Skip to main content
Advertisement

Main menu

  • Home
  • Content
    • Current Issue
    • Publication Preview--Ahead of Print
    • Past Issue Archive
    • Case of the Week Archive
    • Classic Case Archive
    • Case of the Month Archive
    • COVID-19 Content and Resources
  • For Authors
  • About Us
    • About AJNR
    • Editors
    • American Society of Neuroradiology
  • Submit a Manuscript
  • Podcasts
    • Subscribe on iTunes
    • Subscribe on Stitcher
  • More
    • Subscribers
    • Permissions
    • Advertisers
    • Alerts
    • Feedback
  • Other Publications
    • ajnr

User menu

  • Subscribe
  • Alerts
  • Log in

Search

  • Advanced search
American Journal of Neuroradiology
American Journal of Neuroradiology

American Journal of Neuroradiology

  • Subscribe
  • Alerts
  • Log in

Advanced Search

  • Home
  • Content
    • Current Issue
    • Publication Preview--Ahead of Print
    • Past Issue Archive
    • Case of the Week Archive
    • Classic Case Archive
    • Case of the Month Archive
    • COVID-19 Content and Resources
  • For Authors
  • About Us
    • About AJNR
    • Editors
    • American Society of Neuroradiology
  • Submit a Manuscript
  • Podcasts
    • Subscribe on iTunes
    • Subscribe on Stitcher
  • More
    • Subscribers
    • Permissions
    • Advertisers
    • Alerts
    • Feedback
  • Follow AJNR on Twitter
  • Visit AJNR on Facebook
  • Follow AJNR on Instagram
  • Join AJNR on LinkedIn
  • RSS Feeds
LetterLETTER

The Evolutionary and Embryologic Basis for the Development and Anatomy of the Cavum Veli Interpositi

American Journal of Neuroradiology July 1999, 20 (7) 1383-1684;
  • Article
  • Figures & Data
  • Info & Metrics
  • References
  • PDF
Loading

I read with interest the recent article by Chen et al entitled, “Sonographic Characteristic of the Cavum Velum Interpositum” (1). The regional anatomy of the cavum veli interpositi is complex and difficult to understand. I would like to point out the following anatomic information that is in variance with some of the statements made in the above-mentioned publication.

The ependymal roof of the third ventricle is covered by a double layer of pia mater, the tela choroidea (2). The embryologic basis for this double-layered tela choroidea was outlined diagrammatically in 1932 By Frazer (3), modified by Brash (4), and reproduced in the neuroradiologic literature (5). It results from the overlapping of the third ventricle by the enlarging forebrain (Fig). During an early fetal stage, the prosencephalon and diencephalon are covered by a continuous layer of pia mater. With further brain development, the expanding cerebral vesicles of the forebrain, covered by its own pia mater, overlaps the pia mater of the third ventricle, resulting in the double-layered tela choroidea (velum interpositum) of the roof of the third ventricle. The anterior aspect of the tela choiroidea, which is closed, is at the interventricular foramen where the pia mater folds on itself. When the posterior end remains open, the potential space between the double layers of the tela choroidea forms the cavum veli interpositi that communicates with the quadrigeminal cistern. The internal cerebral veins are located between the two layers of the cavum veli interpositi (2).

Figure
  • Download figure
  • Open in new tab
  • Download powerpoint

FIG. Diagram demonstrating the formation of the double-layered tela choroidea (velum interpositum) of the third ventricle in the human.

1) The developing neural tube includes the forebrain (FB) which is surrounded by the pia mater (broken line).

2) and 3) The expanding vesicle of the cerebral hemisphere (HV) carries its own pia mater (b) which overlaps the pia mater (a) of the third ventricle. IF signifies intraventricular foramen.

4) A double layer of pia mater (b, a) is interposed between the two cerebral vesicles and the third ventricle (3V). E signifies ependyma.

5) The two layers of pia mater (b, a) over the third ventricle persist after connection of the hemispheres by the commissures.

Certain human embryologic changes are a “recapitulation” of evolutionary modifications. Therefore, examining the changing anatomy of various adult vertebrate brains facilitates understanding the overlapping of the third ventricle by the expanding human fetal cerebrum (5). In the shark's linear brain, the cerebrum is anterior to the diencephalon. The entire roof of the diencephalon (third ventricle) is visible, and consists of a single layer of pia mater covered by a prominent venous plexus. In reptiles and primates, the expanding cerebrum overlaps the diencephalon, resulting in the double-layered tela choroidea of the third ventricle.

In summary:

  • The velum interpositum is the double-layered tela choroidea of the third ventricle.

  • The cavum veli interpositi is within the double-layered tela choroidea of the third ventricle, not superior to it.

  • The internal cerebral veins are within the cavum veli interpositi, not inferior to it.

  • The correct nomenclature is velum interpositum and cavum veli interpositi.

  • Finally, a discussion of fluid-filled structures in the pineal region should include an enlarged suprapineal recess of the third ventricle. This recess may be quite large, and may extend posteriorly below the splenium (5, 6).

References

  1. ↵
    Chen CY, Chen FH, Lee CC, Lee KW, Hsiao HS, Sonographic characteristic of the Cavum Velum Interpositum.. AJNR Am J Neuroradiol 1998;19:1631-1635
    Abstract
  2. ↵
    Williams PL, Warwick R, Dyson M, Bannister LH, ed. Gray's Anatomy. 37th ed. London: Churchill Livingstone; 1989;1019-1081
  3. ↵
    Frazer JE, A Manual of Embryology. New York: William Wood; 1932;
  4. ↵
    Brash JC, Cunningham's Textbook of Anatomy. 9th ed. New York: Oxford University Press; 1951;
  5. ↵
    Kier EL, The cerebral ventricles: a phylogentic and ontogentic study.. In: Newton TH, Potts DG, eds. Radiology of the Skull and Brain. St. Louis: C V Mosby; 1977;2787-2914
  6. Rosenbaum AE, Hawkins RL, Newton TH, The third ventricle.. In: Newton TH, Potts DG, eds. Radiology of the Skull and Brain. St. Louis: C V Mosby; 1978;3398-3440
  • Copyright © American Society of Neuroradiology
PreviousNext
Back to top

In this issue

American Journal of Neuroradiology
Vol. 20, Issue 7
1 Jul 1999
  • Table of Contents
  • Index by author
Advertisement
Print
Download PDF
Email Article

Thank you for your interest in spreading the word on American Journal of Neuroradiology.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
The Evolutionary and Embryologic Basis for the Development and Anatomy of the Cavum Veli Interpositi
(Your Name) has sent you a message from American Journal of Neuroradiology
(Your Name) thought you would like to see the American Journal of Neuroradiology web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
The Evolutionary and Embryologic Basis for the Development and Anatomy of the Cavum Veli Interpositi
American Journal of Neuroradiology Jul 1999, 20 (7) 1383-1684;

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Share
The Evolutionary and Embryologic Basis for the Development and Anatomy of the Cavum Veli Interpositi
American Journal of Neuroradiology Jul 1999, 20 (7) 1383-1684;
Reddit logo Twitter logo Facebook logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • References
  • Figures & Data
  • Info & Metrics
  • References
  • PDF

Related Articles

  • No related articles found.
  • PubMed
  • Google Scholar

Cited By...

  • No citing articles found.
  • Crossref
  • Google Scholar

This article has not yet been cited by articles in journals that are participating in Crossref Cited-by Linking.

More in this TOC Section

  • Fair Performance of CT in Diagnosing Unilateral Vocal Fold Paralysis
  • Reply:
  • Regarding “Altered Blood Flow in the Ophthalmic and Internal Carotid Arteries in Patients with Age-Related Macular Degeneration Measured Using Noncontrast MR Angiography at 7T”
Show more Letter

Similar Articles

Advertisement

News and Updates

  • Lucien Levy Best Research Article Award
  • Thanks to our 2022 Distinguished Reviewers
  • Press Releases

Resources

  • Evidence-Based Medicine Level Guide
  • How to Participate in a Tweet Chat
  • AJNR Podcast Archive
  • Ideas for Publicizing Your Research
  • Librarian Resources
  • Terms and Conditions

Opportunities

  • Share Your Art in Perspectives
  • Get Peer Review Credit from Publons
  • Moderate a Tweet Chat

American Society of Neuroradiology

  • Neurographics
  • ASNR Annual Meeting
  • Fellowship Portal
  • Position Statements

© 2023 by the American Society of Neuroradiology | Print ISSN: 0195-6108 Online ISSN: 1936-959X

Powered by HighWire