Trochlear nucleus

The trochlear nucleus is a small motor nucleus in the midbrain for the trochlear nerve

Gross Anatomy

The nucleus is located in the midbrain at the level of the inferior colliculus ventral and medial periaqueductal grey and dorsal to the medial longitudinal fasciculus. It lies just caudal to the oculomotor nucleus and Edinger-Westphal nucleus. The nucleus forms a longitudinal paramedian column of somatic motor nuclei along with the abducens, oculomotor and hypoglossal nuclei.

Trochlear efferent fibers leave the nucleus dorsally and laterally passing around the periaqueductal grey matter and descend medial to the mesencephalic nucleus where they decussate at the level of the superior medullary velum. The fibers emerge just caudal and lateral to the inferior colliculus.


The nucleus houses the motor cell bodies that innervate the superior oblique muscle in the orbit.

Anatomy: Brain

Anatomy: Brain

Article information

rID: 80958
Section: Anatomy
Synonyms or Alternate Spellings:

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: midbrain anatomy
    Drag here to reorder.
  • Figure 2: cranial nerve nuclei (illustration)
    Drag here to reorder.
  • Figure 3: brainstem motor nuclei - Gray's anatomy illustration
    Drag here to reorder.
  • Figure 4: brainstem nuclei: dorsal section - Gray's anatomy illustration
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.