Biology 122 Spring, 2008

Laboratory 22

Nasal cavity, Paranasal sinuses and Hard palate

OBJECTIVES

At the end of this laboratory you should know:

1. The anatomical landmarks, bones and soft structures associated with the nasal cavity and nasopharynx.

a. For the nasal cavity the landmarks include the nares, nasal septum, vestibule, limen nasi, the conchae and meati, ethmoid bulla, agger nasi, olfactory sulcus, sphenoethmoidal recess, semilunar hiatus.

b. The bones associated with the nose are the nasal, maxillary, frontal, ethmoid, palatine, sphenoid, inferior nasal concha and vomer.

c. Neurovascular openings into the nasal cavity include the sphenopalatine foramen, incisive canal and the foramina of the cribriform plate for the olfactory nerves and anterior ethmoid artery.

d. Landmarks of nasopharynx are the choanae, soft palate, pharyngeal recess, pharyngeal tonsils, torus tubarius and ostium of the auditory tube.

2. The arrangement of the muscles of the soft palate and their innervation via motor branches of V and X.

3. The origin and distribution of the arteries of the nasal cavity.

4. The sensory innervation of the nasal cavity, including branches of the ophthalmic nerve (anterior ethmoid), the maxillary nerve and the olfactory nerves.

5. The names, locations and routes of drainage of the paranasal sinuses. Special attention should be given to the position of the ostia of the sinuses and the nasolacrimal duct relative to the meati.

6. The basic structure of the external nose, including the nasal bones and cartilaginous skeleton, and blood supply (especially via the anterior ethmoid artery).

PRELAB PREPARATION

1. Study the origin, course and distribution of nerve fibers leading to and exiting from the pterygopalatine fossa.

a) nerve of the pterygoid canal

b) greater and lesser palatine nerves

c) infraorbital nerve

d) nasopalatine nerve

e) pharyngeal nerves

2. Read the parts of Moore and Dalley on CN I, V₂ and V₃ and on the nasal cavity and paranasal sinuses (pp 1013-1022). Study descriptions and illustrations of the blood supply of the nasal cavity. The distribution of blood vessels and nerves within the cavity is difficult to trace in the cadaver and should be learned from textbook diagrams and descriptions.