Topics

Topic

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Pineal recess

The pineal recess is a small, narrow cavity in the brain, forming a posterior extension of the third ventricle toward the pineal gland. This anatomic feature lies between the posterior commissure and the pineal gland, and is part of the ventricular system that contains cerebrospinal fluid (CSF). It plays a role in the interface between the third ventricle and the pineal gland, and is sometimes relevant in neuroimaging and neurosurgical approaches to the pineal region.

Synonyms

  • Recessus pinealis (Latin)

  • Pineal ventricular recess

  • Posterior recess of the third ventricle

Function

  • Serves as the posterior outpouching of the third ventricle toward the pineal gland

  • Contains cerebrospinal fluid (CSF)

  • Acts as an anatomic landmark in imaging and surgery

  • May be involved in the pathway for spread of lesions or cysts from the third ventricle to the pineal region

MRI Appearance

T2-Weighted Images

  • Appears as a small, CSF-intensity (hyperintense) cleft or cavity posterior to the third ventricle

  • Clearly delineates the pineal recess from surrounding brain parenchyma and pineal gland

T1-Weighted Images

  • Appears as a small, CSF-intensity (hypointense) area behind the third ventricle

  • Sometimes less conspicuous unless the surrounding tissue is contrasted (e.g., with gadolinium for tumor workup)

FLAIR

  • Typically null signal (dark) since FLAIR suppresses CSF signal

  • The pineal recess may appear as a hypointense area, similar to other CSF spaces

CT Appearance

  • Appears as a small, low-density (hypodense) area at the posterior margin of the third ventricle

  • Delineated by the pineal gland (sometimes calcified) and adjacent structures

  • May be difficult to visualize unless enlarged or if adjacent pathology is present

  • Occasionally seen as a thin cleft between the calcified pineal gland and third ventricle

MRI images

Pineal recess mri 3t sagittal image