CN IV (TROCHLEAR)-C. COURSE

SUMMARY

1. The fibers (approximately 3,400) decussate dorsally to emerge below the inferior colliculus at the apex of the superior medullary vellum.

2. It then passes around the midbrain, below the edge of the tent to appear between the PCA and SCA.

3. It enters the roof of the cavernous sinus where the free and attached margins of the tentorium cross.

4. It is crossed medially by the CN III within the cavernous sinus.

5. It exits through the superior orbital fissure, above the Annulus of Zihn.



Image: Whitaker, R. and Borley, N. (2016). Instant anatomy. 6th ed. Chichester (West Sussex): Wiley Blackwell, p.93.

Reference(s)

R.M.H McMinn (1998). Last’s anatomy: regional and applied. Edinburgh: Churchill Livingstone. Get it on Amazon.
Drake, Richard L., et al. Gray's Anatomy for Students. Elsevier, 2023. Get it on Amazon.