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EMSWORLD.com | APRIL 2016 47 other than the ability to clearly repeat the sentence and correctly identify the object is an abnormal response. Cranial Nerve Assessment Cranial nerves (CNs) are supplied by the posterior circulation of the brain. There are 12 nerves, but we routinely only test a frac- tion of them. Visual fields, CN II (optic nerve)—This controls the ability to see. To test for isolated strokes in the visual cortex of the brain or retina, face the patient and have them focus on your nose while they cover one eye with a palm. Hold one or two fingers up to both sides of the patient's face, where both of you should be able to see them in your peripheral vision. Ask the patient to identify how many fingers you're holding up on each hand or, alternatively, wave your fingers and ask the patient if they can see your fingers move on both sides. Repeat the test on the other eye. Some strokes will cause loss of vision just to one side of the peripheral field, and the patient may not even notice the loss without being tested. Note any complaint of vision loss or blurred or double vision. CN III (oculomotor)—Controls the pupil's response to light and is one of several nerves that allow movement of the eyes. The pupils are better assessed if they are slightly dilated. Therefore, whenever possible, pupils should be examined in an area that is dim but not too dark to see the eyes. Have the patient look straight ahead and note the size and shape of the pupils and how they react in response to light. Normally both pupils should constrict together. Pupils that are equal, round and reactive to light are said to be PERRL. Pupils should be of equal size (note size in mm). However, approx- imately 20% of the population has anisocoria (unequal pupil size). If both pupils respond to light, consider a pupil that is up to 1 mm larger than the other a normal variant. » Normal pupil size varies depending on the amount of light. In general, under normal lighting conditions, the pupils range from 3–5 mm. » Constricted (pinpoint) pupils of 1–2 mm are caused by bright light, opiates and other drugs. » Bilateral dilated pupils are generally greater than 5 mm. Causes include low light, sympathomimetics, hypoxia/anoxia, CO poison- ing, benzodiazepines and anticholinergic medications. » A unilateral dilated pupil in a patient who is conscious and alert is often caused by atropine drops. Occasionally a brain tumor can cause this as well. » A unilateral fixed and dilated pupil in an unresponsive patient is generally caused by increased intracranial pressure. This occurs when intracranial swelling compresses the third cranial nerve, which loses its ability to constrict the pupil. CNs III, IV, VI (oculomotor, trochlear, abducens)—Controls extra- ocular movements of the eyeball. Instruct the patient to focus on your finger and not move their head. Holding your finger at eye level and about a foot in front of the patient's face, move the finger *For terms and conditions please visit www.buyemp.com/customer-service.html BuyEMP.com You order. We ship (free). * It's that simple. • Large 3.5" Screen • 180° Swivel in Each Direction • High Resolution Camera & Display • Still Image & Video Recording • Video & Data Out Ports • Made in USA • Flexible Confgurations • Affordable - Great Value Contact EMP for more details 800.558.6270 Introducing the NEW 6630 Edge Plus Video Laryngoscope from IntuBrite ™ See The Difference For More Information Circle 37 on Reader Service Card