ANATOMY OF THE VOCALS
THE
MYSTERY OF SOUND (TMS)
TMS May 6th 2017 Seminar
Material
THEME: VOCAL ANATOMY
TOPIC: ANATOMY OF THE VOCAL CORDS
INSTRUCTOR: EJE JOEL OMOJO
INTRODUCTION
Psalms
96:1 O sing unto the LORD a new song: sing unto the LORD, all the earth.
The
scripture above commands all earth to sing to the Lord a new song. Although all
creatures and creation produce sound in different ways to glorify God, human
begins sing with a structure called the vocal cords with a major support of the
larynx (voice box) to the vocal cords.
VOCAL CORDS
The vocal
cords are commonly known as the vocal folds or reeds but the most preferred
clinical name is called vocal cord: composed of twin in folding of mucus
membrane stretched horizontally from back to front across the larynx.
Vocal
cords are two folds of tissue which protrude from the sides of the larynx to
form a narrow slit (glottis) across the air passage.
Fig I
Diagram showing the vocal cords and its surrounding structures.
ACTION OF THE VOCAL CORDS
Open
during inhalation and comes together to close during swallowing / Phonation. When
closed the vibrate modulating the flow of air expelled through the lungs to
produce speech/singing. The folds of vocal cords are controlled by the Vagus
nerve (the 10th cranial nerve).
Their
controlled interference with the expiratory air flow produces audible
vibrations that makes your speech, song and other vocal noises.
The anatomy
of the vocal speaks clearly about its function in singing
LOCATION/STRUCTURE OF THE VOCAL CORD
The vocal
folds are located within the larynx at the top of the trachea. They are
attached posteriorly to the arytenoid cartilages, and anteriorly to the thyroid
cartilage. They are part of the glottis which includes the Rima glottidis.
Their outer edges are attached to muscle in the larynx while their inner edges,
or margins, are free forming the opening called the Rima glottidis. They are
constructed from epithelium, but they have a few muscle fibers in them, namely
the vocalic muscle which tightens the front part of the ligament near to the
thyroid cartilage. They are flat triangular bands and are pearly white in
color. Above both sides of the glottis are the two vestibular folds or false
vocal folds which have a small sac between them Situated above the larynx, the
epiglottis acts as a flap which closes off the trachea during the act of
swallowing to direct food into the esophagus. If food or liquid does enter the
trachea and contacts the vocal folds it causes a cough reflex to expel the
matter in order to prevent pulmonary aspiration.
Fig ii An image showing the location of the
vocal cord.
VARIATION IN VOCAL CORDS OF MALE/FEMALES
Males and
females have different vocal fold sizes. Adult male voices are usually lower
pitched due to longer and thicker folds. The male vocal folds are between 1.75
cm and 2.5 cm (approx. 0.75" to 1.0") in length, while female vocal
folds are between 1.25 cm and 1.75 cm (approx. 0.5" to 0.75") in
length. The vocal folds of children are much shorter than those of adult males
and females. The difference in vocal fold length and thickness between males
and females causes a difference in vocal pitch. Additionally, genetic factors
cause variations between members of the same sex, with males' and females'
voices being categorized into voice types.
A voice
type is a particular human singing voice identified as having certain qualities
or characteristics of vocal range, vocal weight, tessitura, vocal timbre, and
vocal transition point (passaggio ), such as breaks and lifts within the voice.
Other considerations are physical characteristics, speech level, scientific
testing, and vocal register.
LAYERS OF THE VOCAL CORD
*Histologically The
Human Vocal Cord Is A Laminated Structure Composed Of 5 Different Layers:
-the
vocalis muscle
-Main
body of the vocal cord is covers by a mucosa which consist of epithelium.
- the
lamina propria: consist of 3 layers. the most superficial layer consist of
loose collagen And elastic fibers and its loosely attached to the underlying
vocal ligament,an arrangement that produces a potential space (REINKE'S SPACE):
odema fluid readily collects here in disease: vocal abuse may initiate such but
this condition is confined to smokers.
Fig iii
showing the layers of the vocal cord. The Epithelium, the Lamina propria and
Vocalist muscle respectively.
Nerve
supply to the vocal cords: branches of the Vagus nerve (10th cranial nerve,):
superior/recurrent laryngeal nerve. Lesion to this nerve can cause paralysis
(in kinds) to the vocal cord.
Fig iv. Showing vocal
cord paralysis
The vocal cords consist of two mucosal folds: the
false folds (vestibular fold) and true folds. the false folds are not
responsible for sound production, but rather resonance... However exception of
it is found in some styles of singing. The false fold do not contain muscle
like the vocal cords dose.
Fig v showing the true fold and the false fold.
Effect of
Hormones on the Vocal cords
Studies
suggest that hormones play also an important role in vocal fold maturation.
Hormones are molecules secreted into the blood stream to be delivered at
different targeted sites. They usually promote growth, differentiation and
functionality in different organs or tissues. Their effect is due to their
ability to bind to intracellular receptors, modulating the gene expression, and
subsequently regulating protein synthesis. The interaction between the endocrine
system and tissues such as breast, brain, testicles, heart, bones, etc., is
being extensively studied. It has clearly been seen that the larynx is somewhat
affected by hormonal changes, but surprisingly, very few studies are working on
elucidating this relationship. The effect of hormonal changes in voice is
clearly seen when hearing male and female voices, or when listening to a
teenage voice changing during puberty. Actually, it is believed that the number
of hormonal receptors in the pre-pubertal phase is higher than in any other
age. Menstruation has also been seen to influence the voice. In fact, singers
are encouraged by their instructors not to perform during their pre-menstrual
period, because of a drop in their voice quality.
Estrogen,
androgen, and progesterone are hormones that contribute the structural changes
of the vocal cord.
Vocal Cords Hygiene for Singers.
Vocal cords exercises
Just like
an athlete maintains his or her muscles by regular training, so it is for the
vocal cords with vocal exercises to avoid damage to the vocal muscle (vocalis
muscle).
Singers
who don’t engage in vocal exercises may lack development of certain skills in
singing and cannot with stand pressure.
Vocal
Hydration
Hydration
is a necessity to enable vocal cords function properly.
The
lamina propria (made up of three layers) it’s a little more pliable than the
vocalist muscle. This allow for ease of vibration throughout the vocal cord. These
layers work together to create the vibratory characteristic of the voice. If
these tissues are dehydrated it is possible they loose their inherent vibratory
characteristics and changes the voice.
Intake of
dehydrating substance such as alcohol affects the hydration of the vocal cords.
Foods that
are highly acidic, have ability of eroding the epithelial lining of the vocal
cords.
These
foods can be avoided few weeks before a musical concert for proper preservation
of the vocal cords.
Examples
of acidic foods: citrus fruits, blue berries, etc.
•
•
Recommendations for further studies on this subject. - Vocal cancer
•
-
Reineike's Odema
•
-
Vocal cords nodules
•
-
Vocal paralysis
•
-
Foods that improve singing.
References
-Broaddus
Lawrence, Pamela Treole,Kathleen McCabe,Robert B etal., Journal of Voice, The
effect of preventive vocal hygiene habits and perceptual vocal characteristics
of training singers,2000, V.14,NO .1,pp .58-71.
-Gray
SD,Otolaryngologic Clinics of North America of the vocal folds,2000,V.30,No.4,
pp 98-679.
-Standring
Susan, Gray Henry, Gray Anatomy ,(2008), Edinbury: Churchill Livingstone
Elsevier,pp.583.
TMS Contact:
Elmond Isaiah
08067370005
07016606412
07016606412
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