Abducent nerve

6) Abducent nerve The longest cranial nerve (More prone to damage) Emerges from the groove between the lower border of the pons ...

6) Abducent nerve

• The longest cranial nerve (More prone to damage)
• Emerges from the groove between the lower border of the pons & the medulla oblongata
• Supplies the lateral rectus muscle
• Function is to turn the eye laterally

Examination of eye movements & pupils (Cranial nerve III, IV & VI)

Pupil	Dilated & become fix to light Consensual light reflex is absent in the affected eye
Ptosis	Eyelid droops over the eye (Also can be due to sympathetic lesion – Levator palpabrae has both skeletal & smooth muscle)
Ocular movements	Observe horizontal & vertical movements on 6 different directions of gaze Question the patient about Diplopia Example            : Diplopia is maximum when deviates to right & downwards (Right inferior rectus or Left superior oblique can be weak)
Conjugated movements	Check the ability to fix the gaze on one object (Ability of the eyes to move together)
Nystagmus	Disturbance in the normal balance of the eye control Need to check vertically & horizontally There’s a slow drift, followed by a fast corrective movement (Direction is given according to the fast phase)

Muscles involved in 6 different gazes