Topics

Topic

design image
Lamina terminalis

The lamina terminalis is a thin, vertical membrane in the anterior wall of the third ventricle of the brain. It forms the anterior boundary of the third ventricle, stretching from the optic chiasm below to the anterior commissure above. Embryologically, it represents the rostral end of the neural tube and plays a crucial role in the development and separation of the telencephalon. In clinical and imaging practice, the lamina terminalis is an important anatomical landmark, especially in neuroendoscopic and vascular neurosurgery.

Synonyms

  • Anterior wall of the third ventricle

  • Rostral wall of the third ventricle

  • Terminal lamina

Function

  • Forms the anterior boundary of the third ventricle

  • Acts as a conduit for neuroendocrine signaling between the brain and the cerebrospinal fluid (CSF)

  • Serves as a barrier between the third ventricle and subarachnoid space

  • Important in neuroendoscopic procedures, such as third ventriculostomy

  • Contains part of the circumventricular organ, the organum vasculosum of the lamina terminalis (OVLT), which is involved in osmoregulation and thirst control

MRI Appearance

  • T1-Weighted Images:

    • Appears as a thin, hypointense (dark) linear structure

    • Seen as a low signal membrane forming the anterior border of the third ventricle, best appreciated on mid-sagittal images

  • T2-Weighted Images:

    • Also visualized as a thin, hypointense line

    • Surrounded by the hyperintense CSF of the third ventricle and the prechiasmatic cistern

  • FLAIR Sequence:

    • Remains a thin, hypointense line

    • The adjacent CSF signal is partially suppressed, making the lamina terminalis slightly more conspicuous but still subtle

CT Appearance

  • Not typically visualized as a distinct structure due to its thin, non-calcified membranous nature

  • Occasionally, the location can be inferred as the anterior wall of the third ventricle, bordered by CSF attenuation

  • Used as a landmark rather than a directly seen structure on CT

MRI images

Lamina terminalis mri 3t axial image

MRI images

Lamina terminalis mri 3t coronal image