Anatomy of oral cavity, pharynx& larynx-Dr Rajesh Kumar

DR. RAJESH KUMARATRCTRI, BIKANER

ORAL CAVITY

PHARYNX

LARYNX

Oral Cavity (mouth) The entire oral cavity is lined with mucous

membrane tissue. The oral cavity consists of the following two areas:

1. The vestibule is the space between the teeth and the inner mucosal lining of the lips and checks.

2. The oral cavity proper is the space contained within the upper and lower dental arches.

Oral Cavity (Mouth) Extends from the lips to the

oropharyngeal isthmusThe oropharyngeal isthmus:

Is the junction of mouth and pharynx.

Is bounded: Above by the soft palate and

the palatoglossal folds Below by the dorsum of the

tongue Subdivided into Vestibule &

Oral cavity proper

The DentitionsThe term dentition is used to describe the

natural teeth in the jawbones.Primary dentition is the first set of 20 primary

teeth. Also referred to as “baby teeth” or “deciduous teeth”

Permanent dentition refers to the 32 secondary or “adult” teeth.

Mixed dentition occurs when both primary and permanent teeth are present, usually between the ages of 6 to 12.

Dental archesThe maxillary arch (upper arch), actually part of the

skull, is fixed and not capable of movement. The teeth in the upper arch are set in the maxilla, the maxillary bone.

The mandibular arch (lower arch) is capable of movement through the action of the temporomandibular joint. The mandible, the mandibular bone supports the teeth in the lower arch.

Eruption & ExfoliationEruption is the movement of the tooth through the

surrounding tissues so that more of the tooth becomes visible in the mouth.

Exfoliation is the process by which the roots of the baby tooth are resorbed and dissolved until so little root remains that the baby tooth falls out.

Vestibule Slitlike space between the

cheeks and the gums Communicates with the

exterior through the oral fissure

When the jaws are closed, communicates with the oral cavity proper behind the 3rd molar tooth on each side

Superiorly and inferiorly limited by the reflection of mucous membrane from lips and cheek onto the gums

Vestibule cont’d The lateral wall of the

vestibule is formed by the cheekThe cheek is composed

of Buccinator muscle, covered laterally by the skin & medially by the mucous membrane

A small papilla on the mucosa opposite the upper 2nd molar tooth marks the opening of the duct of the parotid gland

Oral Cavity Proper

It is the cavity within the alveolar margins of the maxillae and the mandible

Its Roof is formed by the hard palate anteriorly and the soft palate posteriorly

Its Floor is formed by the mylohyoid muscle. The anterior 2/3rd of the tongue lies on the floor.

hard

soft palate

mylohyoid

Floor of the Mouth Covered with mucous

membrane In the midline, a mucosal

fold, the frenulum, connects the tongue to the floor of the mouth

On each side of frenulum a small papilla has the opening of the duct of the submandibular gland

A rounded ridge extending backward & laterally from the papilla is produced by the sublingual gland

Nerve Supply

o Sensory Roof: by greater palatine and nasopalatine nerves

(branches of maxillary nerve) Floor: by lingual nerve (branch of mandibular nerve) Cheek: by buccal nerve (branch of mandibular nerve)

o Motor Muscle in the cheek (buccinator) and the lip (orbicularis

oris) are supplied by the branches of the facial nerve

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The tongue is a mobile muscular organ can assume a variety of shapes and posit ions. The tongue is partly in the oral cavity and partly in the pharynx.

At rest i t occupies essential ly al l the oral cavity proper.

TONGUE

Tongue Mass of striated muscles

covered with the mucous membrane

Divided into right and left halves by a median septum

Three parts:Oral (anterior ⅔)Pharyngeal (posterior ⅓)Root (base)

Two surfaces:Dorsal Ventral

Intrinsic Muscles: Intrinsic muscles represent the substance of the tongue. They are responsible for the tongue’s ability to change shape.

Extrinsic Muscles: Extrinsic muscles originate at sites like the hyoid bone, the styloid process of the temporal bone, and the genial tubercles. The extrinsic muslces proceed from their sites of origin and insert into the tongue’s mass. The extrinsic musculature enables the mass of the tongue to move from place to place within the mouth. Intrinsic and extrinsic muscles do not act in isolation from one another. The smooth, precise tongue movements that we take for granted are the result of finely coordinated contractions generated by appropriate muscles in both groups.

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Palate Lies in the roof of

the oral cavity Has two parts:

Hard (bony) palate anteriorly

Soft (muscular) palate posteriorly

hard

soft palate

Hard Palate Lies in the roof of the

oral cavity Forms the floor of the

nasal cavity Formed by:

Palatine processes of maxillae in front

Horizontal plates of palatine bones behind

Bounded by alveolar arches

Hard Palate

Posteriorly, continuous with soft palate

Its undersurface covered by mucoperiosteum

Shows transverse ridges in the anterior parts

Soft Palate Attached to the posterior

border of the hard palate Covered on its upper and

lower surfaces by mucous membrane

Composed of:Muscle fibersAn aponeurosisLymphoid tissueGlandsBlood vesselsNerves

Muscles Tensor veli palatini

Origin: spine of sphenoid; auditory tube Insertion: forms palatine aponeurosisAction: Tenses soft palate

Levator veli palatiniOrigin:petrous temporal bone, auditory

tube, palatine aponeurosis Insertion: palatine aponeurosisAction: Raises soft palate

Musculus uvulaeOrigin: posterior border of hard palate Insertion: mucosa of uvula Action: Elevates uvula

MusclesPalatoglossus

Origin: palatine aponeurosis Insertion: side of tongueAction: pulls root of tongue

upward, narrowing oropharyngeal isthmus

PalatopharyngeusOrigin: palatine aponeurosis Insertion: posterior border of

thyroid cartilageAction: Elevates wall of the

pharynx

Sensory Nerve SupplyMostly by the maxillary

nerve through its branches:Greater palatine nerveLesser palatine nerveNasopalatine nerve

Glossopharyngeal nerve supplies the region of the soft palate

Motor Nerve Supply

Blood SupplyBranches of the maxillary

arteryGreater palatineLesser palatineSphenopalatine

Ascending palatine, branch of the facial artery

Ascending pharyngeal, branch of the external carotid artery

Anatomy of The pharynx Site

Midline of the neckFrom skull base to esophagusIn front of upper 6 Cervical vertebra

Behind :The Nose

The MouthThe larynx

Seen from behind

Anatomy of The pharynx Shape

Irregular Fibromuscular tube lined by mucous membrane

Length: 15 cm

Anatomy of The pharynx Structure The wall is formed of 4 layers

1-Mucous membrane2- pharyngeal aponeurosis3-muscle layer4-Bucco-pharyngeal fascia

Stratified squamous epithelium except the nasopharynx, it is pseudo-stratified with goblet cells

Loose connective tissue which contains lymphoid tissue that aggregates in some areas forming tonsils (Waldayer’s ring)

Formed of 3 muscles, superior middle and inferior constrictor muscles

A thin coat of connective tissue

What is Waldeyer’s ring?The lymphoid tissue in thepharyngeal aponeurosisaggregates in some areasforming tonsils:1-one nasopharyngeal tonsil2- two palatine tonsils3- two lingual tonsils

Anatomy of the pharynxCompartments

NasopharynxOropharynxLaryngopharynx (Hypopharynx)

Seen from behind

NasopharynxOropharynxLaryngopharynx (Hypopharynx)

Seen from lateral

Nasopharynx -Behind the nasal cavity-Extends from skull Base superiorly to the soft palate inferiorly- Communicates inferiorly

with the oropharynx through the velo-pharyngeal sphincter

- The nasopharyngeal tonsil lies in the roof

- The pharyngeal opening of ET lies in the lateral wall

Oropharynx Behind the oral cavity (in front of 2nd&3rd

Cervical vertebra)

From the soft palate superiorly to tip of epiglottis inferiorly

Communicates: Anteriorly with the oral cavity Superiorly with the nasopharynx Inferiorly with the hypopharynx

The paatine tonsils lie laterallybetween the anterior and posteriorpilars

The anterior pillar formed by

palatoglossus muscle

The posterior pillar formed

By palatopharyngeus m

The tonsils lie between the Two pillars

Hypopharynx Behind the Larynx (in front of 3rd

to 6th Cervical vertebra)

From the tip of epiglottis superiorly to

the lower border of cricoid cartilageInferiorly

Communicates:- Anteriorly with the Larynx- Superiorly with the oropharynx- Inferiorly with the esophagus

The hypopharynx does not onlylie behind the larynx BUT also

Projects laterally on each side of the larynx

So it is formed of :- Postcricoid region ( behind

the larynx)- Two pyriform fossa (on each

side of the larynx

Seen from behind

Cross section

Blood supplyFrom the External Carotid Artery & its branches1- Tonsillar artery (from Facial Artery)2-Ascending palatine artery (from Facial Artery)3-Ascending pharyngeal Artery (from external carotid)4-Descending palatine artery ( from Maxillary artery.5-Dorsalis lingulae artery (from Lingual artery)

Lymph DrainageNasopharynx ---►Retropharyngeal ----►UDCLN

Oropharynx --- ► UDCLN

Hypopharynx --- ► UDCLN

Nerve SupplyMotor ---► X Except : Stylopharyngeus --►IXTensor palati -- ► V

Sensory --►- Nasopharynx: V- Oropharynx: IX- Laryngopharynx: X Autonomic:- sympathetic: SCG- Parasympathetic: through VII

Laryngeal CartilagesPaired

Arytenoid cartilageCorniculate cartilageCuneiform cartilage

Unpaired:Thyroid cartilageCricoid cartilageEpiglottis

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1. Hyoid bone

2. Thyroid cartilage

3. Cricoid cartilage

4. Tracheal cartilages

AAdddduuctctoorsrs

Thyroid Cartilage

Hyaline cartilageLargestEncloses the larynx

anteriorly and laterallyTwo alaeOssification

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Cricoid CartilageHyaline cartilageDirectly below the

thyroid cartilageStrongestShape: Signet ringLamina – flat portionOnly complete annular

support of the larynxArticulates w/ Inferior

cornu of the thyroid cartilage

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EpiglottisFibroelastic cartilageLeaf-shaped structurePetiole – small narrow

portion of the glottis

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Arytenoid CartilageMostly hyaline cartilageSmaller in sizeResponsible for opening and closing of the larynxShape: pyramidal

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Arytenoid CartilageAnterior

Vocal process - receives the attachement of the mobile end of each VC

LateralMuscular process

ArticulationCricoarytenoid joint

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Corniculate CartilagesFibroelasticCartilages of SantoriniSmall cartilages above the arytenoid and in the

aryepiglottic folds

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Cuneiform CartilagesFirboelastic cartilagesCartilages of WrisbergElongated pieces of small yellow elastic cartilage

in the aryepiglottic folds

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Triticeous Cartilage

Cartilago triticeaSmall elastic cartilage

in the lateral thyrohyoid ligament

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Laryngeal LigamentsExtrinsic

Thyrohyoid membrane and ligaments

Cricothyroid membrane and ligaments

Cricotracheal ligamentEpiglottis

IntrinsicElastic membraneQuadrangular

membraneConus elasticus

(cricovocal membrane)Median cricothyroid

ligamentVocal LigamentThyroepiglottic

ligament56

Extrinsic LigamentsThyrohyoid membrane

pierced on each side by: 1. Superior laryngeal vessels 2. Internal branch of superior

laryngeal nerveMedian thyrohyoid ligament – thickened median portionLateral thyrohyoid ligament – thickened posterior border - where cartilago triticea is often

found

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Extrinsic LigamentsCricothyroid membrane and ligaments

May be pierced for emergency tracheotomy (cricothyrotomy)

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Extrinsic LigamentsCricotracheal Ligament

Attaches the cricoid cartilage to the first attached ring

Epiglottis suspended in position by membranous connections to

the hyoid bone, thyroid cartilage and base of the tongue

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Intrinsic LigamentsElastic membrane

Divided into upper and lower parts by the ventricle of the larynx

Quadrangular membraneUpper part of the elastic membraneBoundaries

Epiglottis , arytenoid, corniculate cartilage, false cordForms part of wall between upper pyriform sinus and

laryngeal vestibule

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Intrinsic LigamentsConus elasticus (cricovocal membrane)

Lower part of elastic membraneComposed mainly of yellow elastic tissueBoundaries

Inferior: superior border of cricoid cartilage Superoanterior: deep surface of angle thyroid cartilage Superoposterior: vocal process of arytenoid cartilage

Median cricothyroid ligament – thickened anteior partVocal Ligament – free upper edge

Thyroepiglottic ligament

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Cavity of the Larynx

Divided into 3 parts:Vestibule VentricleSubglottic space

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Cavity of the Larynx

Vestibule – boundaries:Anterior: posterior surface of epiglottisPosterior: interval between arytenoid

cartilagesLateral: inner surface of aryepiglottic

folds and upper surfaces of the false cord

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Cavity of the Larynx

Glottis (rima glottidis) Abduction: Respiration,

wide and triangular Adduction: Phonation,

slit-like appearance

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• Ventricle• Saccule – conical pouch at anterior part

Cavity of the LarynxSubglottic spacePreepiglottic space

Boundaries:Anterior: thyrohyoid membraneAnteroasuperior: hyoidSuperior: valleculaPosterior: part of the epiglottisLateral: hyoepiglottic ligament

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Pre-Epiglottic SpaceBound sup by hyo-

epiglottic ligament, ant by thyrohyoid memb. & thyroid cartilage and posteriorly by epiglottis

Filled with fat and areolar tissue

Continuous with para-glottic space

Cx of laryngeal surface of epiglottis readily spread to PreEpiSpace

Reinke’s SpaceMucosa over the vocal

ligament loosely attached to ligaments

Thus there is a submucosal space along most of the length of truer VC

Para-glottic space

Cavity of the LarynxFalse Cords (ventricular bands)

Anteriorly: angle of the thyroid cartilagePosteriorly: bodies of the arytenoid cartilage

True cordsVoice productionProtection of lower respiratory tractAnteriorly,: angle of thyroid cartilagePosteriorly: vocal processes of the arytenoid

cartilagesEnclose vocal ligament and a major part of the vocalis

muscle 69

Laryngeal JointsCricothyroid Joint

Between inferior cornu of the thyroid cartilage and facet on the cricoid cartilage at the junction of the arch and lamina

Two movements:RotationGliding

Cricoarytenoid Jointbet. base of the

arytenoid cartilage and the facet on the upper border of the lamina of the cricoid cartilage

Two movements:RotationGliding

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Laryngeal MusclesIntrinsic Muscles

Interarytenoid muscle Transvers Oblique

Post. Cricoarytenoid m.Lateral cricoarytenoid

m.Thyroarytenoid m.Cricothyroid m.

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Extrinsic MusclesDepressor group

Elevator groupConstrictor musclesPharyngeal muscles

Intrinsic muscles

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Nerve SupplySupplied by Vagus nerve:

Superior laryngeal n. Internal branch (sensory) – areas above the glottis External branch (motor and sensory) Motor – Cricothyroid muscle

Sensory – Anterior infraglottic larynx at level of cricothyroid membrane

Inferior (recurrent) laryngeal n. Motor – all intrinsic laryngeal muscles of SAME side (except

cricothyroid) and interarytenoid muscle of BOTH sides Sensory – areas below the glottis

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Blood SupplyUpper Larynx

External carotid arterySuperior thyroid arterySuperior laryngeal

arteryLower Larynx

Subclavian arteryThyrocervical arteryInferior thyroid arteryInferior laryngeal artery

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Venouos DrainageUpper Larynx

Superior laryngeal veinSuperior thyroid veinInternal jugular vein

Lower LarynxInferior laryngeal veinInferior thyroid veinInnominate vein

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Lymphatic DrainageMain: Deep Cervical group L.N.

Supraglottic area98%: Pedicle Ant. End of aryepiglottic fold ->

pass laterally and leave the larynx through the thyrohyoid membrane ->Upper deep cervical nodes (bet. Digastric tendon and omohyoid muscle)

2%: Lower cervical chain or spinal accessory chain

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Lymphatic DrainageInfraglottic area – 3 pedicles

1. Anterior pedicle -> cricothyroid membrane -> prelaryngeal (Delphian) nodes ->deep inferior cervical nodes

2. 2 Posterolateral pedicles -> cricotracheal membrane -> paratracheal chain/others to inferior jugular chain

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THANKS