CN IV Trochlear Nerve

Authors

Affiliations

Nathaniel Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

flowchart TB
  Lmidbrain[L Tegmentum of Midbrain] --> Decussate[Decussate]
  Decussate[Decussate] --> Ltrochlearnucleus[L Trochlear Nucleus]
  
  Ltrochlearnucleus --> LSOF[L Superior Orbital fissure]
  LSOF -- Somatic Motor --> LSOM{L Superior Oblique Muscle}
  

  RA[R tegmentum of the midbrain] --> Decussate[Decussate]
  Decussate --> Rtrochlearnucleus[R Trochlear Nucleus]
  Rtrochlearnucleus --> RSOF[R Superior Orbital fissure]
  RSOF -- somatic motor --> RSOM{R Superior Oblique Muscle}

Pathway

• Exits from the Tegmentum in the Dorsal Midbrain at the level of the inferior colliculus (Near midline & ventral to cerebral aqueduct)¹
• Trochlear nucleus
• (Decussate) & exit Midbrain ->cavernous sinus -> Superior orbital fissure -> Superior oblique muscle

Axons leave nucleus & Travel dorsally -> Decussate & Exit midbrain on dorsal surface -> Enter cavernous sinus -> Travel through superior orbital fissure -> Superior oblique muscle

References

1.

Blumenfeld H. Neuroanatomy Through Clinical Cases. 3rd ed. Oxford university press; 2022.