Lab 6 Exam-Day Review

✍️ Wording

Use full names and anatomical directions. Spelling counts: palatine aponeurosis · pterygoid hamulus · oropharyngeal isthmus · epiglottic vallecula · salpingopharyngeus · stylopharyngeus · hypoglossal · mylohyoid · geniohyoid · incisive foramen.
Action verbs matter: tensor = tenses, levator = elevates. No palate muscle “thickens.”

★ High-yield traps

Pharyngotympanic tube = middle ear ↔ nasopharynx (not the inner ear, not the outside).
Soft palate muscles = CN X (pharyngeal plexus) except tensor veli palatini = CN V3. Tongue muscles = CN XII except palatoglossus = CN X.
Hyoglossus sandwich: CN XII superficial, lingual artery deep → the muscle is the landmark for finding the artery.
CN XII lesion → tongue points TOWARD the lesion. CN X lesion → uvula points AWAY.
Tonsillectomy: CN IX deep to the tonsillar bed (taste/sensation posterior ⅓ + ear pain). Rare but serious: internal carotid artery.
Geniohyoid = C1 riding with CN XII, not CN XII. Mylohyoid + anterior digastric = V3 (nerve to mylohyoid).
Molar roots (2nd/3rd) lie below the mylohyoid line → submandibular space → Ludwig’s angina.
Greater palatine foramen is in the palatine bone. Anterior hard palate = nasopalatine nerve via the incisive foramen.

2 · Oral Regions & Pharynx Subdivisions

Region	Boundaries / definition	Contents & high-yield
Oral vestibule	Horseshoe space between the lips/cheeks and the teeth/gums	Parotid duct opens here, opposite the maxillary 2nd molar
Oral cavity proper	Inside the teeth. Superior = hard palate; inferior = muscular floor (mylohyoid); posterior = palatoglossal arch / oropharyngeal isthmus	Submandibular + sublingual ducts open here
Oropharynx	Soft palate → superior border of the epiglottis	Tonsillar bed, epiglottic vallecula
Laryngopharynx	Epiglottis → cricoid → esophagus	Piriform recess; opens into the laryngeal inlet

Epiglottic vallecula

Pocket between the posterior ⅓ of the tongue (anterior) and the epiglottis (posterior); paired, split by the median glosso-epiglottic fold.
Oropharynx.
Intubation: laryngoscope blade sits here → lifts the tongue + epiglottis → exposes the laryngeal inlet.

Mallampati score

Size of the tongue relative to the oral cavity (how much oropharynx is visible).
High score → difficult intubation → plan a video laryngoscope.

Epiglottis

Elastic cartilage; seals the laryngeal inlet during swallowing (larynx rises, tongue base pushes it down).
Its superior border = oropharynx / laryngopharynx boundary.

Vallecula vs. piriform recess

Vallecula	Anterior to the epiglottis · oropharynx · laryngoscope blade
Piriform recess	Lateral to the laryngeal inlet · laryngopharynx · fish bones → internal laryngeal nerve

3 · Hard Palate

Bones (anterior → posterior)

Palatine process of maxilla→Horizontal plate of palatine bone

Same bony plate = floor of the nasal cavity. The palatine aponeurosis (tensor veli palatini tendon) attaches the soft palate to its posterior edge.

Adenoid cystic carcinoma

Minor salivary gland tumor of the posterior palate → perineural (retrograde) spread:

Greater palatine nerve→Palatine canal→Pterygopalatine ganglion→Pterygoid canal→Cranial cavity

Foramen	Bone / location	Nerve (CN V2)	Artery (maxillary artery, 3rd part)	Supplies
Incisive	Maxilla; midline behind the incisors	Nasopalatine	Septal branch of the sphenopalatine	Anterior hard palate
Greater palatine	Palatine bone; medial to the 3rd molar	Greater palatine	Greater palatine	Posterior hard palate + palatal gingiva
Lesser palatine	Palatine bone; just posterior to the greater	Lesser palatine	Lesser palatine	Soft palate

★ Palate sensation — front to back: N → G → L

Nasopalatine (incisive) → Greater palatine → Lesser palatine (soft palate) — all V2, passing through the pterygopalatine ganglion without synapsing. Posterior soft palate / fauces / tonsil area = CN IX (afferent limb of the gag reflex).

Greater palatine artery path

Maxillary artery (3rd part)→Descending palatine artery→Greater palatine canal / foramen→Runs anteriorly→Incisive canal: anastomoses with sphenopalatine artery

4 · Soft Palate Muscles

Muscle	Key feature	Action	Nerve
Tensor veli palatini	From the tube cartilage; tendon hooks around the pterygoid hamulus → palatine aponeurosis	Tenses the soft palate; opens the pharyngotympanic tube	CN V3 (1st arch)
Levator veli palatini	From the tube cartilage + petrous temporal; no pulley	Elevates the soft palate (seals the nasopharynx); opens the tube	CN X
Palatoglossus	Under the anterior pillar	Elevates the posterior tongue; pulls the palate down → closes the oropharyngeal isthmus	CN X
Palatopharyngeus	Under the posterior pillar	Elevates + shortens the pharynx; draws the posterior pillars together; pulls the palate down	CN X
Muscle of the uvula	Inside the uvula	Shortens/elevates the uvula	CN X

CN X lesion — uvula

Right CN X lesion → right levator paralyzed → healthy left levator pulls → uvula deviates to the left (away from the lesion).

Soft palate at a glance

Posterior ⅓ of the palate; ends as the uvula
Job: elevates → seals the nasopharynx (no nasal regurgitation; no nasal air escape in speech)
Sensation: lesser palatine nerve (V2) + CN IX posteriorly

5 · Tonsillar Pillars & Tonsillar Bed

	Anterior pillar	Posterior pillar
Fold	Palatoglossal fold	Palatopharyngeal fold
Muscle	Palatoglossus (CN X)	Palatopharyngeus (CN X)
Marks	Oral cavity → oropharynx (oropharyngeal isthmus)	Posterior border of the tonsillar bed

★ Tonsillectomy

Layers outward: palatine tonsil → tonsillar bed → superior pharyngeal constrictor → CN IX → internal carotid artery.

CN IX injury: temporary loss of taste + general sensation to the posterior ⅓ of the tongue and ear pain (referred otalgia — CN IX also supplies the middle ear).
Rare but serious: internal carotid artery. (Tonsillar branch of the facial artery = routine bleeding.)

6 · Nasopharynx Lateral Wall & Pharyngotympanic Tube

Anterior → posterior on the lateral wall. The salpingopharyngeal fold (salpingopharyngeus) runs inferiorly from the torus; the pharyngeal tonsil (adenoids) sits on the roof/posterior wall.

Muscles that open the tube

Tensor veli palatini — V3
Levator veli palatini — CN X
Salpingopharyngeus — CN X

Swallowing on a plane → tube opens → middle ear pressure equalizes.

Clinical

Adenoid hypertrophy blocks the tube opening → poor middle ear ventilation → effusion → otitis media. Children: tube shorter + more horizontal.
Nasopharyngeal tumor (pharyngeal recess) → tube blocked → unilateral effusion + conductive hearing loss in an adult.

Longitudinal pharyngeal muscle	Origin	Nerve	Special action
Stylopharyngeus	Styloid process	CN IX (only muscle; 3rd arch)	Elevates + widens the pharynx
Palatopharyngeus	Soft palate	CN X	Elevates + shortens
Salpingopharyngeus	Tube cartilage (salpingo- = tube)	CN X	Elevates; helps open the tube

“Style is 9, the rest are 10.” All three elevate the pharynx during swallowing.

7 · Tongue Muscles

Extrinsic muscle	From	Action	Nerve
Genioglossus	Superior mental spine (mandible)	Protrudes + depresses	CN XII
Hyoglossus	Hyoid (inferior)	Retrudes + depresses	CN XII
Styloglossus	Styloid (posterosuperior)	Retrudes + elevates	CN XII
Palatoglossus	Palatine aponeurosis	Elevates the posterior tongue	CN X ← exception

G = Go forward · H = Hold down & back · S = Sky & back · P = Palate nerve (CN X). Each muscle pulls the tongue toward its origin.

Intrinsic vs. extrinsic

Intrinsic	No bony attachment · change shape · CN XII
Extrinsic	Arise from bone/palate · move the tongue · CN XII (palatoglossus = X)

Genioglossus & the airway

Unconscious + supine → genioglossus relaxes → tongue falls posteriorly → blocks the oropharynx. Jaw thrust / chin lift pulls the mandible (its origin) forward → tongue follows.

Lesion	Structure	Points	Why
CN XII	Tongue (protruded)	Toward the lesion	Healthy genioglossus pushes it over
CN X	Uvula (“ahh”)	Away from the lesion	Healthy levator veli palatini pulls it over

“The tongue pushes, the uvula pulls.” Tongue deviates right → right CN XII lesion.

8 · Floor of the Mouth

Layers (oral side → skin)

Genioglossus↓Geniohyoid (C1 via CN XII)↓MYLOHYOID = the floor (V3)↓Anterior belly of digastric (V3)↓Platysma → skin

Ludwig’s angina

Rapidly spreading infection of the submandibular, sublingual and submental spaces
Source: 2nd/3rd mandibular molars — roots below the mylohyoid line
Pus pushes the tongue up and back → airway obstruction
Toothache, trouble speaking/swallowing, swollen tongue, firm swollen neck

Muscle	Attachments	Action	Nerve
Mylohyoid	Mylohyoid line → midline raphe + hyoid	Elevates the floor + hyoid (swallowing); depresses the mandible	Nerve to mylohyoid (V3, from the inferior alveolar nerve)
Geniohyoid	Inferior mental spine → hyoid body	Elevates + pulls the hyoid anteriorly; depresses the mandible	C1 via CN XII ← trap
Anterior belly of digastric	Mandible → intermediate tendon	Depresses the mandible	Nerve to mylohyoid (V3)
Posterior belly of digastric	Mastoid → intermediate tendon	Elevates the hyoid	CN VII

★ Mylohyoid line decides where a tooth abscess goes

Anterior teeth (roots above the line) → sublingual space. 2nd/3rd molars (roots below) → submandibular space → Ludwig’s angina.
V3 motor outside mastication: “My Ant Tensed” — Mylohyoid, Anterior digastric, Tensor veli palatini (+ tensor tympani).

9 · Hyoglossus Region — Telling Structures Apart

★ Hyoglossus sandwich

CN XII (+ lingual nerve + submandibular duct) lateral · lingual artery medial (deep). Find the hyoglossus, retract it, and the artery is underneath → ligated for base-of-tongue cancer resection or used for microvascular reconstruction. Lingual artery = 3rd branch of the external carotid (SALFOPMS); may share a linguofacial trunk with the facial artery.

Feature	Lingual nerve (V3)	CN XII	Lingual artery
Relation to hyoglossus	On it, superior	On it, inferior (just above the hyoid)	Deep to it
Duct	Loops under it (lateral → inferior → medial)	Below it, no loop	—
Hanging from it	Submandibular ganglion	Nothing (vena comitans alongside)	—
Traced posteriorly	Up into the infratemporal fossa (chorda tympani joins)	Crosses superficial to the internal + external carotid arteries	Arises from the external carotid near the greater horn of the hyoid
Look	Solid, white	Solid, white/cream, straight	Hollow (lumen), darker, tortuous
Function	Sensory anterior ⅔ + chorda fibers	Motor to tongue	Main tongue blood supply

10 · Salivary Glands & Parasympathetic Ganglia

Gland	Location	Duct & opening	Parasympathetic
Parotid	Anterior to the ear, superficial to the masseter	Crosses the masseter (V3) → pierces the buccinator (CN VII buccal) → vestibule opposite the upper 2nd molar	CN IX → otic ganglion
Submandibular	Hooks around the posterior border of the mylohyoid (large superficial + small deep part)	One duct → medially beside the frenulum (sublingual papilla)	Chorda tympani → submandibular ganglion
Sublingual	Entirely above the mylohyoid, under the floor-of-mouth mucosa; raises the sublingual fold; smallest	Many small ducts → lateral to the frenulum	Chorda tympani → submandibular ganglion

Submandibular ganglion (parasympathetic)

CN VII→Chorda tympani→Lingual nerve (V3)→Submandibular ganglion (synapse)→Submandibular + sublingual glands

“Chorda → Chomp → Chin glands.”

Pterygopalatine ganglion (parasympathetic)

CN VII→Greater petrosal nerve→Pterygopalatine ganglion (synapse)→Lacrimal + nasal, palatal, sinus, nasopharyngeal glands

In the pterygopalatine fossa, hanging below V2. V2 sensory fibers (greater/lesser palatine, nasopalatine) pass through without synapsing.

Lesion	Lost	Spared
Greater petrosal nerve	Dry eye; dry nose/palate; taste from the soft palate	Face, hearing, tongue taste, saliva
Chorda tympani	Taste anterior ⅔ of tongue; ↓ submandibular + sublingual saliva	Face, tears, hearing
Stylomastoid foramen	Facial muscles only	Tears, hearing, taste, saliva

“Tears, Ears, Taste, Face” = CN VII branches in the order they leave (greater petrosal → nerve to stapedius → chorda tympani → motor branches). A single-branch lesion loses only that branch.

Sialolithiasis → sialadenitis

Stone blocks the duct (usually submandibular: thicker, calcium-rich saliva; long duct running uphill)
Mucopurulent drainage, facial pain + swelling, foul taste
Antibiotics, hydration, sialogogues, sour candy/drinks
Stone removal risks the lingual nerve (loops under the duct)

11 · Mandible, Inferior Alveolar & Lingual Nerves

Inferior alveolar nerve block

Anesthetic at the mandibular foramen (medial ramus). The lingual nerve lies just anterior/medial in the same space → also numbed → anterior ⅔ of the tongue goes numb too.

Upper teeth = posterior, middle and anterior superior alveolar nerves (V2) → anesthetic must diffuse to several nerves.

Lingual nerve injury (3rd molar extraction)

Lies in soft tissue only against the lingual side of the 3rd molar (the inferior alveolar nerve is protected in the mandibular canal).

Loss of general sensation, anterior ⅔ of the tongue
Loss of taste (chorda tympani)
↓ salivation (submandibular + sublingual)

Lymph drainage of the tongue & lips

Anterior ⅓ tongue · medial lower lip	Submental nodes → deep cervical
Lateral tongue	Submandibular + jugulodigastric nodes
Upper lip · lateral lower lip	Submandibular nodes → deep cervical
Posterior ⅓ tongue	Deep cervical nodes directly (can spread down the internal jugular vein)

Lab 6 Exam-Day Review — Palate & Oral Cavity

1 · Exam-Day Rules & Top Traps