Oral Cavity, Oral Pharynx and Palatine Tonsil

Palpable structures in the vestibule of the oral cavity

The vestibule of the mouth is the space between the lips and the teeth. If you start in the mid line along the bottom, you can feel the inferior frenulum. Move your finger to the side until it moves up along a ridge, this is the anterior border of the ramus of the mandible. While your finger is on this border, bite down and you will feel the masseter muscle contracting. If you move your finger as far up as you can go, you will feel the coronoid process of the ramus and the tendinous insertion of the temporalis muscle. Now move your finger in the upper recess of the vestibule until you come to the mid line again and you will feel the upper frenulum. Look in your own mouth for the opening of the parotid duct that enters the vestibule opposite the 2nd upper molar tooth.

Oral Cavity Proper

Structures that you should be able to feel or see in your own mouth.

Figure 1.

First, the boundaries of the mouth are:

	superior--hard and soft palates
	inferior--tongue and floor of mouth
	anterolateral--upper and lower teeth
	posterior--palatoglossal fold (5)

Structures to identify:

vestibule
hard palate
soft palate
uvula
palatoglossal arch
palatine tonsil
palatopharyngeal arch
posterior wall of oropharynx
pterygoid hamulus

Figure 2. Tongue elevated.

frenulum of tongue
ridge formed by deep lingual vein
sublingual fold
sublingual caruncle
opening of submandibular duct

The sublingual gland forms the sublingual fold and sends multiple small ducts into the mouth along the fold.

Figure 1

Figure 2

Surface of the tongue viewed from above.
Note the tip of tongue, epiglottis and soft palate with the uvula as points of reference!

Identify:

anterior 2/3rd of tongue
posterior 1/3rd of tongue
palatogossal fold
palatine tonsil
fungiform papillae
circumvallate papillae
sulcus terminalis
foramen cecum
foliate papillae

Innervation:
Anterior 2/3rd:

	general sensation--lingual nerve (V3)
	taste--chorda tympani (VII)

Posterior 1/3rd:

	general sensation--glossopharyngeal (IX)
	taste--glossopharyngeal (IX)

Floor of the Mouth

Here is a perfect example of how important it is to orient yourself. In order to show the structures in the floor of the mouth, the tongue must be reflected posteriorly (notice the vertebral column). I always look for the mandible for anterior orientation.
In opening up the floor of the mouth, the mucous membrane is gently incised just above the sublingual gland and the fascia covering the gland (sg) is pulled posteriorly along with the tongue. This reveals:

	mylohyoid muscle (floor)
	geniohyoid muscle just above the mylohyoid

The mylohyoid muscles of the two sides joint in the mid line forming a sling across the floor of the mouth. In the section of the head and neck, the mylohyoid muscle can be seen in cross section.

Note where the tip of the tongue is
It has been displaced posteriorly.

Removal of the fascia around the sublingual gland (slg) and the deep part of the submandibular gland (sm) allows you to visualize the remainder of the structures of the mouth.

	styloglossus muscle (sg)
	hyoglossus muscle (hg)
	genioglossus muscle (gg)
	submandibular duct (5)
	lingual nerve (1)
	submandibular ganglion (2)
	hypoglossal nerve (3)
	C1 nerve to geniohyoid (4)

You can also see the genioglossus muscle from the sectioned tongue.

Muscle	Origin	Insertion	Action	Nerve Supply
styloglossus	styloid process	merges with hyoglossus and genioglossus muscles in the tongue	draws tongue up and back to aid swallowing food	XII
hyoglossus	greater horn of hyoid bone	merges with styloglossus and genioglossus muscles	draws side of tongue down	XII
genioglossus	genial tubercle of mandible	fans out in the tongue to make up the bulk of the tongue	pulls tongue forward, sticking the tongue out	XII
intrinsic muscles	tissues of tongue	tissues of tongue	produce small changes in the contour of the surface of tongue	XII
mylohyoid	mylohyoid line of mandible	hyoid bone and raphe	elevates hyoid bone and floor of mouth to aid in swallowing	nerve to mylohyoid (V3)
geniohyoid	lower genial tubercle of mandible	body of hyoid bone	elevate hyoid bone or depress mandible	C1

You will now identify the structures found in the lateral wall of the oropharynx. This is where the palatine tonsil is located. Again, orient yourself: identify the tongue, hard palate, hyoid bone and soft palate.
Identify the palatoglossal arch and the palatopharyngeal arch. Find the palatine tonsil between the two arches, if it is present. Beneath the mucosa of the arches, identify the small palatoglossus (pg) and palatopharyngeus (pp) muscles. You might also see the superior pharyngeal constrictor (SC) and middle pharyngeal constrictor (mc) at this stage.

When the tonsil is removed, you can see the structures that make up the tonsillar bed and that could be injured during a tonsilectomy.

	superior pharyngeal constrictor (SC)
	pterygomandibular raphe (PR)
	middle pharyngeal constrictor (MC)
	tonsillar branch of facial artery (1)
	glossopharyngeal nerve (2)
	stylohyoid ligament (3)

You might also be able to see the buccinator muscle (BUC) in this dissection. The pterygomandibular raphe serves as an insertion point for two muscles: superior constrictor and buccinator.

List of Items Covered in this Lesson

Bones

mandible

genial tubercles

mylohyoid line

maxilla

palatine process

palatine

horizontal process

hyoid

lesser horn

greater horn

medial pterygoid plate

pterygoid hamulus

Muscles

styloglossus

hyoglossus

genioglossus

mylohyoid

geniohyoid

palatoglossus

palatopharyngeus

Arteries

lingual

tonsilar branch of facial

Nerves

glossopharyngeal

hypoglossal

lingual

submandibular ganglion

C1 fibers

Tongue

sulcus terminalis

foramen cecum

fungiform papillae

foliate papillae

circumvallate papillae

frenulum

sublingual fold

anterior 2/3rd

posterior 1/3rd

sublingual caruncle

opening of submandibular duct

Tonsil region

palatoglossal fold

palatopharyngeal fold

palatine tonsil

superior pharyngeal constrictor

pterygomandibular raphe

stylohyoid ligament

glossopharyngeal nerve

tonsilar branch of facial artery

AFGALALY محمد عبد الفتاح جلال

Oral Cavity, Oral Pharynx and Palatine Tonsil

Oral Cavity Proper

Floor of the Mouth

List of Items Covered in this Lesson