Chapter 7: Cranial Nerves LAB

Name: ______

Date: ______Period: ____

Chapter 7: Cranial Nerves LAB

Sports Medicine Athletic Training

Purpose: To identify and explore the functions of each cranial nerve in order to understand them better and to learn how a head injury can make them function abnormally. We as humans have a central computer that controls all of our life functions, it’s called the brain. As athletic trainers, we need to be able to protect the brain and our athletes. When an athlete sustains an impact to the head, we need to be able to rule out several factors and be able to identify a concussion quickly and as accurately as possible. In doing so, we will assess several aspects of the brain, its functions and the severity of the injury.

Cranial Nerves

We have 12 cranial nerves that control our motor and sensory information. To help establish, without the use of a CT scan, where the brain injury has occurred we will test these cranial nerves and their functions. The cranial nerves are in orders from anterior to posterior starting in the frontal lobe of the brain.

I.  Olfactory

·  Controls the sense of smell

·  Most frontal CN that resides in the frontal lobe

·  To Test: Have the athlete close their eyes and smell something. Then ask them to identify what they smell as soon as they smell it.

II.  Optic

·  Controls visual acuity and field.

·  To Test: Ask the athlete how many fingers you are holding up. Then ask them to look straight ahead and tell you when they see your fingers as you approach from the back of the head around to the front from the side. When they tell you that they see your fingers around the side, without shifting their eyes, using their peripheral vision, identify how many fingers are in place.

III.  Occular motor

·  Controls Pupillary Reflexes

·  To Test: Use the pen light to shine into the athletes eyes. Watch the pupil constrict when the light shines into the eye. Check the other eye to check for symmetry. If one is dilated or sluggish, there may be some brain trauma.

IV.  Trochlear

·  Controls eye movement.

·  To Test: Have the athlete follow the finger up and down and holding it close to their face.

V.  Trigeminal

·  Controls Facial sensations

·  To Test: Have the athlete close their eyes. Instruct them that when they feel you touching them, to identify where you are touching them on the face.

VI.  Abducens

·  Controls Lateral Eye Movement

·  To Test: Have the athlete follow your finger side to side and up and down. A normal test would be a smooth fluid tracking of the finger without moving their head.

VII.  Facial

·  Controls facial motor skills and taste

·  To Test: Facial motor skills are tested by having the athlete smile and then wrinkle their forehead. Taste is by having the athlete identify the taste something like gum.

VIII.  Vestibulochochlear (Acoustic)

·  Controls Hearing and Balance

·  To Test Hearing: Have the athlete close their eyes and identify a sound

·  To Test Balance: Rhomberg’s Test (standing with feet together, arms outstretched and eyes closed). Also finger to nose test, heel to toe walking, heel to knee standing, and touching ATC’s finger rapidly in several areas.

IX.  Glosopharyngeal

·  Controls swallow reflex

·  To Test: ask the athlete to swallow, open their mouth and say “Ahhh”

X.  Vagus

·  Controls Gag reflex

·  To Test: Have athlete swallow

XI.  Spinal Accessory

·  Controls Head / Neck strength

·  To Test: Have the athlete shrug their shoulders and apply resistance to their shoulders. Then have them rotate their head and test the strength of the neck flexors, extensors, rotation, and side bend.

XII.  Hypoglossal

·  Controls tongue movement and strength

·  To Test: apply tongue resistance with a tongue blade side to side and up and down.

Cranial Nerves Evaluation

Cranial Nerve Number and Name / What function(s) does this nerve Control? Is it Sensory, Motor or Both? / How did you test it? Why did you test it this way? / What was the normal response?
I
______
II
______
III
______
IV
______
V
______
VI
______
VII
______
VIII
______
IX
______
X
______
XI
______
XII
______

POST LAB QUESTIONS:

1.  What 3 cranial nerves control eye movement? ______

2.  If the pupils are uneven, one dilated and the other constricted when light enters the eye, what could one determine from that observation? ______

3.  What is the difference between a mixed cranial nerve and a sensory cranial nerve? ______

4.  ______bathes the brain and spinal cord in chemicals for proper functioning, helps maintain regular pressure around the brain and spinal cord, and protects the brain from impacts.

5.  Where is CSF found in the brain and spinal cord? ______

6.  Where is CSF formed? ______

7.  List the 3 Meninges of the Brain: ______

8.  Describe Post-concussion Syndrome: ______

9.  Describe and define Second-Impact Syndrome: ______

10.  What would you do if you were to hear that an athlete who was cleared to play by the doctor and the ATC, because the athlete lied about their symptoms being all resolved, but was still having headaches? ______