle of Strambio, ventriculus fornicis, ventriculus triangularis, and the canal aqueduct All these cysts are normal structures in the fetus and tend to regress with development.(Fig 1)
Fig 1, Appearance of cavum verga by ultrasound.
Position and Boundaries of the Cavities: The corpus callosum defines the anterior, superior and posterior limits of the two cavities which, when not continuous, are separated from each other by the anterior limit of the fornix as it courses obliquely backward and upward from the anterior comissure to the body of the corpus callosum. Being of congenital origin, the two cavities are doubtless dependent on the development of the corpus callosum and the fornix. They may coexist and be isolated from each other when the fornix is intact; they may coexist and be in communication through a defect
in the fornix, or they may form a single large cavity when the fornix is not attached to the corpus callosum.(8).
The cavum septi pellucidi is frequently present when the cavum vergae is absent, and Verga"s cavity may be present when the cavum septi pellucidi is absent. Kauffmann stated that the cavum vergae may exist on one side of the midline and be absent on the other.
The cavum vergae has the following boundaries anteriorly, the anterior limb of the fornix, superiorly, the body of the corpus callosum, posteriorly, the splenium of the corpus callosum, inferiorly, the psalterium (lyra davidis) and hyppocampal commissure, the fibers of which bridge the space between the diverging posterior pillars of the fornix. This cavity is also triangular when viewed from the side. The cavum vergae flares out laterally on both sides with the curve of the fornix and pushes under the lateral ventricles at its extreme lateral extensions.
In most adult brains both spaces are absent or are at most potential, but in every 100 necropsies actual cavities of varying size will be seen. Neither cavity can be regarded as part of the great ventricular system in which cerebrospinal fluid forms and through which it circulates.(8)
Cavum Septum Pellucidi: Demarcated anteriorly by the genu of the corpus callosum, posteriorly by the colums and body of the fornix, superiorly by the body of the corpus collusum, and inferiorly by the rostrum of the corpus callosum.(2,6) posteriorly, the anterior limb and pillars of the fornix, inferiorly, the rostrum of the corpus callosum and the anterior commissure, laterally, the layers of the septum pellucidum. Viewed laterally, the cavum septi pellucidi is roughly triangular with the base at the corpus callosum. Viewed in cross-section the cavity is also triangular with the base at thecorpus callosum.(Fig2).
Fig 2 Anatomy of Cavum septum pellucidum and cavum vergae
Cavum Vergae : Lies directly behind the CSP. the boundaries are the corpus callosum superiorly, the hippocampal commisure inferiorly, the crus of the fornix laterally, and the splenium of the corpus callosum posteriorly. (2,6). (Fig2,3)
1) Cyst of the cavum septi pellucidi and cavum Vergae with posterior cranial fossa extension: case report: (5)
The cavum septi pellucidi (CSP) and cavum Vergae (CV) are frequently seen in premature and term infants. These cavities rarely enlarge and become symptomatic , a giant CSP and CV cyst was cdescribed in an 18-month-old boy, extending to the posterior cranial fossa and causing hydrocephalus.
2) Cavum septum pellucidum-Cavum vergae-macrocephaly-seizures-mental retardation syndrome:
Cavity of septum pellucidum, Verga"s ventricle, macrocephaly, seizures, and mental retardation was reported in two brothers.
Major Features (7)
Head and neck: Macrobrachycephaly, craniofacial abnormalities,
Nervous system, cavitas septi pellucidi, cavum vergae, and epilepsy.
Growth and development: Mental, speech, and motor retardation.
Heredity: The syndrome is familial.
1- Backman, E. (1924) Septum pellucidum and Verga"s ventrikel. Upsala Läkarefören. Forhandl. N. F., 29:215.
2- Dandy, W.E. (1931) Congenital cerebral cysts of the cavum septi pellucidi (fifth ventricle) and cavum vergae (sixth ventricle). Arch. Neurol. Psychiatry 25:44-66.
3- Lang, J. (1983) Clinical Anatomy of the Head. Neurocranium, Orbit, Craniocervical Regions. Springer Verlag, Berlin Heidelberg, New York.
4-- Mori, K. (1985) Anomalies of the central nervous system. Neuroradiology and Neurosurgery. Thieme-Stratton, Inc., New york.
5- Schwidde, J.T. (1952) Incidence of cavum septi pellucidi and cavum vergae in 1032 human brains. Arch. Neurol. Psychiatry 67:625-632.
6- Zellweger, H. and E.F. Van Epps. (1959) The cavum veli interpositi and its differentiation from cavum vergae. Am. J. Roentgenology 87:793-805.
7-National library of medicineFrom Dandy, W.E. Congenital cerebral cysts of the cavum septi pellucidi (fifth ventricle) and cavum vergae (sixth ventricle). Diagnosis and treatment. Arch. Neurol Psychiatry 25:44-66,
8- Illustrated Encyclopedia of Human Anatomic Variation: Opus III: Nervous System