Page 28 - Demo

key differences between cranial nerve (CN) III (Oculomotor), IV (Trochlear), and VI (Abducens) palsies%u2022 CN III palsy can be partial or complete. In a complete palsy, all eye movements except abduction and intorsion are affected, and there's typically ptosis and pupil dilation.%u2022 CN IV palsy is often subtle and may present with compensatory head tilt to reduce diplopia.%u2022 CN VI palsy is the most common of the three, often seen in conditions that increase intracranial pressure.%u2022 In all cases, it's crucial to rule out serious underlying causes, particularly in acute onset palsies.Feature CN III Palsy CN IV Palsy CN VI PalsyAffected nerve Oculomotor nerve Trochlear nerve Abducens nervePrimary muscle affected Multiple: Medial rectus, superior rectus, inferior rectus, inferior oblique Superior oblique Lateral rectusEye position at rest \Slightly elevated and adducted Adducted (turned inward)Main movement deficit Limited adduction, elevation, and depression Difficulty looking down and in (inferonasally) Limited abduction (outward movement)Diplopia Vertical and horizontal Vertical, worse on looking down and to the opposite side Horizontal, worse on looking to the affected sideCompensatory head position Head tilt away from affected side Head tilt towards affected side and chin tucked Face turn towards the affected sidePupil involvement Often dilated and unreactive (if complete) Not affected Not affectedPtosis Present (if complete) Absent AbsentCommon causes Diabetes, aneurysm, trauma, tumor Trauma, congenital, tumor Increased intracranial pressure, trauma, tumorAssociated signs May have other neurological deficits if compressive lesion Rare isolated finding Can be associated with increased intracranial pressure