Anatomy of the Head and Neck

lecture 15

Abbas A. A. Shawka

Medical student

2nd stage

Subjects

Oral cavity

Introduction • The oral cavity is inferior to the nasal

cavities

• opens onto the face through the oral fissure, and is continuous with the cavity of the pharynx at the oropharyngeal isthmus.

• The roof of the oral cavity consists of the hard and soft palates.

•

• The floor is formed mainly of soft tissues, which include a muscular diaphragm and the tongue.

• The lateral walls (cheeks) are muscular and merge anteriorly with the lips surrounding the oral fissure (the anterior opening of the oral cavity).

introduction• The posterior aperture of the oral

cavity is the oropharyngeal isthmus, which opens into the oropharynx.

• The oral cavity is separated into two regions by the upper and lower dental arches consisting of the teeth and alveolar bone that supports them

1. The outer oral vestibule :- between the dental arches and the deep surfaces of the cheeks and lips-the oral fissure opens into it and can be opened and closed by muscles of facial expression, and by movements of the lower jaw.

2. The inner oral cavity proper is enclosed by the dental arches .

Introduction • The oropharyngeal isthmus at the

back of the oral cavity proper can be opened and closed by surrounding soft tissues, which include the soft palate and tongue.

• Functions :-1. Inlet of digestive tract

2. Speech

3. Can be used for brathing

Oral cavity innervation

Maxillary

Maxillary

Maxillary

Floor of oral cavity

• 1. myelohyoid muscle ( nerve to myelohyoid – lingual n. – posterior trunk of mandibular nerve V3 )

• 2. geniohyoid muscle ( C1 fibers comes with XII )

Oropharyngeal triangle • free posterior border of the

mylohyoid muscle on each side forms one of the three margins of a large triangular aperture (oropharyngeal triangle) , which is a major route b y which structures i n the upper neck and infratemporal fossa of the head pass to and from structures in the floor of the oral cavity

• superior and middle constrictor muscles of the pharynx complete the margins of this triangle.

• Most structures that pass through the aperture are associated with the tongue and include

• muscles (hyoglossus,

• styloglossus) ,

• vessels (lingual artery and vein)

• nerves

• (lingual, hypoglossal [XII] , glossopharyngeal [IX] )

• lymphatics.

• Submandibular gland.

Tongue • forms part of the floor of the oral

cavity and part of the anterior wall of the oropharynx.

1. Apex of the tongue

2. Root of the tongue

3. Terminal sulcus of the tongue

4. Foramina cecum of the

tongue

Papillae • On the superior surface of oral part of

tongue

• Filiform papillae

• Fungiform papillae

• Vallate papillae

• Foliate papillae

• The papillae in general increase the area of contact between the surface of the tongue and the contents of the oral cavity.

• All except the filiform papillae have taste buds

• on their surfaces.

Tongue

• Pharyngeal surface of tongue

• NO papillae

• There is Lingual tonsils

• Inferior surface of tongue :

• Frenulum of the tongue

• Fimbriated fold

•

Tongue muscle • Intrensic muscle :-

1. lengthening and shortening it,

2. curling and uncurling its apex and edges, and

3. flattening and rounding its surface

Tongue muscle • Working in pairs or one side at a time the intrinsic muscles of

the tongue contribute to precision movements of the tongue required for speech, eating, and swallowing.

Tongue muscle • The genioglossus muscles:

1. depress the central part of the tongue, and

2. protrude the anterior part of the tongue out of the oral fissure (i.e. , stick the tongue out) ( a method to examine XII nerve function !!! )

• Hyoglossu muscle depress the tongue

but it is an important landmark in

the floor of oral cavity ?!

• The hyoglossus muscle is an important landmark in the floor of the oral cavity:

1. The lingual artery from the external carotid artery in the neck enters the tongue deep to the hyoglossus, between the hyoglossus and genioglossus .

2. The hypoglossal nerve [XII] and lingual nerve (branch of the mandibular nerve [V 3]), from the neck and infratemporal fossa of the head, respectively, enter the tongue on the external surface of the hyoglossus.

• The styloglossus muscles :-

• retract the tongue and pull the back of the tongue superiorly.

• Palatoglossus :-

• elevate the back of the tongue,

• move the palatoglossal arches of mucosa toward the

• midline, and

• depress the soft palate.

• MUSCLE OF SOFT PALATE AND TONGUE !!

Vessels • Lingual artery :-

• Origion from ECA

• pass deep to the hyoglossus muscle, and accompanies the muscle through the aperture (oropharyngeal triangle) formed by the margins of the mylohyoid, superior constrictor, and middle constrictor muscles, and enters the floor of the oral cavity.

• The lingual artery then travels forward in the plane between the hyoglossus and genioglossus muscles to the apex of the tongue.

• In addition to the tongue, the lingual artery supplies the sublingual gland, gingiva, and oral mucosa in the floor of the oral cavity.

• deep lingual veins :- (1)

• Accompany the artery in anterior portion of tongue ..

• Separate from the artery posteriorly by hyoglossus muscle.

• Accompany XII nerve on the external surface of Hyoglossus

• Exit through the triangular opening to join the IJV.

• The dorsal lingual vein :- (2)

• follows the lingual artery between the hyoglossus and genioglossus muscles and, like the deep lingual vein, drains into the internal j ugularvein in the neck.

1

2

Lymphatic Drainage • The pharyngeal part of the tongue

drains through the pharyngeal wall directly into mainly the jugulodigastricnode of the deep cervical chain.

• The oral part of the tongue drains both directly into the deep cervical nodes, and indirectly into these nodes by passing first through the mylohyoid muscle and into submental and submandibular nodes.

• The submental nodes are inferior to the mylohyoid muscles and between the digastric muscles.

• The submandibular nodes are below the floor of the oral cavity along the inner aspect of the inferior margins of the mandible.

?

?

• The tip of the tongue drains through the mylohyoid muscle into the submental nodes and then into mainly the jugula-omohyoid node of the deep cervical chain.

Innervation • Motor innervation :-

• All muscles of the tongue are innervated by the hypoglossal nerve [XII] except for the palatoglossusmuscle, which is innervated by the vagus nerve [X] .

• Sensory innervation :-

1. V

2. IX

3. X

• MENTIONED IN THE BEGINNING OF THE LECTURE …

Innervation • Parasymapthetic innervation :-

• TO BE OBSERVED IN NEUROANATOMY LECTURES …

Hard palate

• 1- anterior 3/4 of the hard palate is formed by maxilla bones.

• 2- posterior ¼ is formed by horizontal plates of palatine bones.

1

2

Soft palate

• acts as a valve that can be:

1. depressed to help close the oropharyngeal isthmus, and

2. elevated to separate the nasopharynx from the oropharynx.

• The soft palate is formed and moved by four muscles and is covered by mucosa that is continuous with the mucosa lining the pharynx and oral and nasal cavities.

Soft palate

• Muscles of soft palate

• 1- descends from the base of the skull( tnsor veli palatini , levator velipalatine )

• 2- ascend from the tongue and pharynx ( palatoglossus / palatopharyngeus )

• 3- one associated with uvula ( musculus uvulae )

?

Tensor veli palatine (TP)• Originate from the base of skull ..

• Attached to :-

• Scaphoid fossa ( root of pt processes )

• Pharyngotympanic tube

• Spine of sphenoid bone

• Lateral surface of medial pterygoid plate

• Pterygoid Hamulus

• Will form palatine aponeurosis which its margins are :-

• Hard palate ( palatine bone )

• Other side

• Free

Palatine aponeurosis

Tensor veli palatine (TP)

• The tensor veli palatini:

1. tenses (makes firm) the soft palate so that the other muscles attached to the palate can work more effectively.

2. opens the pharyngotympanic tubewhen the palate moves during yawning and swallowing as a result of its attachment superiorly to the membranous part of the pharyngotympanic tube.

Palatine aponeurosis

Levator veli palatine (LP)• Originate from the base of skull.

• Attached to :-

1. Area anterior to carotid canal ( petrous part of temporal bone )

2. Pharyngotympanic tube

• Insert into the palatine aponeurosis.

• do not pass around the pterygoid hamulus, but course directly from the base of the skull to the upper surface of the palatine aponeurosis . Therefore, they are the only muscles that can elevate the palate above the neutral position and close the pharyngeal isthmus between the nasopharynx and oropharynx.

• asking a patient to say " ah. If one side is not functioning, the palate deviates away from the abnormal side.

LP

Palatopharyngeus• Most fibers separated from TP by LP .

• Some fibers anteriorly attached to TP and to hard palate.

• The two palatopharyngeus muscles, one on each side, underlie the palatopharyngeal arches on the oropharyngeal wall. The palatopharyngeal arches lie posterior and medial to the palatoglossal arches when viewed anteriorly through the oral cavity.

aponeurosis

Palatopharyngeus• On each side, the palatine tonsil is

between the palatopharyngeal and palatoglossal arches on the lateral oropharyngeal wall.

• Functions :-

1. depress the palate and move the palatopharyngeal arches toward the midline like curtains-both these actions help close the oropharyngeal isthmus.

2. elevate the pharynx during swallowing.

aponeurosis

Palatoglossus• The palatoglossus muscle attaches to

the inferior (oral) surface of the palatine aponeurosis and passes inferiorly and anteriorly into the lateral surface of the tongue.

• Palatoglossal arches, one on each side, are lateral and anterior to the palatopharyngeal arches and define the lateral margins of the oropharyngeal isthmus

• Functions :-

• The palatoglossus muscles depress the palate, move the palatoglossal arches toward the midline like curtains, and elevate the back of the tongue. These actions help close the oropharyngeal isthmus.

Palatoglossus• The palatoglossus muscle attaches to

the inferior (oral) surface of the palatine aponeurosis and passes inferiorly and anteriorly into the lateral surface of the tongue.

• Palatoglossal arches, one on each side, are lateral and anterior to the palatopharyngeal arches and define the lateral margins of the oropharyngeal isthmus

• Functions :-

• The palatoglossus muscles depress the palate, move the palatoglossal arches toward the midline like curtains, and elevate the back of the tongue. These actions help close the oropharyngeal isthmus.

Vessels :-• Arteries :-

1. Greater palatine branch of maxillary a.

2. Ascending palatine branch of fascial a.

3. Palatine branch of ascending pharyngeal a.

• Veins

1. To pterygoid plexus

2. To pharyngeal plexus ( through palatine tonsils veins )

3. Directly to fascial v.

• Lymphatics

• Directy to deep cervical LN.

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1

Innervation to palate

Teeth blood supply • Inferior alveolar a. ( branch of

maxillary artery in ITF ) and will give incisor and mental branches ..

• Posterior superior alveolar a. ( branch of maxillary a. in pt fossa )

• Anterior superior alveolar a. ( branch of intraorbital a. which is a branch of maxillary a. in pt fossa )

gingiv blood supply

• lower gingiva

• Buccal – lingual a.

• Vestibular – inferior alveolar a.

• Upper gingiva

• Buccal – anterior and posterior superior alveolar a.

• Vestibular – nasopalatine and greater palatine arteries ( from nose )

Venous drainage of teeth • Inferior alveolar veins from the lower

teeth, and superior alveolar veins from the upper teeth drain mainly into the pterygoid plexus of veins in the infratemporal fossa, although some drainage from the anterior teeth may be via tributaries of the facial vein.

• The pterygoid plexus drains mainly into the maxillary vein and ultimately into the retromandibular vein and jugular system of veins.

• In addition, small communicating vessels pass superiorly, from the plexus, and pass through small emissary foramina in the base of the skull to connect with the cavernous sinus in the cranial cavity. Infection originating in the teeth can track into the cranial cavity through these small emissary veins.

Innervation of teeth

Innervation of gingiva

Innervation of gingiva