Anatomy of the Respiratory System

Anatomy of the Respiratory System

# Nose

• How many parts is the nose divided into?

• The nose is divided into 2 parts: the external nose and the nasal cavity.

• The external nose includes:

• Nasal bones

• Nasal septum cartilage

• Lateral nasal cartilage

• Greater alar cartilage

• Lesser alar cartilage

• The roof of the nasal cavity includes:

• Nasal bone

• Nasal spine of the frontal bone

• Horizontal plate of the ethmoid bone

• Body of the sphenoid bone

• The floor of the nasal cavity includes:

• 3/4 of the external maxillary bone

• 1/4 of the palatine bone

• The medial wall of the nasal cavity includes:

• Perpendicular plate of the ethmoid bone

• Nasal septum cartilage

• Vomer bone

• Palatine bone

• Maxillary bone

• The lateral wall of the nasal cavity includes:

• Maxillary bone

• Lacrimal bone

• Lateral mass of the ethmoid bone

• Sphenoid bone

• Vertical plate of the palatine bone

• Respiratory mucosa:

• Under the superior turbinate, 2/3 of the inferior nasal septum

• Continuous with the pharyngeal mucosa and the sinuses

• Olfactory mucosa:

• Above the superior turbinate and the upper 1/3 of the nasal septum

• Arteries supplying the nose:

• Anterior ethmoid artery

• Sphenopalatine artery

• Superior labial artery

• Nerve points of the nose:

• On the nasal septum, 1 cm away

• The superior nasal meatus drains into the middle nasal meatus:

• Frontal sinus

• Maxillary sinus

• Anterior ethmoid sinus

• Middle ethmoid sinus

• The posterior nasal meatus drains into the superior nasal meatus:

• Sphenoid sinus

• Posterior ethmoid sinus

# Pharynx

• Pharynx length:

• 12-14 cm

• Nasopharynx has:

• Pharyngeal tonsil in the vault of the pharynx

• Tubal tonsil on the lateral wall

• Oropharynx has:

• Palatine tonsil on the lateral wall

• Superior pharyngeal constrictor muscle:

• Attaches to the pterygoid hamulus and the medial aspect of the mandible

• Middle pharyngeal constrictor muscle:

• Attaches to the stylohyoid horns

• Inferior pharyngeal constrictor muscle:

• Attaches to the lateral surface of the thyroid cartilage, cricoid cartilage, and cricothyroid ligament

• Palatopharyngeal muscle:

• Hamulus to the lateral wall of the pharynx

• Salpingopharyngeal muscle:

• Eustachian tube to the wall of the pharynx

• Arteries supplying the pharynx:

• Ascending pharyngeal artery

• Pterygoid-palatine artery

• Ascending palatine artery

• Pharyngeal nerves:

• IX, X

# Larynx

• Thyrohyoid membrane:

• Superior margin of the thyroid cartilage -> inferior margin of the hyoid bone

• Has a hole for the thyroid gland branch of the superior thyroid artery and the superior laryngeal nerve to pass through

• Cricothyroid membrane:

• Inferior margin of the thyroid cartilage -> superior margin of the cricoid ring

• Quadrangular membrane:

• Vestibular ligament -> arytenoid cartilage

• Conus elasticus:

• Vocal ligament -> superior margin of the cricoid cartilage

• Vocal ligament:

• Vocal process -> angle of the thyroid cartilage

• Vestibular ligament:

• Anterior aspect of the arytenoid cartilage -> angle of the thyroid cartilage

• Cricothyroid muscle:

• Origin: external surface of the cricoid ring

• Insertion:

• Straight portion: inferior margin of the thyroid cartilage

• Oblique portion: inferior margin of the inferior horn of the thyroid cartilage

• Lateral cricoarytenoid muscle:

• Origin: superior margin of the cricoid ring

• Insertion: muscular process of the arytenoid cartilage

• Posterior cricoarytenoid muscle:

• Origin: posterior surface of the cricoid lamina

• Insertion: muscular process of the arytenoid cartilage

• Interarytenoid muscle:

• Origin: posterior surface of the 2 arytenoid cartilages

• Insertion: muscular process -> apex of the arytenoid cartilage

• Thyroarytenoid muscle:

• Origin: inner surface of the 2 thyroid laminae

• Insertion: anterior lateral aspect of the muscular process of the arytenoid cartilage

• Vocal muscle:

• Origin: angle of the thyroid cartilage

• Insertion: vocal process of the arytenoid cartilage

• Arteries supplying the larynx:

• Superior laryngeal artery

• Inferior laryngeal artery

• Superior laryngeal nerve:

• Motor to the cricothyroid muscle

• Vagus nerve (X):

• Motor to most of the laryngeal muscles

# Trachea

• Length of the trachea:

• 11-12 cm

• Esophagus, Vagus nerve (X):

• Located behind the trachea

• Arteries supplying the trachea:

• Inferior thyroid artery

• Bronchial branches of the thoracic aorta

• Nerves of the trachea:

• Vagus nerve (X)

# Bronchi

• Main bronchi separate at:

• Thoracic vertebra IV

• Why is the superior ethmoid sinus prone to pus accumulation?

• It’s 0.5-1 cm below the floor of the nasal cavity

• Muscle that opens the glottis:

• Posterior cricoarytenoid muscle

# Lungs

• Functional lung root includes:

• Pulmonary artery

• Pulmonary vein

• Main bronchus

• Nutritional lung root includes:

• Bronchial artery

• Bronchial vein

• Nerves from the pulmonary plexus

• Lymphatics

• Right pulmonary artery lies … to the right main bronchus?

• Anterior

• Left pulmonary artery lies … to the left main bronchus?

• Superior

• Superior pulmonary vein lies … to the main bronchus?

• Anterior

• Inferior pulmonary vein lies … to the main bronchus?

• Inferior

• The left bronchial artery branches from?

• Thoracic aorta

• Usually 2-3 arteries

• The right bronchial artery branches from?

• 3rd intercostal artery or the left bronchial artery

• Deep bronchial veins drain into?

• Pulmonary vein

• Superficial right bronchial vein drains into the azygos system?

• Superficial left bronchial vein drains into the accessory hemiazygos vein and intercostal veins

Note: This is just a summary of information about the anatomy of the respiratory system. For a deeper understanding of each part and its function, you need to consult specialized medical literature.