Cranial Nerve 6


Cranial Nerve 6, Cranial Nerve VI, Abducens Nerve, CN 6, Abducens Nucleus

  • Physiology
  1. Innervates extraocular lateral rectus muscle
  2. Moves eye laterally
  3. Long thin nerve that is susceptible to compression (Cranial Nerve 4 and 6 are similar in this way)
    1. Paralysis (unilateral or bilateral) may occur even with generalized Increased Intracranial Pressure
    2. Contrast with the Cranial Nerve 3 which is a thick cable-like nerve requiring significant compression for paralysis
  • Anatomy
  1. Abducens Nucleus
    1. Abducens Nucleus lies beneath facial colliculus in the pons
  2. Course
    1. As with all other Cranial Nerves (except CN 4), fibers remain ipsilateral (do not cross over)
    2. Nerve runs below clinoid process
    3. Nerve passes through Cavernous Sinus
    4. Enters orbit through superior orbital fissure
  • Exam
  1. Normal function of the lateral rectus muscle
    1. Lateral eye movement (eye abduction)
  2. Paralysis of the lateral rectus muscle
    1. eye_eom.png
    2. See Cranial Nerve 6 Palsy
    3. Unilateral paralysis results in lateral Gaze Palsy (may present with horizontal Diplopia)
    4. Bilateral paralysis seen in Botulism
  • References
  1. Gilman (1989) Manter and Gatz Essentials of Neuroanatomy and Neurophysiology, Davis, p. 87-113
  2. Goldberg (2014) Clinical Neuroanatomy, p. 24-39
  3. Netter (1997) Atlas Human Anatomy, ICON Learning, p. 110-129