Cranial Nerve Reflexes

  >   Rahul's Noteblog   >   Notes on USMLE facts, Exam Tips, and USMLE Lab Values   >   Cranial Nerve Reflexes

Ciliary reflex

Take a cotton swab and touch the ciliary body of the eye. If the patient doesn't blink, the patient has brain stem injury (fifth nerve nucleus is in the brain stem).

Deviating jaw:

Fifth nerve injured. Jaw deviates to paralyzed side.

Jaw reflex:

Ask the patient to open their mouth and then you tap on their chin gently; the jaw closing down powerfully signifies an upper motor neuron lesion of the fifth nerve.

Sixth nerve involvement:

The sixth nerve is the most common injured nerve because it has the longest pathway in the brain.

Patient cannot look to the sides:

Sixth nerve involvement.

Patient cannot look down:

Superior oblique muscle paralyzed.

Seventh nuclear involvement:

Supra-nuclear nerve involvement means a stroke; infra-nuclear nerve involvement means Bell's palsy. It is very important to differentiate between infra-nuclear and supra-nuclear seventh nerve involvement. If it is a supra-nuclear seventh nerve involvement, it is going to spare the upper of the face (only lower-half of the face involved). An infra-nuclear lesion will involve the whole face. Thus, forehead spared is supra-nuclear; forehead involved in infra-nuclear. Another way to differentiate is using the eyes. Ask the patient to close their eyes; if you can forcefully open the eyes, it is infra-nuclear; if you cannot forcefully open the eyes, it is supra-nuclear.

Regurgitation from the nose:

Tenth nerve involvement.

Shrug shoulders:

Test for eleventh nerve.

Patient sticks out tongue:

Twelfth nerve ok.

Deviations of tongue and jaw:

CN 5, 7, and 12 (PNP sandwich) cause deviations of any kind. CN 5 lesion causes mouth to deviate toward the paralyzed side; CN 7 lesion causes angle of the mouth to deviate toward normal side; CN 12 lesion causes tongue to deviate toward paralyzed side.

Additional Reading:

Random USMLE Facts

1. Random USMLE Facts volume 1-1
2. Random USMLE Facts volume 2-1
3. Random USMLE Facts volume 3-1
4. Random USMLE Facts volume 4-1
5. Random USMLE Facts volume 5-1
6. Random USMLE Facts volume 6-1
7. Random USMLE Facts volume 7-1
8. Random USMLE Facts volume 8-1
9. Random USMLE Facts volume 9-1
10. Random USMLE Facts volume 10-1
11. Random USMLE Facts volume 11-1
12. Random USMLE Facts volume 12-1

General and Systemic Examinations

1. General Examination for Internal Medicine
2. Jugular Venous Distention Workup
3. ER Chest Pain Workup
4. Format for Patient Presentation
5. Pulmonary Examination for Internal Medicine
6. Cardiac Examination for Internal Medicine
7. Abdominal Examination for Internal Medicine
8. Cranial Nerve Reflexes
9. Motor System Examination
10. Random Sensory System Facts
11. Random Stroke Facts

Medical Files & Presentations

1. USMLE Flashcards [Size: 1.9 MB; Format: MS Powerpoint]
2. Otitis Media in Children [Size: 5.4 MB; Format: MS Powerpoint]
3. Irritable Bowel Syndrome [Size: 170 kB; Format: MS Powerpoint]
4. Acid-Base Disturbance: Acidotic or Alkalotic? [Size: 427 kB; Format: PDF]
5. Thrombocytopenia [Size: 2.42 MB; Format: MS Powerpoint]
6. Are Face Transplants Ethical? [Size: 70.2 kB; Format: MS Powerpoint]

USMLE Step 2 CS Videos

1. Video of Cardiology Examination in a Clinical Setting
2. Video of Neurology Examination in a Clinical Setting
3. Video of Pulmonology Examination in a Clinical Setting
4. Video of Musculoskeletal Examination in a Clinical Setting
5. Video of Abdominal Examination in a Clinical Setting
6. Video of HEENT Examination in a Clinical Setting
7. Video and Description of Rinne Hearing Test
8. Video and Description of Weber Hearing Test

USMLE Laboratory (lab) Values

1. USMLE Blood Lab Values
2. USMLE Cerebrospinal Lab Values
3. USMLE Hematologic Lab Values
4. USMLE Sweat and Urine Lab Values

Medical Images

Useful Medical Images & Diagrams (link opens in a new window)

Random Pages:

Life in a Drop of Water Pictures of old Kuwaiti Dinars
Rahul`s Piano Music MP3 Collection Notes on Female Reproductive System
Notes on Lymph Nodes of the Axilla Notes on Rickettsia
Notes on Pyruvate Metabolism Notes on Statistical Research Methods
Stepwise Approach to Treatment of Ascites Notes on Endocrine Pancreas
Notes on Basic Gastrointestinal Physiology What is Time?
Why is it hard to find Christian husbands? What is an ELEK`s Test?
Why did I decide to become a doctor? Medical School Admissions Essay Video: Titanic Piano Theme: The Portrait
Corporate Failure: The Enron Case My Experience during the Iraqi Invasion of Kuwait
USMLE Blood Lab Values Regulation of Heart Rate by Autonomic Nervous System
Images of Antibodies What is Steady State Concentration?
Generalized vs Specialized Transduction Differentiation and Anatomy of a Blastocyst
Notes on Cell Components Notes on Nervous Tissue
Voices from Hell: My Experience in Mussoorie, India Video of Cardiology Examination in a Clinical Setting

Please Do Not Reproduce This Page

This page is written by Rahul Gladwin. Please do not duplicate the contents of this page in whole or part, in any form, without prior written permission.