Muscles of the Tongue - Module 7

Tongue Divisions - Speech Articulation

Tip

Blade

Dorsum

Root

Body

Tip

Part closest to the front teeth at rest

Blade

Part just posterior to the tip and inferior to the alveolar ridge of the maxilla

Dorsum

Part posterior to the blade and below the back part of the hard palate

Top surface of the tongue

Root

Part that faces the back of the pharynx and

front of the epiglottis

Body

Central mass of the tongue that underlies

the surface features

Tongue Structures - Anatomy

Dorsum

Longitudinal median sulcus

Foramen cecum

Papillae

Longitudinal median sulcus

divides dorsum into right and left halves

Foramen cecum

small pit towards back of tongue

Papillae

projections of dermis covering tongue dorsum

give tongue rough texture

contain taste buds

Extrinsic muscles

Serve to anchor tongue, add to its bulk, aid in movement

Perform much of the gross movement of the tongue

Four extrinsic muscles

- Genioglossus

- Styloglossus

- Hyoglossus

- Palatoglossus

Genioglossus

Forms bulk of tongue tissue

Strongest and largest tongue muscle

Origin - mental spines of mandible

Course -

- lower fibers to hyoid bone

- remainder fan out to tongue dorsum

Insertion -

- hyoid

- submucosal fibrous tissue of tongue dorsum

Action -

- posterior fibers alone: draw tongue forward to protrude tip and press tip against teeth

- anterior fibers alone: may retract tongue tip

- all fibers together: pull tongue downward

Styloglossus

Small, fan-shaped muscle

Origin - styloid process of temporal bone

Course - inferior and anterior

Insertion -

- sides of tongue near dorsum

- some fibers blending with hyoglossus

Action -

- draw tongue posteriorly and superiorly

- may also create troughing

- antagonist to genioglossus

Hyoglossus

Origin - body and greater horn of hyoid bone

Course - vertical, diverging slightly

Insertion -

- lateral submucous tissue of posterior ½ of tongue

- some fibers continue in the palatoglossus

Action - retract and depress tongue

Palatoglossus

Same as Glossopalatine

- Name is reversed to emphasize that palate is fixed instead of tongue

Insertion

- Sides of tongue

Course

- Superior

Origin

- Lower surface of palatal aponeurosis, interdigitating with opposite fibers

Action - may exert upward pull on tongue if velum anchored

Intrinsic muscles

Tongue has two "skeletal" structures

- fibrous midline septum

- connective tissue "bag" just deep to epidermis

- provide attachment points for the intrinsic

muscles

Intrinsic muscles primarily responsible for

fine adjustment of the shape of the tongue

Four intrinsic muscles

- Superior longitudinal

- Inferior longitudinal

- Vertical

- Transverse

Superior Longitudinal

Thin layer of oblique and longitudinal fibers

Just below mucous membrane of dorsum

Origin - submucous fibrous tissue close to

tongue root, median fibrous septum

Course - anterior

Insertion - fibrous membrane at edges of

tongue

Action -

- shorten tongue

- turn tongue tip up

- unilateral: move tongue from side to side

Inferior Longitudinal

fibers lie on undersurface of tongue, lateral to genioglossus

Origin - root of tongue, some perhaps from hyoid bone

Course - anterior

Insertion - blend with other fibers from root to apex

Action -

- shorten tongue

- pull tongue tip down

Vertical

Origin - mucous membrane of tongue dorsum

Course - inferior and slightly lateral

Insertion - sides and inferior surface of tongue

Action - flatten tongue

Transverse

Origin - median fibrous septum

Course - lateral

Insertion - submucous fibrous tissue laterally

Action - narrow and elongate tongue

What are the tongues two "skeletal" structures?

fibrous midline septum

connective tissue "bag" just deep to epidermis

What are the extrinsic tongue muscles purpose?

largely responsible for the gross movement of the tongue (front, back, down)

What are the four extrinsic muscles?

Genioglossus

Styloglossus

Hyoglossus

Palatoglossus

What are the intrinsic tongue muscles purpose?

largely responsible for shaping and elevating the tongue

What are the four intrinsic muscles?

Superior Longitudinal Inferior Longitudinal

Vertical

Transverse