upper resp tract ~ hard

• Respiratory system anatomy covered.
• Includes anatomy of the respiratory tract.

Learning Outcomes

• Overview of the introduction and functions, structure, and innervation of the respiratory tract, focusing on the nose, pharynx, larynx, and trachea.

Upper Respiratory Tract Parts

• Consists of the nasal conchae (superior, middle, inferior), frontal sinus, sphenoidal sinus, nasopharynx, oropharynx, laryngopharynx, tongue, trachea, and esophagus.

Nose Parts

• External Nose:
• It is pyramidal in shape and consists of the apex (tip), root, and dorsum.
• Nostrils(Nares): A pair of piriform apertures.
• Medially, it features a nasal septum, and laterally, the ala of the nose.
• Nasal cavity

Blood Supply and Innervation

• Arterial Supply:
• The dorsal nasal branch (ophthalmic), infraorbital (maxillary), and alar and septal branches (facial) supply blood.
• Innervation Includes:
• Sensory innervation from the external nasal and infratrochlear (ophthalmic) nerves as well as the infraorbital (maxillary) nerve.
• Motor innervation from facial nerve branches.

Nasal Cavity

• Divided into two asymmetrical halves by the median nasal septum.
• Extends from the nostrils to the choanae.
• Includes the vestibule, which is close to the nostrils.
• It is lined by skin containing hairs and sebaceous glands.

Nasal Cavity Subdivisions

• Divided into two halves.
• Each half has walls (roof, floor, medial, and lateral).
• Each half measures approximately 5cm in height and 5-7cm in length.
• It is 1.5cm wide near the floor and 1-2mm near the roof.

Nasal Cavity Roof

• Formed by the cribriform plate of the ethmoid bone.
• Measures 7cm long and 2mm wide.
• Anterior slope consists of the nasal part of the frontal bone, nasal bone, & nasal cartilages.
• Posterior slope consists of the inferior surface of the body of the sphenoid.
• Middle horizontal part -cribriform plate of ethmoid.
• Slopes downwards both in front and behind.

Floor of Nasal Cavity

• Floor measures 5 cm long and 1.5 cm wide.
• Formed by the palatine process of the maxilla and the horizontal plate of the palatine bone.
• Shaped concavely from side to side.

Nasal Septum

• It is the median osseocartilaginous partition between the two halves of the nasal cavity.
• It is covered by mucous membrane on each side. It forms both the medial wall of the nasal cavities.
• Formation includes a bony part and cartilaginous parts.

Nasal Septum - Bony Formation

• Bony Formation:
• Perpendicular plate of the ethmoid bone.
• Vomer.

Nasal Septum - Cartilaginous Formation

• Septal cartilage
• Inferior nasal cartilage.

Nasal Septum - Cuticular Formation

• Fibro-fatty tissue and skin
• Columella.
• Vomero-nasal organ of Jacobson.

Nasal Septum - Arterial Supply

• Arterial supply

Nasal Septum - Venous Drainage

• Venous Drainage:
• Anteriorly, the superior ophthalmic vein.
• Posteriorly, the pterygoid venous plexus.
• Mobile part via the facial vein to the IJV (internal jugular vein)

Nerve Supply

• Includes the olfactory zone
• Also the anterior ethmoidal nerve (ophthalmic).
• The long Sphenopalatine Nerve and Short Sphenopalatine nerves & Greater palatine Nerve.
• Maxillary N, Pterygo palatine ganglion

Lateral Wall Subdivisions

• A small depressed area in the anterior part is called the vestibule.
• Vestibule lined by modified skin containing short, stiff, curved hairs called Vibrissae and contain sweat and sebaceous gland.
• The middle part is known as the atrium of middle meatus.
• Posterior part contains the concha.
• Spaces separating the concha are called meatuses.

Lateral Wall of Nose Parts

• Concha
• Agger nasi (mucous ridge)
• The atrium of the middle meatus
• Limen nasi (mucocutaneous ridge)
• Vestibule

Conchae and Meatuses

Nasal Conchae (Turbinate Bones)

• Inferior Concha:
• Separate bone extending horizontally backwards.
• Ends 1.25cm in front of the pharyngeal opening of the auditory tube and is continuous with the vestibule anteriorly.
• Space under its cover forms the inferior meatus.
• Includes the termination of the nasolacrimal duct.

Middle Concha

• Middle meatus includes the bulla ethamoidalis (a bony bulging).
• The middle ethmoidal air sinuses open into the meatus or above the bulla.
• Hiatus semilunaris: A Cresentric space below the bulla.
• Maxillary sinus opens into the posterior part of Hiatus semilunaris.
• Includes a short ethmoidal infundibulum passage at the anterior end of the hiatus.
• The anterior ethmoidal and frontal sinus opens into it.

Superior Concha

• Superior meatus: The posterior ethmoidal sinus opens here.
• Supreme meatus: Located between the superior concha and roof of the nasal cavity.
• Sphenoethamoidal recess: It is a depression above and behind the superior concha and sphenoidal air sinus opens.
• Shortest.

Nasal Passages

• Inferior meatuse: Nasolacrimal duct opens into this passage.
• Middle meatus: Frontal, maxillary, and ethmoidal cells open into this passage.
• Superior meatus: ethmoidal cells open into this passage.
• Sphenoethmoidal Recess: Sphenoidal sinus opens into this passage.

Lateral Wall Arterial Supply

• From the anterior ethmoidal, posterior ethmoidal, facial, and sphenopalatine arteries.

Lateral Wall Nerve Supply

• Opthalmic
• Anterior ethmoidal
• Maxillary
• Posterior superior lateral nasal (Pterygopalatine ganglion)
• Anterior superior alveolar
• Anterior palatine (Pterygopalatine ganglion)

Lateral Wall Special Sensory

• Olfactory Nerve

Clinical Notes - Applied Anatomy

• Infection can spread to the middle cranial fossa via the cribriform plate.
• Infection can spread to the lacrimal apparatus via the nasolacrimal duct.

Applied Anatomy

• Septal deviation of septum: can cause congestion, obstruction corrected by sub mucosal resection of the nasal septum.
• Epistaxis: Bleeding from nose.
• The nose is a dangerous area because infection spreads along olfactory nerves to the cranial cavity.
• Broken nose is a break or crack in the bone/cartilage in your nose.
• Breaks typically occur over the bridge of the nose or in the septum.

Little's Area

• Kiesselbach's plexus is located in Kiesselbach's area, Kiesselbach's triangle, or Little's area.
• Located in the anteroinferior part of the nasal septum.
• Four arteries join to form a vascular plexus.
• A common site of nosebleeds(Epistaxis).

Rhinitis (Allergic) - Applied Anatomy

• Mucosa of the inferior nasal concha experiences hypertrophy.

Pharynx

• The pharynx measures 12–14 cm in length.
• Musculomembranous tube that's shaped like a cone.
• It extends from the cranial base to the lower border of the cricoid cartilage (at the sixth cervical vertebra), which is continuous with the esophagus.
• It sits behind and connects with the nasal, oral, and laryngeal cavities through the nasopharynx, oropharynx, and laryngopharynx, respectively.
• It is divided into: the nasopharynx, oropharynx, & laryngopharynx.
• The oral cavity & pharynx join at the oropharyngeal isthmus

Nasopharynx features:

• Opening of the auditory tube
• Tubal elevation
• Salpingopharyngeal & salpingopalatine fold
• Tubal tonsil & Pharyngeal tonsil (adenoids)
• Communication between nose & oropharynx is the pharyngeal isthmus

Oropharynx features:

• Lies in front of C2 & upper part of C3 vertebra
• Palatopharyngeal folds/arches
• Palatine tonsil & tonsillar sinus

Laryngopharynx features:

• Lies in front of C3-C6 vertebra
• Upper part formed by inlet of larynx
• Inferior and posterior surfaces by arytenoid & cricoid cartilages.
• Wall of pharynx is formed by skeletal muscles & fascia
• Buccopharyngeal fascia coats outside of muscle wall
• Pharyngobasilar fascia lines inside of the muscle wall.

Pharynx - Muscle & Nerve Supply

• Constrictors: superior, middle, & inferior constrictors originate posterior to the cavities and meet with midline raphe.
• Longitudinal muscles: stylopharyngeus, palatopharyngeus & salpingopharyngeus.
• Nerve supply: all constrictors & salpingopharyngeus by pharyngeal branch of vagus.
• Stylopharyngeus by glossopharyngeal.
• Palatopharyngeus by cranial part of accessory.

Blood Supply, Lymphatics, and Nerve Supply

• Blood vessels & lymphatics: ascending pharyngeal, lingual, facial, maxillary arteries, venous plexus drains into internal jugular & facial veins, and lymph vessels drain into deep cervical lymph nodes.
• Pharyngeal plexus formed by branches of glossopharyngeal, vagus, & cranial accessory contribute to nerve supply.

Clinical - Killian’s Dehiscence

• Killian's dehiscence (Killian's triangle) a triangular area in the pharynx wall.
• Situated between the thyropharyngeal and cricopharyngeus in the pharynx.
• A weak spot for pharyngoesophageal diverticulum (Zenker's diverticulum).

Paranasal Air Sinus

• Air filled spaces in bones surrounding the nasal cavity.
• Named according to bones in which they are located.
• Have four groups of sinuses:
• Maxillary(Antrum of Highmore)
• Ethmoid
• Frontal
• Sphenoid

Additional notes on Sinuses

• The paranasal sinuses are cavities in the maxilla, frontal, sphenoid, and ethmoid bones.
• Lined with mucoperiosteum and filled with air.
• Communicate with the nasal cavity through small apertures. Lined by pseudostratified ciliated columnar epithelium.
• Aerated at birth: Maxillary sinuses
• Age 6-7: Frontal /sphenoidal sinuses.
• Ethmoid: develops after puberty and develops slowly until approximately 17-18 years of age.

Paranasal Air Sinus and Airways - Applied Anatomy

• Sinusitis is the inflammation of sinuses and may be acute, subacute, chronic and recurrent.
• Common causes of sinusitis: also common cold, allergic rhinitis, nasal polyp and deviated nasal septum.
• Open to: Inferior meatus: Nasolacrimal duct Middle meatus: Frontal & Maxillary sinus, Anterior & Middle ethmoidal cells Superior meatus: Posterior ethmoidal cells Sphenoethmoidal Recess: Sphenoidal sinus

Paranasal Air Sinus - Functions

• Functions of paranasal sinuses include decreasing skull bone weight, warming and moistening incoming air, acting as resonating chambers for voice, as shock absorbers, and may help control the immune system.
• The quality of voice is changed when the apertures of the sinuses are blocked or they become filled with fluid.
• Decrease skull bone weight
• Warm, moisten and filter incoming air
• Serve as a resonating chamber for voice
• Act as shock absorbers in trauma (like air bags in a car)
• Possibly help control Immune system

Trachea and Bronchial Tree

• Trachea and Bronchial Tree

References

• Textbook list