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.