© Antoine Carron D.O., Nice, France 1
The Key to the Larynx
The laryngeal structure is supported by the hyoid bone, which acts as a cross-brace. This bone, free from any articulations, serves as a crossroad for myofascial tensions.
Various components of the suspension system exert their influence on it, which is then manifested in its dynamics.
The larynx is a complex organ composed of numerous cartilages and other functional elements. It is involved in three main functions: Breathing, speaking, and swallowing.[1]
Anatomy point
The larynx can be divided into three stages:
- The supraglottic level, delimited anteriorly by the epiglottis, posteriorly by the inter-arytenoid notch, laterally by the aryepiglottic folds, and below by the upper vocal cords.
- The glottic level, which contains the vocal cords that together delineate the glottic cleft. It also includes the two laryngeal ventricles (Morgagni’s ventricles) formed by an evagination of the mucosa.
- The infra-glottic level, corresponding to the opening of the trachea into the larynx.
It is composed of three unpaired cartilages:
- Epiglottic,
- Thyroid,
- and Cricoid.
And four paired cartilages:
- Corniculate,
- Arytenoid,
- Cuneiform (inconstant),
- Sesamoid (inconstant).
These various elements are connected by different membranes and muscles.
Swallowing Disorders or Dysphagia
The Hyoepiglottic Membrane or Ligament
This structure connects the inner part of the upper border of the hyoid bone to the anterior portion of the epiglottis.
It is an elastic connective tissue band that facilitates the proper movement of the epiglottis during swallowing
.
During its posterior tilt, the epiglottis is retained by the ligament and returned to a neutral position at the end of swallowing.
This membrane establishes a direct causal link between hyoid bone’s malposition and dysphagia without any alteration of tone.
In cases of dysphagia that do not improve with lingual rehabilitation, it may be interesting to assess hyoid traction, as its lateral components influence epiglottic mobility.
Case Study: Cervical Pain and Dysphagia
Mrs X, aged 27, consults for neck pain and discomfort when swallowing.
The patient describes a sensation of incomplete tracheal closure, particularly noticeable when drinking. She often coughs after drinking, triggered by the sensation of liquid entering the trachea.
The Symptoms began seven months ago after a horse-riding accident, which involved a lateral impact. During the fall, the helmet strap compressed her trachea.
All medical tests are negative.
A right lateral slippage of the hyoid bone was noted.
Following the treatment session, the dysphagia resolved completely.
It is important to note that four other structures involved in epiglottic stability can provide compensation and reduce the impact of certain hyoid dysfunctions on swallowing:
- Glosso-epiglottic ligaments, connecting the anterior surface of the epiglottic cartilage to the base of the tongue.
- Pharyngo-epiglottic ligaments, extending from the lateral edges of the epiglottis to the lateral wall of the pharynx.
- Thyro-epiglottic ligament, stretching from the lower end of the epiglottis to the thyroid cartilage.
- Aryepiglottic ligaments, spanning from the anterolateral surface of the arytenoid cartilage to the lateral border of the epiglottic cartilage.
Conversely, this means that the tongue, pharynx, and thyroid cartilage can also contribute to hyoid and epiglottic dysfunctions, potentially leading to dysphagia.
Phonation Disorders
Anatomy point
First, a breakdown of the key muscles involved:
Crico-thyroid muscles:
Responsible for elongating the vocal folds, increasing their tension.
Posterior crico-arytenoid muscles:
Induce abduction of the vocal ligaments.
Lateral crico-arytenoid muscles:
Induce adduction of the vocal ligaments.
Transverse and oblique arytenoid muscles:
Also create adduction of the vocal ligaments.
Vocal and thyro-arytenoid muscles:
Cause relaxation of the vocal ligaments.
These muscles, by determining the position of the vocal ligaments, cause a change in the shape of the glottic slit and thereby a modification in phonation. [2]
It should be noted that the crico-thyroid and thyro-arytenoid muscles are the two antagonistic muscles regulating vocal ligament tension. The first (crico-thyroid) is innervated by the external branch of the superior laryngeal nerve, while the second (thyro-arytenoid) is innervated by the recurrent laryngeal nerve.
A lower-pitched voice could therefore result from hypertonia of the crico-thyroid muscle caused by a malposition of the hyoid bone.
Conversely, a higher-pitched voice could be linked to hypofunction of the thyro-arytenoid muscle caused by the recurrent laryngeal nerve. This could be associated with a closure of the esophago-tracheal angle or restrictions in the passage zones of the vagus nerve.
This would result in an alteration of the various laryngeal mechanisms.
There are 4 laryngeal mechanisms [3][4][5]
The M0 Mechanism:
The vocal cords are short, thick, and loosely tensioned. The vibration is characterized by a very short glottic opening duration. This mechanism is responsible for the lowest frequencies. The fry voice is synonymous with this mechanism.
The M1 Mechanism:
Known as modal voice (or chest register), it involves the contraction of the thyro-arytenoid muscle, which shortens and thickens the vocal folds while maintaining a longer closure phase. This mechanism produces vibration of the entire vocal cord and is primarily involved in generating low frequencies.
The M2 Mechanism:
Known as modal voice (or chest register), it involves the contraction of the thyro-arytenoid muscle, which shortens and thickens the vocal folds while maintaining a longer closure phase. This mechanism produces vibration of the entire vocal cord and is primarily involved in generating low frequencies.
The M3 Mechanism:
Known as modal voice (or chest register), it involves the contraction of the thyro-arytenoid muscle, which shortens and thickens the vocal folds while maintaining a longer closure phase. This mechanism produces vibration of the entire vocal cord and is primarily involved in generating low frequencies.
Ligament of Phonation
The Jugal Ligament
It extends from the corniculate cartilages to the superior border of the cricoid plate.
This ligament could serve as an anatomical argument supporting recent discoveries that suggest a movement of the cricoid cartilage, sometimes accompanied by the arytenoid cartilages, in phonation rather than a movement of the thyroid cartilage.
The Vocal Cords
These are two symmetrical fibro-elastic bands forming the vocal folds.
They insert anteriorly to the inner angle of the thyroid cartilage, below the vestibular ligament, and posteriorly to the vocal process of the arytenoid cartilage. Their extremities may contain sesamoid cartilages known as glottic nodules.
As the main component of the vocal folds, they define an interspace called the glottic cleft, whose opening determines the phonatory outcome.
Phonation therefore depends on their mobility and position.
Innervation of the larynx
Anatomy point
The innervation of the larynx depends on the vagus nerve, or 10th cranial nerve. The inferior ganglion of this nerve gives rise to the superior laryngeal nerve at its lower pole.
This nerve divides into two parts: the upper part, called the “internal branch,” crosses the thyrohyoid membrane, which it perforates. It is responsible for innervating the mucosa of the epiglottis and the supraglottic portion of the larynx.
It is interesting to note that a portion of the nerve fibers from the internal branch anastomoses with the recurrent laryngeal nerve (also known as the inferior laryngeal nerve) through the Galen’s loop, innervating the pharyngeal portion of the larynx in the process. [6]
The lower part, called the “external branch,” runs along the insertion of the lower constrictor muscle of the pharynx along the thyroid cartilage. It reaches the crico-thyroid muscle, for which it provides innervation. It then enters the cricothyroid membrane and innervates the mucosa of the ventricles and the subglottic portion of the larynx.
In cases of superior laryngeal nerve neuralgia, there is a disturbance of the nerve’s sensory transmission. The patient experiences severe pain in the area of the thyroid cartilage and the gonion, which may even radiate toward the chest. This pain is triggered by mechanical stimulation of the area, such as swallowing or coughing.
The inferior laryngeal nerve, or recurrent laryngeal nerve, also originates from the vagus nerve. However, its origin differs slightly on the left and right due to the anatomical specifics of the two areas. [7]
On the left, it originates in the thorax, hooks around the lower portion of the aorta, and on the right, it originates at the base of the neck and hooks around the lower portion of the subclavian artery.
At the piriform recess, the two recurrent laryngeal nerves travel along the inner face of the inferior constrictor muscle of the pharynx, where they divide into two branches: one anterior and the other posterior, innervating all the muscles of the larynx, except for the crico-thyroid muscle (innervated by the external branch of the superior laryngeal nerve). The external branch of the superior laryngeal nerve and the recurrent laryngeal nerve are covered by the thyroid gland, which explains the impact of thyroid pathologies on laryngeal motility and phonation. [8]
Clinical Case
Mrs. P, 49 years old, consults for pain at the gonion with a sensation of blockage in the throat that either rises to the pharynx or descends to the clavicle.
She has difficulty initiating the swallowing motion and feels a lack of strength in her voice.
The anamnesis reveals significant anxiety and difficulty communicating the reasons for her discomfort.
Various medical examinations (thyroid, dental, etc.) are negative.
A release of the mediastinum, pharynx, and hyoid bone resulted in a 70% reduction in symptoms.
A release of the stomach using somato-emotional techniques addressed the remaining 30%
This portion of the meridian is associated with the stomach
Action musculaires
| Suprahyoid Muscle | Innervation | Action |
|---|---|---|
| Stylohyoid | Facial Nerve | Unilateral : Lateral flexion, rotation Bilateral : Posterior superior traction [9] |
| Hyoglossus | Hypoglossal Nerve | Tongue adaptation [10] |
| Geniohyoid | Hypoglossal Nerve | Anterior traction [11] |
| Mylohyoid | Trigeminal Nerve | Stabilization |
| Digastric Muscle | Glossopharyngien Nerve Facial Nerve Trigeminal Nerve | Elevation [12] |
| Infrahyoid Muscles | Innervation | Action |
|---|---|---|
| Pharyngeal Constrictor | Vagus Nerve | Constriction |
| Thyrohyoid | Cervical Plexus | Lowering |
| Sternohyoid | Cervical Ansa | Lowering |
| Omohyoid | Cervical Ansa | Lowering Posterior traction |
These different positions are therefore attributable to muscles or muscle groups and their innervation.
This table serves as an aid in treatment, with tissue traction diagnosis being the most suitable to perform positional listening.
Grip and Techniques
It is preferable to use the bilateral grip for tissue traction tests.
Bilateral Grip
This grip allows the practitioner to test or balance the tensions of the hyoid bone in all directions, including anterior and posterior movements, without prioritizing one side (which is more complicated with a unilateral grip).
The manipulation of the hyoid bone can be combined with phonation and swallowing exercises from the patient to refine the corrections of the patient’s hyoid mechanisms.
This work is particularly educational for professional singers.
A Lower Unilateral Grip
Its advantage is that it leaves the second hand free for harmonizing work on a second structure with a cephalic location.
The hypothenar eminence will serve as a fulcrum on the patient’s sternal manubrium.
Limits and biases
This grip tends to increase traction on one side, and if the fulcrum on the manubrium is not properly controlled, it will affect the mobility of the upper thoracic opening
Upper Unilateral Grip
Its advantage is that it leaves the second hand free for harmonizing work on a second, more caudal structure.
The middle finger acts as the fulcrum between the thumb and index finger. The elbow takes a fulcrum on the table. This grip tends to increase traction on one side.
Clinical Case
Mr. D, 55 years old, consults for upper back tension following a sore throat accompanied by bouts of coughing.
For the past two weeks, the cough has stopped, but the tension remains, and his throat still feels uncomfortable.
During the anamnesis, we identify that the sore throat started after a major argument at work.
The patient’s unresolved emotions are stagnating in the stomach (middle heater). A bilateral anterior dysfunction of the occiput is generating the back tension.
A tissue traction listening of the hyoid bone using a bilateral grip reveals a predominantly inferior traction.
A unilateral upper grip of the hyoid bone, combined with stomach balancing, results in the release of the patient’s emotions and allows for the expression of his previously unspoken feelings.
A second tissue listening of the hyoid bone with a bilateral grip reveals a superior-posterior traction (bilateral stylohyoid muscles with bilateral external rotation of the temporals in adaptation to an occipital flexion dysfunction).
A unilateral lower grip of the hyoid bone combined with occipital balancing completes the release of the upper back tension.
Emotional Point
Strong emotions like anger direct energy upwards. This energy needs to be expressed through shouting or crying. If this energy is withheld or not expressed, it becomes blocked at the level of the hyoid bone.
Point 23 of the Conception Vessel, called Clear Fountain, regulates the circulation of energy in this area.
The Huang Di Nei Jing Ling Shu [13] says: “If the energy rises with such intensity that one can no longer speak, and there is pain in the chest, the Lienn Tsivann (23 VC) should be punctured to disperse the energy of the Tsou Chao Inn meridian (kidneys).”
The functions associated with this point are: swelling at the base of the tongue, difficulty speaking, aphonia, sensation of energy rising, cough, ptyalism, and muteness. [14]
Antoine CARRON
Osteopath D.O.
Graduated from the Institute of Traditional Chinese Medicine
Bibliographie
[1] – Lacau St Guily J., Roubeau B. (1994) Voies nerveuses et physiologie de la phonation, Encyclopédie Médico-Chirurgicale, Oto-rhino-laryngologie ↩︎
[2] – Roubeau B. (1993) Mécanismes vibratoires laryngés et contrôle neuro-musculaire de la fréquence fondamentale, Thèse de doctorat de l’Université Paris-Orsay. ↩︎
[3] – Nathalie Henrich Bernardoni. Physiologie de la voix chantée: vibrations laryngées et adaptations phono-résonantielles. 40èmes Entretiens de Médecine physique et de réadaptation, (2012), Montpellier, France. pp.17-32. hal-00680692 ↩︎
[4] – Henrich N. (2006). Mirroring the voice from Garcia to the present day: Some insights into singing voice registers, Logopedics Phoniatrics Vocology, 31, 3-14. ↩︎
[5] – Roubeau B., Henrich N., Castellengo M. (2009). Laryngeal vibratory mechanisms: the notion of vocal register revisited. Journal of Voice, 23(4), 425−438. ↩︎
[6] – Dictionnaire médical de l’Académie de Médecine, https://www.academie-medecine.fr/le-dictionnaire/index.php?q=rameau+communicant+avec+le+nerf+laryng%C3%A9+r%C3%A9current ↩︎
[7] – Dictionnaire médical de l’Académie de Médecine, https://www.academie-medecine.fr/le-dictionnaire/index.php?q=nerf%20laryng%C3%A9%20r%C3%A9current. ↩︎
[8] – https://www.thyroidsymptoms.ca/fr-ca/hypothyroidism-symptoms/voix-rauque ↩︎
[9] – Magoun, H. Ostéopathie dans le champ crânien : édition originale 1951. (2011). ↩︎
[10] – Kendall, F. P., McCreary, E. K., & Provance, P. G. (1993). Muscles, Testing and Function : With Posture and Pain. http://ci.nii.ac.jp/ncid/BA51410885 ↩︎
[11] – Gehin, A. (2005). Atlas of Manipulative Techniques for the Cranium & Face (1st Edition). Churchill Livingstone. ↩︎
[12] – https://www.academiemedecine.fr/ledictionnaire/index.php?q=muscle+digastrique ↩︎
[13] – Le Huang Di Nei Jing se traduit par Classique interne de l’empereur Jaune, Il est le plus ancien ouvrage de médecine chinoise traditionnelle. Il est divisé en deux parties : le Su Wen et le Ling Shu. ↩︎
[14] – Nguyen Van Nghi. Huangdi Neijing Lingshu Volume 1: Books 1-3 with Commentary (2005), Jung Tao Productions. ISBN : 0980041708 ↩︎
- L’ostéo4pattes-site de l’ostéopathie remercie Antoine Carron pour nous avoir autoriser la publication de ses travaux. ↩︎