• Home
  • Contact
  • Privacy Policy

All Medical Tests

Laboratory Tests

  • Carbs
  • Lipdis
  • Proteins
  • Biochemistry
  • Clinical techniques

Clinical Tests For Examination Of Oculomotor, Trochlear & Abducent Nerves

December 5, 2016 by Admin Leave a Comment

Third, Fourth & sixth Nerve Test:

They control ocular movements so considered together. They are mixed nerves. They bring sensations from proprioceptors in the eye muscles.

Fibers of these nerves take origin from a series of nuclei which begin in the floor of sylvian aqueduct and extending up to the fourth ventricle. Abducent nerve innervates the lateral (external) rectus muscle and trochlear innervates the superior oblique muscle. All other extra ocular muscles, the spincter pupillae muscles of accomodation and the levator palpebrae superioris are supplied by oculomoter nerve.

Role of extraocular muscles in movement of eye ball can be learn here.

Examination Of Oculomotor, Trochlear & Abducent Nerves

How to Test:

Look For Ptosis:

Drooping of upper eyelid.

Look for squint:

Abnormality of ocular movement in which axis do not meet at the point of fixation.

Nystagmus:

Involuntary rhythmic to and fro movement of eye ball.

Test for Ocular Movements:

Ask the subject to follow the movement of examiners finger with his eye in superior, medial, inferior, lateral and oblique directions. Stabilize the subject chin to prevent head movement. The examiner should observe that the movement of eye ball are smooth. If the full movement occurs, it is indicated that the muscles strength and nerve function is intact.

Examination of pupil:

Examine the size and shape of the pupil in both the eyes.

Check for pupillary reflexes i.e:

  • Light Reflex (direct as well as indirect/consensual)
  • Accommodation Reflex.

1. Light Reflex:

Direct Light Reflex:

It is done with the help of pen torch in dim light room. Each eye is examined separately. Ask the subject to see at a distant object. Through a bright light with the help of torch by bringing it from lateral side of the eye. Immediately observe the size of the pupil. Normally it should constrict.

Indirect/Consensual Light Reflex:

Project the light in one eye only and observe the response in other eye. In this reflex other eye also shows contraction of pupil. To prevent entry of light in other eye the hand is placed at the nose in between the eyes.

2. Accommodation Reflex:

When a person is asked to see a near object from distinct object, certain changes are taking place to see the near object clearly. These are:

  1. Increase in the power of the lens by contraction of ciliary muscles.
  2. Constriction of pupil which cause to decrease spherical and chromatic aberrations, intensity of light entering into the eye and to increase the depth of focus.
  3. Convergence of visual axis due to contraction of medial rectus muscle.

 

More from my site

  • Anthrone Test: A Quantitative analysis of CarbohydratesAnthrone Test: A Quantitative analysis of Carbohydrates
  • Iodine test for Starch- Its Principle, Reagents, Procedure etcIodine test for Starch- Its Principle, Reagents, Procedure etc
  • Collection of Blood: How and why is this done?Collection of Blood: How and why is this done?
  • Photoelectric Colorimeter: Working Principle, Use and ApplicationsPhotoelectric Colorimeter: Working Principle, Use and Applications
  • Spectrophotometer: Working Principle, Use and ApplicationsSpectrophotometer: Working Principle, Use and Applications
  • What Is PH Meter And How To Use It?What Is PH Meter And How To Use It?

Filed Under: Physiology Tagged With: abducent nerve examination, clinical examination, oculomotor, trochlear examination

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Archives

  • June 2017
  • April 2017
  • March 2017
  • February 2017
  • January 2017
  • December 2016
  • November 2016
  • October 2016

ABO and RH Blood Grouping

Our blood is classified into different blood groups and the basis for the differentiation between these groups are the substances such as antigens whose absence or presence determine a different blood group. Every blood group has its different plasma which is another base for differentiation in these blood groups. A person with one blood group […]

Differential Leukocyte Count Procedure And Results

You know from one of our previous articles that white blood cell count or total leukocyte count is a test which we perform to get the count of white blood cells in our blood. With the help of this test, we find the different ranges of leukocytes presiding in our body and if there are […]

Creatine Kinase Test by IFCC Kinetic Method:Principle, Procedure, Results

We have been doing different determinations by Kinetic UV method on our website. Today, our objective is the Creatine Kinase Test by IFCC Kinetic Method. Creatine kinase is basically an enzyme which is mostly present in heart muscles and skeletal. The formation of this substance happens which two subunits which are from muscle and brain […]

Osazone Test: Principle, Procedure, and Results

In the field of chemistry or medical sciences, one of the most common tests which is performed in biochemistry labs is Osazone Test. It is a normal routine test in order to identify the sugars. In this test, as the name indicates, osazones are involved and if you don’t about this substance, we will like […]

Lactate Dehydrogenase Test: Principle And Procedure

Before we estimate Lactate Dehydrogenase, we need to know why it is important. The reason for doing anything must be mentioned and that’s why need to know the reason first. Well, lactate dehydrogenase has many uses especially clinically. When tissue damage happens, the increase of this enzyme is one of the reasons behind it. This damage […]

Copyright © 2023 · Magazine Pro Theme on Genesis Framework · WordPress · Log in