The Human Ear
The ear is a sensitive organ that serves functions such as hearing, equilibrium, and coordination. It has
been embellished with jewelry in every culture of the world symbolizing the true importance of the
hearing. Many diseases can affect our ears, some of them leading to hearing loss, balance disorders or
tinnitus. The human ear is made out of 3 three main parts: the outer, middle and inner ear.
The outer ear consists of the auricle, the most visible part which is directly linked to the tympanic
membrane through the external auditory canal. The role of the outer ear is to collect sound waves and
guide them to the eardrum. The auricle can be divided into three components: the helix, tragus, and
The sound travels a few centimeters through the auditory canal and it reaches the eardrum which is a
very sensitive membrane that vibrates.
The middle ear is an air-filled cavity that contains three small bones known as the ossicles(the malleus,
incus, and stapes). They are connected with each other through small synovial joints while being
suspended by ligaments and muscles with the purpose of mechanically amplifying the vibrations of the
tympanic membrane. The vibrations are transmitted to the Cochlea where they can be translated to
sound (C. S. Sinnatamby, 1999).
The ossicles chain ends up with the stapes’s footplate connection to the cochlea’s oval window, an
opening that’s covered in a membrane which leads from the middle ear to the vestibule of the inner ear.
As a link between the outer ear and the inner ear, the middle ear has two roles. ” One function is to
serve as an impedance-matching transformer that ensures an efficient transmission of sound energy”
( Y.T. Lin and W.H. Abdulaa, 2016, p 17).
The other purpose of the middle ear is to diminish the transmission of sound by muscle contraction, to
the cochlea. If these bone-conducted sounds were sent over to the cochlea they would appear very
loud, harming the inner ear.
The inner ear also known as the internal ear, converts the vibrations coming from the middle ear to
neural impulses which are sent to the brain. The main parts that constitute the inner ear are the
vestibular apparatus, which is the sensory system responsible for the perception of balance and spatial
orientation, and the cochlea, a spiral-shaped cavity that contains the organ of Corti.
The motion of the oval window, caused by the stapes, makes the fluids located in the cochlea to move,
resulting in the deformation of the basilar membrane as a response to the liquid pressure variation.
( Y.T. Lin and W.H. Abdulaa, 2016)
The basilar membrane is a flexible band, spiraling along the cochlea, that is oscillating (T. Reichenbach and A. J. Hudspeth, 2014).
The organ of Corti contains hair cells that will convert the movement of the basilar membrane to neural
Joseph E. Hawkings, (2017), ‘Human Ear’, Encyclopaedia Britannica, accessed at 20/1/2018, p. 1, available at: https://www.britannica.com/science/ear
Dr. Maxime St-Amant and A.Prof Frank Gaillard ,(2018) , ‘Middle Ear Ossicles’, Radiopaedia, accesed at 20/1/2018, available at: https://radiopaedia.org/articles/middle-ear-ossicles
Chummy S. Sinnatamby, (1999), ‘Last’s Anatomy: Regional and Applied (MRCS Study Guides)’, 10th Edn, Churchill Livingstone/Elsevier
Tobias Reichenbach and A.J. Hudspeth, (2014), ‘The physics of hearing: fluid mechanics and the active process of the inner ear’ Volume 77, number 7, IOP Publishing LTD
Yiqing Tina Lin, Waleed H. Abdulla (2015), ”Audio Watermark: A Comprehensive Foundation Using MATLAB, Switzerland, Springer International Publishing AG