Habenular Trigone

The habenular trigone is a small depressed triangular area situated in front of the superior colliculus and on the lateral aspect of the posterior part of the taenia thalami.

It contains a group of nerve cells termed the ganglion habenulæ.

Fibers enter it from the stalk of the pineal body, and others, forming what is termed the habenular commissure, pass across the middle line to the corresponding ganglion of the opposite side.

Most of its fibers are, however, directed downward and form a bundle, the fasciculus retroflexus of Meynert, which passes medial to the red nucleus, and, after decussating with the corresponding fasciculus of the opposite side, ends in the interpeduncular ganglion.

This article incorporates text from a public domain edition of Gray's Anatomy.

Human brain: diencephalon (TA A14.1.08, GA 9.807)
Epithalamus
Surface
  • Pineal body
  • Habenula
  • Habenular trigone
  • Habenular commissure
Grey matter
  • Pretectal area
  • Habenular nuclei
  • Subcommissural organ
Thalamus
Surface
  • Stria medullaris of thalamus
  • Thalamic reticular nucleus
  • Taenia thalami
Grey matter/
nuclei
  • paired: AN
  • Ventral
    • VA/VL
    • VP/VPM/VPL
  • Lateral
    • LD
    • LP
    • Pulvinar nuclei
  • Metathalamus
    • MG
    • LG
  • midline: MD
  • Intralaminar
    • Centromedian
  • Midline nuclear group
  • Interthalamic adhesion
White matter
  • Mammillothalamic fasciculus
  • Pallidothalamic tracts
    • Ansa lenticularis
    • Lenticular fasciculus
    • Thalamic fasciculus
  • PCML
    • Medial lemniscus
    • Trigeminal lemniscus
  • Spinothalamic tract
  • Lateral lemniscus
  • Dentatothalamic tract
  • Acoustic radiation
  • Optic radiation
  • Subthalamic fasciculus
  • Anterior trigeminothalamic tract
  • Medullary laminae
Hypothalamus
Surface
  • Median eminence/Tuber cinereum
  • Mammillary body
  • Infundibulum
Grey matter
Autonomic zones
  • Anterior (parasympathetic/heat loss)
  • Posterior (sympathetic/heat conservation)
Endocrine
  • posterior pituitary: Paraventricular
    • magnocellular
    • parvocellular
  • Supraoptic
    • oxytocin/vasopressin
  • other: Arcuate (dopamine/GHRH)
  • Preoptic (GnRH)
  • Suprachiasmatic (melatonin)
Emotion
  • Lateral
  • Ventromedial
  • Dorsomedial
White matter
  • afferent
    • SN → Medial forebrain bundle
  • efferent
    • Mammillothalamic fasciculus → AN, Stria terminalis → Amygdala, Dorsal longitudinal fasciculus → SC
Pituitary
  • Posterior is diencephalon, but anterior is glandular
Subthalamus
  • Subthalamic nucleus
  • Zona incerta
Ventricular system:
Third ventricle
  • recesses:
    • Optic recess
    • Infundibular recess
    • Suprapineal recess
    • Pineal recess
  • Hypothalamic sulcus
  • Tela chorioidea of third ventricle
  • Subfornical organ
  • Apertures: Interventricular/Monro
  • Posterior commissure

M: CNS

anat (n/s/m/p/4/e/b/d/c/a/f/l/g)/phys/devp

noco (m/d/e/h/v/s)/cong/tumr, sysi/epon, injr

proc, drug (N1A/2AB/C/3/4/7A/B/C/D)