The information in this section is summarised with permission from Scott McCoy’s wonderful book “Your Voice: An inside View – Multimedia Voice Science and Pedagogy”. (1)
There are approximately 33 muscles used in respiration, posture and phonation that need to be functioning at optimal levels for good breathing and phonation.
Source: Henry Gray, Anatomy of the Human Body, 1918
Primary muscles of ‘Inspiration’
External intercostal muscles
Internal intercostal muscles
Place your right hand on the left side of your rib cage and point it towards your hip. This is the direction of the muscle fibres of these muscles.
Secondary muscles affect localised parts of the breath mechanism but can still affect breath capacity. Postural muscles are very important – efficient breathing cannot occur if posture is compromised in any way.
(on the neck)
These muscles elevate the top of the rib cage aiding inhalation and help to turn the head.
(on the neck)
The scalenes stabilise and move the head but as they are attached to the top ribs they are also activated on inhalation to elevate the top of the rib.
Intercostals (Interchondral portion), pectoral muscles, subclavian and serratus anterior (on front of rib cage)
These muscles expand the top of the rib cage.
Trapezius/ levator scapulae
(upper back of the body)
Together these muscles raise the top of the rib cage increasing breath capacity.
(between the side border of the scapula and spine)
These are important muscles as they help maintain the ‘noble’ posture of singing (a non-collapsed sternum).
Serratus posterior/ erector spinae
(muscles which run up the spine)
These maintain a correct upright posture for singing.
(found in the deepest layer of the back)
These muscles help expand the upper back for breathing.
Innermost intercostals/ Transverse thoracis
These are small muscles that depress the front portion of the lower ribs for expiration.
(mainly a muscle that raises the arm)
These are large muscles on both sides of the body that aids compression of the back of the rib cage. Singers who rely on expansion in the middle and lower back must consciously relax these muscles during inhalation.
Serratus posterior inferior
These muscles help to depresses ribs 7-12.
Psoas major/minor muscles
(top of the leg)
These are important postural muscles that lift the leg and also tilt the pelvis. An incorrect pelvis position can compromise the ability of the abdominal muscles to function well in respiration.
In deep abdominal breathing the singer should aim to feel expansion right down at the level of the psoas (just above the hip), not just in the belly area.
Breath support and breath control
The amount of air taken in during inhalation and its pressure during exhalation is support; the rate at which air escapes the glottis [the area between the vocal folds], and therefore the maximum phrase duration can be sung, is control (McKinney, 1994).
A few interesting facts about the larynx
The length of vocal folds (strips of tissue running transversely on the horizontal plane from front to back in the neck): 18-23mm.
Intrinsic (internal) laryngeal muscles
These are activated by the nervous system i.e., if we think of what we want to sing, the muscles respond accordingly. We cannot voluntarily control these muscles. We can control the amount of breath that oscillates the folds, however, and this can affect the pitch. For example, if too much air is forced through the glottis the pitch will be sharp.
External laryngeal muscles
(muscles of the neck)
Many of the extrinsic muscles used in singing also have a function in swallowing. When we swallow, the larynx and hyoid bones ascend which helps fold the epiglottis over the airway so we don’t choke and send food down the airway.
Three extrinsic muscles are constrictors that wrap around the vocal tract and exert a downward squeeze when we swallow.
This is achieved by:
This muscle lifts the larynx towards the hyoid bone. Excessive tension in this muscle can lead to Muscular Tension Dysphonia and a chronic breathy sound.
These muscles raise the larynx and hyoid (posterior portion) and/or lower the jaw (anterior portion). If you have a tight over-extended jaw the anterior portion then becomes a laryngeal elevator leading to many problems for a singer.
This draws the larynx and hyoid bone up and back for swallowing.
Mylohyoid/ Geniohyoid Muscles
These form the musculature of the floor of the mouth: like the digastrics they drop the jaw and/or elevate the larynx.
The hyoglossus connects from the hyoid bone to the base of the tongue. Its function is to depress the tongue when swallowing but with certain tensions it too can elevate the larynx.
These are connected from the sternum to the base of the thyroid cartilage: contraction lowers the larynx. In singing, depressing this can lead to tension in the intrinsic muscles of the larynx so most teachers advocate just keeping these muscles free of tension so the larynx is anchored gently without actively pulling it down.
These connect the sternum to the hyoid bone and lower the larynx as do the Omohyoid muscles which also attach to the scapular. Shoulder tension can therefore affect the ability of the body to anchor the larynx.
For optimum singing the tongue must be free of tension in order to articulate vowels and consonants well and to produce the best possible resonance in the singing voice. The tongue attaches to the jaw, hyoid bone and soft palate. If there is tension or the jaw or hyoid bone are pulled out of alignment singing will be compromised.
There are many sites on the internet and wonderful anatomy books to increase your knowledge of how the body works for you as a singer. Please ask me for some recommendations.