Session 9/ Checklist: Nasal cavity and paranasal sinuses

Nasal cavity and paranasal sinuses
Curricular Objectives
By the end of this session students are expected to:
Theory
1. Recall the main functions of nose and acknowledge its importance in clinical practice
2. Review the prominent features and dermatomes of the external nose
3. Outline the extent, divisions, and boundaries of the nasal cavity
4. Describe the boundaries of posterior nasal aperture
5. List and describe the main features of the lateral wall of the nasal cavity
6. Summarize the function of the different epithelia lining the nasal cavity
7. Discuss the blood supply of the nasal cavity
8. Define Kiesselbach’s plexus and list the arteries forming it
9. Acknowledge the importance of the submucosal venous plexus
10. Underline the types of innervations of the nasal cavity
11. Review the course of the nerve supplying the olfactory mucosa
12. List the spaces communicating with the nasal cavity and their opening sites
13. Describe function, drainage, and nerve supply of paranasal sinuses.
14. Relate the sensory nerve supply of paranasal sinuses to possible sites of pain
15. Uncover the relation between frontal and maxillary sinuses regarding their drainage
16. Appraise the fact that drainage orifice of the maxillary sinus lie near its roof
Practical
1. Review the parts of the external nose
2. Label the dermatomes of the external nose
3. Identify and Feel the cartilaginous and bony parts of the nose
4. Locate the nasal cavity and define its extents and main divisions
5. Mark the boundaries of the nasal cavity
6. Identify prominent features of lateral wall of nasal cavity
7. Name and locate the different types of epithelial tissue lining the nasal cavity
8. Recognize Little’s area and acknowledge its clinical importance
9. Trace the sphenopalatine artery and recall its origin and importance
10. Name & Locate the paranasal sinuses & their openings into lateral wall of nasal cavity
11. Mark the site of frontal and maxillary sinuses on the face (surface anatomy)
12. Label the paranasal air sinuses in skull X-ray
13. Palpate the frontal and maxillary air sinuses
14. Distinguish the nerves supplying the frontal and maxillary air sinuses
15. Follow the olfactory nerves to the bulb

Selected references and suggested resources
? Clinical Anatomy by Regions, Richard S. Snell, 9th edition
? Grant s Atlas of Anatomy, 13th Edition
? McMinn s Clinical Atlas of Human Anatomy, 7th Edition
? Anatomy for Babylon medical students (facebook page)
? Human Anatomy Education (facebook page)
? Human anatomy education (you tube channel)

Feedback and suggestions
? http://goo.gl/forms/SjyjGeUpvH
Session check list
? Clinical highlights:
? Main functions of the nose and nasal cavity are respiration and olfaction
? Diseases like rhinitis, sinusitis, nasal septal deviation and epistaxis are very common. It is essential for junior doctors to have a detailed knowledge of the anatomy of the region

? Suggested videos
? https://youtu.be/wJEenATGwg8
? https://youtu.be/PDOCXazJcxc

? Key landmarks:
? External nose/Nasal bones
? Nasal septum
? Conchae
? choana

? External Nose
? Fractures of nasal bones are common facial fractures from direct trauma to nose

? Extent & Divisions of the Nasal Cavity
? From the two nostrils anteriorly to the two Choanae posteriorly
? The inside of the nasal cavity is divided by a nasal septum into right and left halves
? The nasal septum (medial wall) rarely lies in the midline

? Boundaries of the nasal cavity
? Medial wall (nasal septum)
? Floor (hard palate)
? Separates the nose from the oral cavity
? Transmit nerves and vessels between the nasal and oral cavities
? Roof (cripriform plate of ethmoid + ……)
? Separates the nose from the cranial cavity
? Can be divided into anterior, middle and posterior thirds
? It is the narrowest wall of the cavity
? Lateral Wall
? This wall is complicated and formed by many bones
? Three bony projections called conchae with a space below each concha called meatus
? Sphenoethmoidal Recess is a small area located above the superior concha

? Linings of the cavity
? Three types of epithelia line the nasal cavity

? Blood supply of the nasal cavity
? Rich blood supply by branches of Ophthalmic, Maxillary, and Facial arteries
? Little’s area:
? Branches of the three main arteries anastomosis with each other forming a vascular plexus called Kiesselbach’s plexus
? Common site of epistaxis (nose bleeding)
? Submucous venous plexus
? A plexus of veins in the respiratory region, warm up the inspired air

? Nerve Supply of the Nasal Cavity
? Autonomic
? Sympathetic fibers: vasoconstriction of blood vessels
? Parasympathetic fibers: control nasal secretion
? Sensory (general)
? For pain, touch, &, temperature from the vestibule and respiratory region of nasal cavity
? Sensory (olfaction)
? For sense of smell from the olfactory region of the nasal cavity

? The Paranasal Sinuses and their Openings into the nasal cavity
? Four paranasal sinuses (air-containing cavities) within four bones around the nasal cavity
? Sphenoid/ Posterior, Middle, Anterior ethmoid/ Frontal/ Maxillary air sinus
? All lined by mucous membrane and drain their secretion into nasal cavity

? Nerve supply of the paranasal sinuses
? Understanding the nerve supply of the paranasal sinuses is important to understand the sites of pain in case of sinus infection
? Frontal: ophthalmic division of trigeminal nerve
? Maxillary: maxillary division of trigeminal nerve
? Ethmoidal/ Sphenoidal
Lab Activity List:
For each task below, identify the listed structures then answer the related questions

? Task 1 (External Nose):
? Tip/ Bridge/ Dorsum/ Ala of the nose
? Nostrils
? Nasal septum
? What makes the skeleton of the external nose?
? The nose communicates with exterior through ______________________
? Task 2 (Parts of nasal cavity):
? Vestibule
? Nasal cavity proper
? The nasal cavity communicates posteriorly with the nasopharynx through _________________
? Task 3 (nasal septum):
? Vertical plate of ethmoid
? Vomer
? Septal cartilage
? Which part of the nasal septum is mobile?
? Task 4 (Floor of Nasal cavity):
? Hard palate: maxilla/ palatine bone
? Incisive foramen and canal
? Greater and lesser palatine foramena
Hint: look at the inferior view of skull to see these foramena
? What are the structures passing through the above foramina?

? Task 5 (Roof of Nasal cavity):
? Nasal bones
? Cribriform plate of the ethmoid
? Body of the sphenoid
? The middle third of the roof separates the nasal cavity from which part of cranial cavity?
? Task 6 (Lateral Wall of Nasal cavity):
? Vestibule and conchae
? Superior/ middle/ inferior conchae and meati
? Spheno-ethmoidal Recess
? Which one of these conchae is independent and to which bone the other two belong?
? Name the largest and smallest concha
? Task 7 (Choanae)
? What are the bony structures forming the boundaries of Choanae?
? Task 8 (linings of Nasal cavity):
? Skin (vestibule)
? Respiratory mucosa
? Olfactory mucosa
? Draw a simple diagram of the lateral nasal wall showing the three epithelia lining the cavity
? What are the vibrissae and where they are found?
? Task 9 (Blood supply of Nasal cavity)
? Little’s area
? Name the main vessels anastomosing at this area
? Task 10 (Nerve Supply of the Nasal Cavity)
? Olfactory nerves / Olfactory bulbs
? Branches from V1 and V2
? List the structures involved in olfaction (in sequence) from the olfactory mucosa to the brain
? Task 11 (Paranasal Sinuses and their Openings into the nasal cavity)
? Sphenoid air sinus
? Ethmoid air sinus
? Frontal air sinus
? Maxillary air sinus
? Sphenoid air sinus opens into ________________________
? Posterior ethmoid sinuses open into _____________________
? Middle ethmoidal air sinuses open into ___________________ on the upper border of ________________
? Frontal & anterior ethmoidal sinuses drain through a channel called ________ into _______________
? Maxillary sinus opens into ________________________
? The nasolacrimal duct transmits _______________ from ________________ to open into _________________
? Name and locate the cavities related to maxillary sinus
? Compare the path of drainage of maxillary and frontal sinuses





Review questions:
1. List two places in the head where the external and internal carotid arteries anastomose.
2. The dorsum & the tip of the nose are supplied by ___________________________ division of CNV
3. What are the mechanisms responsible for draining the mucous of the paranasal sinuses?
4. Infection of the ethmoid sinuses can easily spread to the orbit. Explain why?
5. Pain in patients with frontal sinusitis may be referred to _____________________ area
6. Pain in patients with maxillary sinusitis may be referred to ___________________ Area and _____________

Homework
? The statement (The nasal septum usually lies in the midline) is INCORRECT.
A. Correct it
B. In your opinion, what can be the consequences if the septum is severely deviated?

? A 12-year-old boy admitted to casualty suffering a unilateral nose bleed. Examination revealed bleeding spot on the nasal septum.
A. Which area is the most likely source of bleeding?
B. What are the arteries supplying this location?
C. Which one of the arteries is most likely to be responsible?

? What happens when an opening of a paranasal sinus into the nose is closed? Think of common illnesses that may close these openings

? The location of the opening of the maxillary sinus exposes the sinus to infection and pus collection. Discuss

? You were asked to palpate the frontal and maxillary sinuses. Where will you press to assess for sinus tenderness