Commissure of Diencephalon (Posterior Commissure) (Commissura posterior)
Educational content only — not medical advice.
Anatomy
The commissure of the diencephalon (posterior commissure) is a rounded white matter band crossing the midline above the opening of the cerebral aqueduct. It transmits decussating fibers of the pupillary light reflex (connecting pretectal nuclei to bilateral Edinger-Westphal nuclei) and vertical gaze pathways.
Clinical notes
Pineal gland tumors compressing the posterior commissure produce Parinaud syndrome (dorsal midbrain syndrome), characterized by upward gaze palsy, light-near pupillary dissociation, and convergence-retraction nystagmus.
Related structures
Educational references
FAQ
What is the role of the Commissure of Diencephalon (Posterior Commissure)?
The commissure of the diencephalon (posterior commissure) is a rounded white matter band crossing the midline above the opening of the cerebral aqueduct. It transmits decussating fibers of the pupillary light reflex (connecting pretectal nuclei to bilateral Edinger-Westphal nuclei) and vertical gaze pathways.
Why is the Commissure of Diencephalon (Posterior Commissure) clinically important?
Pineal gland tumors compressing the posterior commissure produce Parinaud syndrome (dorsal midbrain syndrome), characterized by upward gaze palsy, light-near pupillary dissociation, and convergence-retraction nystagmus.
Source & license
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