Difference Between Right and Left Tympanic Membrane

The key difference between right and left tympanic membrane is that cone-shaped light reflection of the otoscope light is seen at the 4 o’clock to 5 o’clock position in the right tympanic membrane while cone-shaped light reflection of the otoscope light is seen at the 7 o’clock to 8 o’clock position in the left tympanic membrane.

Tympanic membrane (eardrum) is the membrane that separates the external ear from the middle ear. This membrane vibrates due to the incoming sound waves and conducts these vibrations to the tiny bones in the middle ear. It is a pearly gray, shiny and translucent membrane. It does not have bulging or retraction. Malleus is attached to the eardrum. It is one of the middle ear bones. Through the eardrum, the middle ear space can be seen, and a portion of the incus can also be identified. When the tympanic membrane is examined with an otoscope, the cone of light or light reflex is seen at the 4 o’clock to 5 o’clock position in the right tympanic membrane while it is seen at the 7 o’clock to 8 o’clock position in the left tympanic membrane.

CONTENTS

1. Overview and Key Difference
2. What is Right Tympanic Membrane
3. What is Left Tympanic Membrane
4. Similarities Between Right and Left Tympanic Membrane
5. Side by Side Comparison – Right vs Left Tympanic Membrane in Tabular Form
6. Summary

What is the Right Tympanic Membrane?

The right tympanic membrane or right eardrum is present in the right ear. When you examine inside the ear using an otoscope, you will be able to see the tympanic membrane. It consists of the lateral process of malleus, cone of light and pars tensa and pars flaccid. The cone of light is positioned at the 4 o’clock to 5 o’clock position in the right tympanic membrane.

What is the Left Tympanic Membrane?

The left tympanic membrane or left eardrum is present in the left ear. It consists of the lateral process of malleus, cone of light and pars tensa, and pars flaccid similar to the right tympanic membrane.

However, the cone of light is positioned at the 7 o’clock to 8 o’clock position in the left tympanic membrane.

What are the Similarities Between Right and Left Tympanic Membrane?

• Both right and left tympanic membranes are parts of the middle ear.
• These membranes vibrate from the incoming sound waves and transmit these vibrations to the tiny bones in the middle ear.
• They are thin, cone-shaped membranes.
• The rupture or perforations in both membranes can be lead to hearing loss.
• Perforations, tympanosclerosis, red and bulging membrane and retraction of the membrane are several signs that indicate abnormal right and left tympanic membranes.

What is the Difference Between Right and Left Tympanic Membrane?

The Cone of light is located in the 5 o’clock position when viewing a normal right tympanic membrane, while the cone of light is located in the 7 o’clock position for a normal left tympanic membrane. So, this is the key difference between right and left tympanic membrane. Besides, the right tympanic membrane is found in the right ear, while the left tympanic membrane is found in the left ear. Also, the right tympanic membrane separates the right external ear from its middle ear while the left tympanic membrane separates the left external ear from its middle ear.

Summary – Right vs Left Tympanic Membrane

The tympanic membrane is a thin, cone-shaped membrane that separates the external ear from the middle ear. Hearing loss is mainly due to the rupture or perforation in the tympanic membrane. In the right tympanic membrane, the light reflex is positioned at the 4 o’clock to 5 o’clock position while in the left tympanic membrane, the light reflex is positioned at the 7 o’clock to 8 o’clock position. Thus, this is the key difference between right and left tympanic membrane.

Reference:

1. “Cone of Light.” Wikipedia, Wikimedia Foundation, 23 Oct. 2020, Available here.
2. “Tympanic Membrane.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.

Image Courtesy:

1. “Normal Left Tympanic Membrane” By Madhero88 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Normal Left Tympanic Membrane” By Michael Hawke MD – Own work (CC BY-SA 4.0) via Commons Wikimedia