Location of the lesion | Associated symptoms/signs | Most common causes |
Nucleus | Complete ipsilateral third plus contralateral ptosis and contralateral superior rectus weakness | Infarction Hemorrhage Tumor |
Fascicles | Contralateral hemiparesis (Weber's syndrome) Contralateral tremor (Benedikt's syndrome) Ipsilateral ataxia (Nothnagel's syndrome) |
Infarction Hemorrhage Tumor Demyelination |
Subarachnoid space | Typically isolated May present with headaches or orbital pain |
ICA/Pcom A/Basilar/PCA Aneurysm Microvascular (ischemic) Tumor (pituitary, carcinomatous meningitis) Meningitis Herniation Trauma |
Cavernous sinus | Cranial nerves IV, VI, V1, V2 Oculosympathetic dysfunction (Horner) Pain may be prominent |
Tumor Inflammation Carotid aneurysm Microvascular (ischemic) Thrombosis Arteriovenous fistula |
Orbital apex | Proptosis Visual loss Cranial nerves IV, VI, V1, V2 Oculosympathetic dysfunction (Horner) Pain may be prominent |
Trauma Tumor Inflammation Infection (fungus) |