Pharynx & Pharyngeal Muscles - Module 7

Velum Muscles

Velum Muscle Actions

Pharynx

An oval tube, larger side to side then front to back

Connective tissue

predominates at the top;

muscle predominates at

the bottom

Continuous with

esophagus at lower end

Pharynx

Three cavities

Lower boundaries are level of hard palate

(nasopharynx), hyoid bone

(oropharynx), and base of

the cricoid cartilage

(laryngopharynx)

Nasopharynx contains the

auditory tubes and

nasopharyngeal tonsils

(adenoids)

Pharynx

Opening of oropharynx is

through the faucial isthmus

(bounded by anterior

faucial pillars)

Oropharynx contains the

palatine tonsils and lingual

tonsil

Pharynx

Pharyngeal tube has 3 layers

- Fibrous layer (aponeurosis)—predominately in upper part of pharynx

- Muscular layer

- Mucous layer

Aponeurosis attached to base of skull anterior to foramen magnum

- Pharyngeal muscles attached to this aponeurosis

3 pairs of muscles, referred to as constrictors

Action of each is to reduce the diameter of a portion of the pharyngeal cavity

Superior Constrictor Description

Weakest, but most complex of the three

Forms nasopharyngeal and upper

oropharyngeal walls

Origin - sphenoid, mandible, pterygomandibular ligament

Course - posterior, then medial

Insertion - midline raphe

Action - may contribute to velopharyngeal closure by moving posterior wall of pharynx

anteriorly

Superior Constrictor Figure

Middle Constrictor Description

Somewhat fan shaped

Origin - hyoid bone

Course - fan out posteriorly and medially

Insertion - midline raphe

Action - reduce diameter of pharynx

Middle Constrictor Figure

Inferior Constrictor -

Thyropharyngeus Description

Inferior Constrictor consists of the

Thyropharyngeus and the Cricopharyngeus

Inferior Constrictor is thickest and strongest of constrictor muscles

Thyropharyngeus is the majority of the Inferior Constrictor

Origin -thyroid cartilage

Course - fans out posteriorly and medially

Insertion - midline raphe

Action - reduce diameter pharynx

Inferior Constrictor -

Thyropharyngeus Figure

Inferior Constrictor -

Cricopharyngeus Description

Part of Inferior constrictor

Muscular component of upper esophageal

sphincter (UES)

Origin - cricoid cartilage

Course - fans out posteriorly and medially

Insertion - midline raphe

Action - open and close upper esophageal

sphincter

Inferior Constrictor -

Cricopharyngeus Figure

Constrictor Muscle Actions

Constrictor muscles all pull pharyngeal

walls inward and forward to constrict

the pharyngeal tube

Cricopharyngeus also assists in closing

the upper esophageal sphincter

Stylopharyngeus Description

Long thin muscle

Origin - styloid process of temporal bone

Course - inferior, entering between

superior and middle constrictor

Insertion - blend with constrictors, with

some fibers inserting on thyroid cartilage

Action - elevate and dilate pharynx

Stylopharyngeus Figure

Salpingopharyngeus Description

Short thin muscle

Origin - lower border of the pharyngeal

orifice of the Eustachian tube

Course - inferior, deep to superior

constrictor

Insertion - blends with fibers of palatopharyngeus muscle

Action - elevate and dilate pharynx

Salpingopharyngeus Figure

Palatopharyngeus Description

Also known as Pharyngopalatine

Posterior faucial pillar

- Longer muscle

Origin

- Soft palate

Course

- Superior through posterior faucial pillar

Insertion

- Lateral walls of pharynx, thyroid cartilage

Action

- Principally to guide material through pharynx

- May contribute to palatal lowering

- May contribute to VP seal

Palatopharyngeus Figure

What is the purpose of the pharyngeal muscles?

Constrict (reduce the diameter) of the pharynx

What are the three major muscles?

Superior

Middle

Inferior - divided into Thyropharyngeus and Cricopharyngeus

What is the purpose of the Cricopharyngeus?

Helps to close the Upper Esophageal Sphincter

What is the purpose of the Stylopharyngeus and Salpingopharyngeus?

Elevate and dilate (increase the diameter) of the pharynx