II. Anatomy

  1. neuroCn3oculomotorGrayBB775.gif Lewis (1918) Gray's Anatomy 20th ed (in public domain at Yahoo or BartleBy)

III. Physiology

  1. Parasympathetic fibers follow Cranial Nerve III
    1. Innervates the ciliary Ganglion which in turn supplies sphincter pupillae and ciliaris muscles
    2. Parasympathetic impulses result in Pupil Constriction
    3. Uncal Herniation (Temporal LobeHerniation) compresses the third nerve
      1. Parasympathetic fibers are most susceptible to injury as they lie on the outside of CN III
      2. Parasympathetic fiber injury results in an ipsilateral pupil that is fixed/unresponsive and dilated
      3. With increasing pressure on Cranial Nerve III, complete oculomotor paralysis occurs
      4. Ultimately contralateral Cranial Nerve 3 involvement ensues
  2. Innervates five extrinsic eye muscles
    1. Levator palpebrae superioris
    2. Medial rectus
    3. Superior rectus
    4. Inferior rectus
    5. Inferior oblique

IV. Course

  1. Nucleii
    1. Nucleii are located in the floor of Cerebral Aqueduct at the level of the Midbrain
    2. Oculomotor Nucleus
      1. Origin of the eye somatic motor fibers that innervate five extrinsic eye muscles
      2. Subdivided into focus for each eye muscle
    3. Edinger-Westphal Nucleus
      1. Origin of the visceral motor fibers that innervate pupillary sphincter and ciliary muscles
      2. Slightly medial to the Oculomotor Nucleus
  2. Course
    1. As with all other Cranial Nerves (except CN 4), fibers remain ipsilateral (do not cross over)
    2. Nerve courses between Superior Cerebellar Artery and Posterior Cerebral Artery
    3. Forward and lateral to Posterior Clinoid process
    4. Cavernous Sinus lateral wall
    5. Enters orbit via superior orbital fissure

V. Exam

  1. Unilateral Pupil Paralysis (blown pupil or fixed, non-reactive dilated pupil):
    1. Increased Intracranial Pressure
    2. Subarachnoid Hemorrhage
  2. Oculomotor Nerve palsy with pupil sparing
    1. Seen as complication with Diabetes Mellitus

VI. 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

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Ontology: Oculomotor nerve structure (C0028864)

Definition (FMA) Cranial nerve which connects the midbrain to the extra-ocular and intra-ocular muscles.
Definition (UWDA) Cranial nerve which connects the midbrain to the extra-ocular and intra-ocular muscles.
Definition (NCI_CDISC) The third cranial nerve.
Definition (MSH) The 3d cranial nerve. The oculomotor nerve sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye. It also sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation. The motor fibers originate in the oculomotor nuclei of the midbrain.
Definition (CSP) third cranial nerve; sends motor fibers to the levator muscles of the eyelid and to the superior rectus, inferior rectus, and inferior oblique muscles of the eye; sends parasympathetic efferents (via the ciliary ganglion) to the muscles controlling pupillary constriction and accommodation; motor fibers originate in the oculomotor nuclei of the midbrain.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D009802
SnomedCT 56193007
English Nerve, Oculomotor, Nerves, Oculomotor, Oculomotor Nerve, Oculomotor Nerves, Cranial Nerve III, Cranial Nerve, Third, Cranial Nerves, Third, Nerve, Third Cranial, Nerves, Third Cranial, Third Cranial Nerve, Third Cranial Nerves, cranial nerve III, Oculomotor nerve [III], Nervus oculomotorius [III], Oculomotor nerve tree, cranial nerve iii, oculomotor nerves, cranial iii nerve, Cranial Nerve IIIs, third cranial nerve, 3n, oculomotor nerve, Nervus oculomotorius, OCULOMOTOR NERVE, Nervus Oculomotorius, Nerve IIIs, Oculomotorius, Nervus, Nerve III, Third cranial nerve, Oculomotor nerve, Cranial nerve III, Oculomotor nerve structure (body structure), Oculomotor nerve structure, Oculomotor nerve, NOS
French Troisième paire crânienne, Nerf oculomoteur, Nerf crânien III, Nerf moteur oculaire commun, Troisième nerf crânien, Nerf oculo-moteur, Nerf crânien 3
Swedish Ögonrörelsenerv
Czech nervus oculomotorius, okohybný nerv, III. hlavový nerv
Finnish Silmän liikehermo
Russian GLAZODVIGATEL'NYI NERV, TRETII CHEREPNOI NERV, ГЛАЗОДВИГАТЕЛЬНЫЙ НЕРВ, ТРЕТИЙ ЧЕРЕПНОЙ НЕРВ
German DRITTER HIRNNERV, Hirnnerv III, III. Hirnnerv, Nervus oculomotorius
Italian Nervo cranico III, Terzo nervo cranico, Nervo oculomotore
Croatian OKULOMOTORNI ŽIVAC
Latvian Acs kustību nervs
Polish Nerw okoruchowy, Nerw III
Japanese 動眼神経, 眼球運動神経, 第3脳神経
Norwegian 3. hjernenerve, Nervus oculomotorius, Øyets bevegelsesnerve, Okulomotorisk nerve, Hjernenerve 3
Spanish III Par Craneal, Nervio Craneal III, III par craneal, estructura del nervio oculomotor (estructura corporal), estructura del nervio oculomotor, nervio craneal III, nervio motor ocular, nervio oculomotor, tercer par craneal, tercer par craneano, III Nervio Craneal, Nervio Oculomotor, Tercer Nervio Craneal
Portuguese III Par Craniano, III Nervo Craniano, Nervo Craniano III, Nervo Oculomotor, Terceiro Nervo Craniano
Dutch IIIe hersenzenuw, Nervus cranialis III, Nervus oculomotorius

Ontology: Edinger Westphal nucleus (C0228416)

Definition (MSH) Nucleus in the oculomotor nuclear complex associated with oculomotor activities and stress adaptation.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D065839
SnomedCT 280162006, 62088007
English Parvocellular oculomotor nucleus, Accessory oculomotor nucleus, Oculomotor nucleus, parvocellular part, edinger-westphal nucleus, Edinger-Westphal nucleus of oculomotor nerve, parvocellular oculomotor nucleus, oculomotor nucleus, parvicellular part, oculomotor nucleus, parvocellular part, accessory oculomotor nucleus, PC3, Edinger Westphal nucleus, Nuclei accessorii nervi oculomtorii (Edinger-Westphal), Nucleus rostralis nervi oculomotorii, Nucleus Westphal-Edinger, Nucleus nervi oculomotorii Edinger-Westphal, Nucleus nervi oculomotorii parvocellularis, Edinger-Westphal nucleus (body structure), Edinger Westphal, Nucleus, Westphal, Nucleus Edinger, Nucleus Edinger Westphal, Edinger Westphal Nucleus, Edinger Westphals, Nucleus, Nucleus, Edinger-Westphal, Parvocellular Oculomotor Nucleus, Nucleus, Accessory Oculomotor, Edinger-Westphal Nucleus, Accessory Oculomotor Nucleus, Oculomotor Nucleus, Accessory, Westphals, Nucleus Edinger, Nucleus, Parvocellular Oculomotor, Oculomotor Nucleus, Parvocellular, Nucleus Edinger Westphals, Edinger Westphal nucleus (body structure), Edinger-Westphal nucleus
Spanish núcleo de Edinger - Westphal (estructura corporal), núcleo de Edinger - Westphal, núcleo de Edinger Westphal (estructura corporal), núcleo de Edinger Westphal

Ontology: Oculomotor nucleus (C0228686)

Definition (MSH) A collection of nuclei in the midbrain tegmentum for the OCULOMOTOR NERVE fibers.
Definition (CSP) somatic motor nucleus in the midbrain whose fibers enter the oculomotor nerve to supply the levator palpebrae muscle and all the extraocular eye muscles except the superior oblique and lateral rectus muscles.
Concepts Body Part, Organ, or Organ Component (T023)
MSH D065838
SnomedCT 59473007
English oculomotor nuclei, Set of oculomotor nuclei, Oculomotor nuclear complex, Oculomotor nuclei, Nucleus of oculomotor nerve, Nucleus of third cranial nerve, Oculomotor nuclei set, oculomotor nucleus, nucleus of oculomotor nerve, 3, oculomotor nuclear complex, Nucleus nervi oculomotorii, Nucleus oculomotorius, Oculomotor Nuclear Complex, Oculomotor Nucleus, Nervi Oculomotorii, Nucleus, Nuclear Complex, Oculomotor, Nucleus Oculomotorius, Nucleus Nervi Oculomotorius, Oculomotorius, Nucleus, Nucleus Nervi Oculomotorii, Nervi Oculomotorius, Nucleus, Nucleus, Oculomotor, Oculomotorii, Nucleus Nervi, Oculomotorius, Nucleus Nervi, Third cranial nerve nucleus, Oculomotor nucleus structure (body structure), Oculomotor nucleus structure, Oculomotor nucleus, nucleus nervi oculomotorii, nucleus oculomotorius
Spanish estructura del núcleo oculomotor (estructura corporal), estructura del núcleo oculomotor, núcleo del III par craneal, núcleo del nervio motor ocular, núcleo del tercer nervio craneal, núcleo del tercer par craneal, núcleo oculomotor