MOUTH & TONGUE

how is the mouth divided

the mouth can be divided into the:

• vestibule - the sulci between the cheeks/ lips and the teeth

• oral cavity proper - the space inside the mouth and including the teeth

label the features of the vestibule

• lining mucosa - quite transparent, can often see blood vessels

outline the palatoglossal arch

• also known as the anterior pillars of fauces

• forms the boundary between the mouth and oropharynx

  • everything in front = mouth

  • everything behind = oropharynx

• extends from soft palate to the side of the tongue

• paired

outline the palatopharyngeal arch

• behind the palatoglossal arch

• also known as the posterior pillars of fauces

• extends from the soft palate to the side of the pharynx

where are the palatine tonsils situated

between the palatoglossal and palatopharyngeal arches

how can the uvula vary anatomically

• can be notched

• can be bifid

label the dorsal surface of the tongue

do circumvallate papillae contain taste buds?

yes

do filiform papillae contain taste buds?

no, they increase the surface area of the tongue

do fungiform papillae contain taste buds?

yes

label the ventral surface of the tongue

lining mucosa: non-keratinised

what do sublingual papillae contain

the opening of Wharton’s ducts (submandibular)

outline ankyloglossia

• commonly known as tongue-tie

• condition where the lingual frenulum is too short

• this restricts tongue movements

what are the two sets of muscles of the tongue

• extrinsic muscles

• intrinsic muscles

state the attachments and functions of the extrinsic muscles of the tongue

extrinsic muscles of the tongue

• attach to the skull and tongue

• changes the position of the tongue

state the attachments and functions of the intrinsic muscles of the tongue

intrinsic muscles of the tongue

• both attachments are within the tongue

• changes the shape of tongue

what are the extrinsic muscles of the tongue and which nerves supply their motor innervation

• genioglossus - CN XII (hypoglossal)

• palatoglossus - CN X

• styloglossus - CN XII (hypoglossal)

• hyoglossus - CN XII (hypoglossal)

what is the function of the genioglossus

• wide range of actions

• protrudes the tongue

• depresses the tongue

• deviates the tongue to the opposite side

what is the function of the palatoglossus

• elevates posterior tongue

• depresses the soft palate

what is the function of the styloglossus

• retracts tongue

• elevates the sides of the tongue

what is the function of the hyoglossus

• depresses tongue

• depresses the sides of the tongue

• retracts the tongue

what are the intrinsic muscles of the tongue and which nerves supply their motor innervation

• superior longitudinal

• inferior longitudinal

• transverse

• vertical

ALL INNERVATED BY CN XII (HYPOGLOSSAL)

what is the function of the superior longitudinal muscle

• shortens tongue

• curls apex and sides upwards

what is the function of the inferior longitudinal muscle

• shortens tongue

• curls apex downwards

what is the function of the transverse (lingual) muscle

• narrows tongue

• lengthens tongue

what is the function of the vertical (lingual) muscle

• broadens the tongue

• flattens the tongue

• elongates the tongue

which nerve(s) supply the tongue with motor innervation

• CN XII - hypoglossal

• CN X - vagus (palatoglossus)

which nerve(s) supply the tongue with sensory innervation

• CN IX - glossopharyngeal

• CN VII - facial nerve

  • chorda tympani branch

• CN V₃ - mandibular branch of trigeminal nerve

  • lingual branch

which region of the tongue does CN IX (glossopharyngeal) supply and what sensation is felt

• CN IX supplies sensory innervation to the posterior 1/3 of the tongue

  • taste sensation + general sensations e.g. heat, touch

what region of the tongue does CN VII (chorda tympani branch) supply and what sensation is felt

• CN VII (chorda tympani branch) supplies sensory innervation to the anterior 2/3 of the tongue

  • taste sensation

what region of the tongue does CN V₃ (lingual branch) supply and what sensation is felt

• CN V₃ (lingual branch) supplies sensory innervation to the anterior 2/3 of the tongue

  • general sensation e.g. heat, touch

describe the location of the chorda tympani in relation to the lingual nerve

• the chorda tympani fuses to the lingual nerve outside of the oral cavity

• the chorda tympani and lingual nerve therefore cannot be distinguished inside the tongue/ oral cavity

• the lingual nerve runs close to the mucosa that lines the floor of the mouth so it can be found easily if the oral cavity was dissected

describe oral masticatory mucosa

• tightly bound to the underlying bone

• midline of hard palate appears pale/ white

what do the arrows and red circle indicate

• red circle = oral cavity proper

what are the muscles of the soft palate

• levator veli palatini

• tensor veli palatini

• palatoglossus

• palatopharyngeus

what is the function of the pterygoid hamulus

• acts as a pulley for the tensor veli palatini

what is the function of the levator veli palatini

elevates soft palate

what is the function of the tensor veli palatini

tenses soft palate

what is the function of the palatoglossus

depresses soft palate

what is the function of the palatopharyngeus

depresses soft palate

what is the innervation of the muscles of the soft palate

all innervated by vagus, except the tensor veli palatini which is innervated by a branch of CN V₃

how are the auditory tube and levator and tensor veli palatini muscles associated

• the attachments of the levator veli palatini and to a degree the tensor veli palatini are important in terms of opening the Eustachian tube

• they attach closely to the opening of the auditory tube so when they contract, the auditory tube opens

• this is why in aeroplanes, chewing gum helps equalise the pressure in the ears

• the chewing action causes muscles of the soft palate to contract which opens the Eustachian tube

how does cleft palate affect the muscles of the soft palate and the health of the ear

children born with cleft palate have:

• weak action of TVP and LVP on the auditory tube because palatal attachment is ‘insecure’

• auditory tube does not open efficiently

• middle ear does not drain » ear infections

• middle ear does not drain » glue ear » conductive hearing loss

what related structure is commonly found near lymphatic vessels

blood vessels

which lymphatic vessels collect lymph from the lymphatic capillaries

two sets of lymphatic vessels collect lymph from the lymphatic capillaries:

• superficial - variable in distribution e.g. in the subcutaneous layer deep to the skin

• deep - larger, more constant vessels that accompany deep arteries and veins supplying skeletal muscles and organs

where are lymph nodes found

lymph nodes are found along lymphatic vessels and have a high concentration of lymphocytes

label the lymph nodes of the head and neck

• superficial cervical chain of nodes runs on top of sternocleidomastoid

where does the pre-auricular/ parotid lymph node receive lymphatic drainage from

• anterolateral scalp

• eyelids

• cheeks

where does the post-auricular lymph node receive lymphatic drainage from

• posterolateral scalp

where does the occipital lymph node receive lymphatic drainage from

• posterior scalp

• neck

where does the submandibular lymph node receive lymphatic drainage from

• face

• gingivae

• teeth

• tongue

» receives majority of lymphatic drainage from the oral cavity

where does the submental lymph node receive lymphatic drainage from

• central lower lip

• chin

• FOM

• tip of tongue

• incisor teeth

where does drainage from the occipital and post-auricular nodes pass to

the superficial cervical nodes and then to deep nodes

where does drainage from pre-auricular, submandibular and submental nodes pass to

the deep cervical nodes

where does lymph travel to from the deep cervical nodes

• from the deep cervical nodes lymphatic vessels form the right and left jugular trunks

• these empty into the right lymphatic duct (right side) or thoracic duct (left side)

diagram of intraoral lymphatic drainage

what introral structures do submental nodes drain

• lower anterior teeth

• central lower lip

• small area of FOM behind incisor teeth

• tip of tongue

what introral structures do submandibular nodes drain

• remaining lower dentition and supporting tissues

• remaining FOM

• lateral part of lower lip

• cheek

• upper lip

• upper anterior teeth

• anterior 2/3 of tongue

what introral structures do upper deep cervical nodes drain

• upper posterior teeth

• hard palate

• soft palate

where does the posterior 1/3 of the tongue drain into

directly into the jugulodigastric node of the deep cervical chain

where does the anterior 2/3 of the tongue drain into

• directly into the deep cervical nodes

• indirectly via the submental and submandibular nodes

where does the tip of the tongue drain into

submental nodes and then onto the jugulo-omohyoid node (deep chain)

what is the term for the vertical midline of the tongue

midline raphe/ lingual septum

outline the midline raphe/ lingual septum and its relationship to lymphatic drainage of the tongue

• forms an impervious lymph barrier that is deficient at the tip and posterior 1/3

• this means that drainage is bilateral at the tip and posterior 1/3 but ipsilateral for the remaining anterior 2/3

—

» lymphatic fluid cannot cross the raphe

what can often spread through lymphatic vessels

infections

how do lymph nodes respond to infection

• lymph nodes are placed at intervals in the lymphatic vessels

• they produce a response to infection by enlarging as they produce lymphocytes

what is the term used to refer to enlarged lymph nodes

lymphadenopathy - lymph nodes may be palpable when enlarged

describe the appearance of malignant cells

• malignant cells are usually atypical in appearance

• they lose their desmosomal attachments to each other

• they can therefore migrate

explain the association between cancer and lymphatic vessels

• malignant cells often migrate through lymphatic vessels into lymph nodes where they form secondary growths i.e. metastasise

• this is esp. true for head and neck cancers as other cancers spread through blood vessels instead

• the lymph nodes may also be palpable

image of oral squamous cell carcinoma (OSCC) with lymph node involvement