Very Import MRCS Question Every Exam
There is one to two MRCS question every exam about eye Muscles and their Innervation,
that’s why you should be oriented about.
Oculomotor paralysis : due to
Pressure from herniating uncus on nerve; fracture involving cavernous sinus; aneurysms
The patient will have
Lost Pupillary Light Reflex
Mydriasis
Ptosis
Eye will be out and down
Due to unopposed action of
LR 6 ( Lateral Rectus by Abducens ) &
SO 4 ( Superior Oblique by Trochlear )
SO4 Trochlear nerve injury ; due Stretching of nerve during its course around brainstem
or Fracture orbit , the patient will not be able to look inferiorly when his eye is adducted
LR6 Abducens nerve injury ; due to long course of the nerve it is liable to injury in raised ICP causes ,
also in mastoiditis as it passes over petrous part of temporal bone , also in Fracture base of the skull
or Fracture involving cavernous sinusInability to rotate eye laterally; therefore when the diseased
eye tries to look laterally the patient will experience diplopia
As that eye couldn’t course laterally with healthy one.