Dissection 11 - Pterygopalatine Fossa and Oral Cavity

Dissection Guide

Osteology

• Anterior and posterior nasal apertures (choanae) and nasal septum

  • Nasal aperturs = openings into nasal cavity

• Frontal, maxillary, sphenoid, ethmoidal sinus

  • Note that sphenoid sinus located posterior to ethmoid sinus

Nasal Cavity

• Openings = anterior nasal choanae and posterior nasal choanae

  • Posterior nasal choanae = start of nasopharynx

• ID superior, middle, and inferior turbinates

  • Sphenoethmoidal recess located superior to superior turbinate → Sphenoid sinus

• ID superior, middle, and inferior meatus

  • Semilunar hiatus seen in middle meatus when lift middle turbinate

    • Superior opening → Frontal sinus

    • Inferior opening = osteum of the maxillary sinus → Maxillary sinus

  • Inferior meatus contains opening of nasolacrimal duct

• Note that ethmoidal air cells from ethmoidal sinus flow into semilunar hiatus, middle meatus, and superior meatus

Maxillary Sinus

• Exposed by removing mucosa and bone on the lateral nasal wall over the middle and inferior turbinates

• Infraorbital n. runs through the roof of the maxillary sinus

  • Branches into superior alveolar n. → Provide SS to maxillary teeth

Soft Palate

• Elevates when swallowing to protect nasopharynx

• Uvula dangles in the middle

Nasopharynx

• Eustacian tube in the middle of torus tubarius

  • Anterior fold = salpingopalatine fold

    • Under lies salpingopalatine m.

  • Posterior fold = salpingopharyngeal fold

    • Under lies salpingopharyngeus m.

  • Tube opened when yawning or swallowing, allowing equalizing pressure

• Levator veli palatini located inferior to opening of auditory tube (innervated by CN X)

• Tensor veli palatini located right by the medial pterygoid plate (innervated bby CN V3)

  • Tendon slings around pterygoid hamulus (inferior portion of medial pterygoid plate

Pterygopalatine fossa

• Sphenopalatine a., blood to nasal cavity

• Palatine canal: vertically oriented at the base of the hard palate

  • Descending palatine a., greater and lesser palatine n. run through

  • A. deep to nerves

• PT ganglion located where the greater/lesser petrosal n. and n. of the pterygoid canal meet

  • Para to lacrimal gland and nasal/oral mucosa synapse here (CN VII)

• Pharyngeal tonsils, located on the roof of the nasopharynx

Oral cavity

• Oropharynx boundaries = Soft palate to tip of epiglottis

• Palatoglossal fold and palatopharyngeal folds may have the palatine tonsils beteween them

  • The folds cover the respective m.

• Expose submandibular gland, lingual n. and submandibular duct

  • Note that duct crosses superior to lingual n.

  • Lingual n. descends while submandibular duct ascends

• Hypoglossal n. found significantly inferiorly between mylohyoid (lateral) and hyoglosus (medial)

Tongue

• Median lingual sulcus = divides midline of tongue

• Sulcus terminalis = line formed by circumvallate papillae

  • Marks start of posterior 1/3 of tongue

• Foramen cecum = point made by circumvallate papillae

Bolded Terms

Anterior and posterior nasal aperture (choanae)

• Bony openings that mark the anterior and posterior boundaries of the nasal cavity

Auditory (Eustachian) tube

• Has an opening in the nasopharynx

• Connect nasopharynx to middle ear

• Can be used to equalize pressure

Descending palatine a.

• Branch of maxillary a.

• Passes in palatine canal deep to greater and lesser palatine n.

Foramen cecum

• Point on posterior aspect of tongue made by circumvallate papillae

Greater and lesser palatine n.

• Descends through the palatine a. and branches from CN V2

• Greater is larger than lesser

Hyoglossus m.

Hypoglossal n.

Infraorbital n.

• Runs along the roof of the maxillary sinus

• Gives off superior alveolar n. within the maxillary sinus

Levator veli palatini m.

• Soft palate m. located just inferior to opening of eustacian tube in nasopharynx

• Innervated by CN X

Lingual n.

Maxillary sinus

• Opens into the middle meatus via the osteum of the maxillary sinus

Medial pterygoid plate

• Part of sphenoid bone with a pterygoid hamulus at the inferior aspect

Median lingual sulcus

• Midline dividing L and R part of dorsal tongue

Nasal septum

• Divides L and right nasal cavity

Nasolacrimal duct

• Opens into inferior meatus

• Reason why crying → runny nose

N. of the pterygoid canal

• Runs posterior from the PT ganglion

• Made from the greater and deep petrosal n.

Oropharynx

• Boundaries = soft palate → tip of epiglottis

Osteum of maxillary sinus

• Inferior opening of the semilunar hiatus

Palatine canal

• Vertically running canal that terminates at the base of the hard palate

• Descending palatine a. + greater/lesser palatine n. run through

Palatine tonsil

• Located between palatoglossal and palatopharyngeal folds

Palatoglossal fold

• Mucus membrane covering the palatoglossus m.

Palatoglossus m.

• Deep to palatoglossal fold

Palatopharyngeal fold

• Mucus membrane covering the palatopharyngeus m.

Pharyngeal tonsils

• Located at the roof of the nasopharynx

Pterygoid hamulus

• Inferior portion of medial pterygoid plate

• Where tendon of tensor veli palatini hooks around

Pterygopalatine ganglion

• Located at the junction between the greater and lesser palatine n. and n. of the pterygoid canal

• Where para for nasal/oral mucosa and lacrimal gland synaose

Salpingopalatine fold

• Anterior fold of torus tubarius

Salpingopalatine m.

• Deep to salpingopalatine fold

Salpingopharyngeal fold

• Posterior border of torus tobarius

Salpingopharyngeus m.

• Deep to salpingopharyngeal fold

• Innervated by CN X

Semilunar hiatus

• Located within the middle meatus (anterior portion)

• Has 2 openings (into frontal and maxillary sinus)

Soft palate

• Posterior to hard palate

Sphenoethmoidal recess

• Located superior to superior turbinate

• Opening into sphenoid sinus

Sphenopalatine a.

• Branch of maxillary a.

• Vasculature in the nasal cavity

Submandibular duct

Submandibular gland

Sulcus terminalis

• Line on tongue formed by cicumvallate palillae

• Marks the posterior 1/3 of tongue

Superior alveolar n.

• Branch of CN V2

• SS to maxillary dentition

Superior, middle, and inferior meatus

• Located just below corresponding turbinates

Superior, middle, and inferior turbinates

• Curved bony structures that project from the lateral walls of the nasal cavity

Tensor veli palatini m.

• Innervated by CN V3

• Just deep to medial pterygoid plate

• Tendon hooks around pterygoid hamulus

Torus tubarius

• Mucous membrane + cartilage that surrounds the eustacian tube in the nasal cavity

Uvula

• Innervated by CN X