The three pairs of cranial nerves, motoneurotic (III), gliding (IV) and abducens (VI), are all motor nerves that innervate the eye muscles, and cranial injury can affect the extraocular muscles and the III, IV and VI pairs of cranial nerves and cause various forms of ocular muscle paralysis. So what are the specific possible causes? 1, cavernous sinus syndrome caused by cavernous sinus thrombosis or thrombotic cavernous sinusitis, often secondary to head and facial boils or sepsis, protrusion and fixation of the eyeball, dilated pupil, bulbar conjunctiva and orbital vicinity congestion and edema; can also appear optic papillary edema, vision loss or even complete blindness. If the cavernous sinus thrombosis is re-communicated or if collateral circulation is established, the protrusion of the eye may be significantly reduced. Thrombosis of one cavernous sinus may also spread through the cricoid sinus to the opposite cavernous sinus within a few days, resulting in symptoms on both sides. Inflammation in the cavernous sinus may also spread to nearby tissues causing meningitis, brain abscess, etc. The supraorbital fissure syndrome and supraorbital apical syndrome are manifested as III, IV, VI, V1 cranial nerve dysfunction without local inflammatory manifestations; if accompanied by orbital pain, it is called Tolosa-Hunt syndrome. Those with visual impairment are called orbital apical syndrome. It can be caused by local chronic infection. 3. Inflammation of the other motoneurones, talipes and abducens nerves can also cause paralysis of these nerves. When otitis media or combined chronic mastoiditis develops intracranially and destroys the tip of the rock bone, it causes dysfunction of the affected V and VI pairs of cranial nerves, which is called rock-tip syndrome or Gradenigo syndrome. Various types of skull base meningitis and encephalitis can cause oculomotor disorders.