Anatomy of the Diaphragm and Nasal Cavity

Diaphragm

• Innervation: Right and left phrenic nerves (motor to diaphragm, sensory to central diaphragm); lower five intercostal and subcostal nerves (sensory to peripheral diaphragm).
• Blood supply: Superior and inferior phrenic arteries, pericardiophrenic arteries, musculophrenic arteries, superior epigastric arteries, lower five posterior intercostal and subcostal arteries.
• Venous drainage: Superior and inferior phrenic veins, pericardiophrenic veins, musculophrenic veins, superior epigastric veins, lower five posterior intercostal and subcostal veins.
• Development: Septum transversum (central tendon), pleuroperitoneal membranes (domes), dorsal mesentery of esophagus (part around esophagus), body wall (peripheral part).
• Clinical correlations: Congenital diaphragmatic hernias (posterolateral, retrosternal, paraesophageal/rolling); acquired diaphragmatic hernias (traumatic, hiatal/sliding).

Pleura

• Structure: Parietal (outer) and visceral (inner) layers enclosing the pleural cavity; parietal layer is thicker.
• Pulmonary ligament: Loose areolar tissue, few lymphatics; provides space for inferior pulmonary vein expansion during high venous return.

Nose

• Parts: External nose and nasal cavity.
• Functions: Respiration, olfaction, protection of lower respiratory passages, conditioning inspired air, vocal resonance, nasal reflexes (e.g., sneezing).
• External nose: Clinical correlation – rhinophyma (sebaceous gland hypertrophy).
• Arteries of external nose: Dorsal nasal branch of ophthalmic artery, infra-orbital branch of maxillary artery, alar and septal branches of facial artery.
• Sensory nerve supply of external nose: External/dorsal nasal and infra-trochlear branches of ophthalmic nerve; infra-orbital branch of maxillary nerve.
• Muscles of external nose: Procerus (transverse wrinkles), nasalis (compressor naris, dilator naris), depressor septi; supplied by facial nerve.

Nasal Cavity

• Divisions: Vestibule and nasal cavity proper.
• Vestibule: Sweat glands, sebaceous glands, vibrissae (coarse hair); limen nasi (upper limit), columella (medial wall).
• Clinical correlation: Deviated nasal septum (DNS); corrected by submucous resection (SMR) or septo-plasty.
• Nasal conchae: Superior and middle (ethmoid bone), inferior (independent bone), supreme (sometimes present).
• Meatuses: Inferior (nasolacrimal duct), middle (ethmoidal air cells, infundibulum, maxillary sinus, frontal sinus), superior (sphenoidal sinus).
• Lining: Olfactory region (olfactory epithelium), respiratory region (pseudostratified ciliated columnar epithelium).

Arterial Supply of Nasal Cavity Lateral Wall

• Antero-superior quadrant: Anterior and posterior ethmoidal arteries (ophthalmic artery).
• Antero-inferior quadrant: Alar branch of facial artery and terminal branches of greater palatine arteries.
• Postero-superior quadrant: Sphenopalatine branch of maxillary artery.
• Postero-inferior quadrant: Greater palatine branch of maxillary artery.
• Overall: Branches of ophthalmic, maxillary, and facial arteries.

Venous Drainage and Lymphatic Drainage of Nasal Cavity Lateral Wall

• Venous drainage: Facial vein, retropharyngeal veins, pterygoid venous plexus.
• Lymphatic drainage: Submandibular, retropharyngeal, and upper deep cervical lymph nodes.

Little's Area and Arterial Supply of Nasal Septum

• Little's area (Kiesselbach's plexus): Septal branches of anterior ethmoidal, sphenopalatine, greater palatine, and superior labial arteries.
• Arterial supply of nasal septum: Antero-superior (anterior and posterior ethmoidal arteries), postero-inferior (sphenopalatine and greater palatine arteries), mobile part (septal branches of superior labial artery).
• Venous drainage of nasal septum: Superior ophthalmic vein, pterygoid venous plexus, internal jugular vein via facial vein.

Trachea

• Cartilage: Hyaline cartilage rings (posterior wall devoid of cartilage).
• Muscles: Outer longitudinal, inner circular smooth muscles (posterior wall).
• Adventitia: Outermost layer (connective tissue, blood vessels, nerves).
• Mucosa: Pseudostratified ciliated columnar epithelium; lamina propria (connective tissue, smooth muscle fibers, mucous and serous glands).

Bronchi

• Hyaline Cartilage: Outside lamina propria, in small pieces.

Bronchioles

• Mucosa: Simple columnar cells.
• Lamina propria: Connective tissue and smooth muscle fibers; lacks glands and cartilage.

Alveoli

• Lining: Simple squamous cells and secretory (type II) cells (surfactant).
• Alveolar phagocytes (dust cells).
• Blood Vessels: Pulmonary artery branches and pulmonary vein tributaries (simple squamous epithelium).

Intercostal Muscles

• Internal intercostal muscles (11 pairs): Intercostal nerve supply; elevates ribs during expiration.
• Intercostalis intimus (11 pairs): Intercostal nerve supply; elevates ribs during expiration.
• Transversus thoracis muscle, subcostalis: Intercostal nerve supply; depresses ribs.
• Sternocostalis: Intercostal nerve supply; draws down costal cartilages.
• Levatores costarum: Elevates and rotates ribs; rotates and laterally flexes vertebral column.
• Nerve supply: Ventral rami of thoracic spinal nerves.
• Clinical correlation: Herpes zoster.

Intercostal Arteries and Veins

• Arteries: Posterior intercostal arteries (1st-2nd: costocervical trunk; 3rd-11th: descending thoracic aorta); anterior intercostal arteries (1st-6th: internal thoracic artery; 7th-9th: musculophrenic artery).
• Veins: Anterior intercostal veins (1st-6th: internal thoracic vein; 7th-9th: musculophrenic vein); posterior intercostal veins (1st-4th: superior intercostal vein; 5th-11th: azygos and accessory hemiazygos veins).

Central Tendon of Diaphragm

• Trifoliate shape (anterior and two posterior leaflets).
• Fused with fibrous pericardium (superficial cardiac dullness).

Costodiaphragmatic Recesses

• Not filled by lung during quiet inspiration; partially filled during deep inspiration.
• Right recess: Related to liver and right kidney (separated by diaphragm).
• Left recess: Related to stomach fundus, spleen, and left kidney (separated by left kidney).

Parietal and Visceral Pleura

• Parietal pleura: Develops from somatopleuric mesoderm; pain sensitive; innervation (somatic nerves – intercostal and phrenic); arterial supply (intercostal, internal thoracic, musculophrenic arteries); venous drainage (azygos and internal thoracic veins); lymphatics (intercostal, internal mammary, posterior mediastinal, diaphragmatic nodes).
• Visceral pleura: Develops from splanchnopleuric mesoderm; pain insensitive; innervation (autonomic – sympathetic nerves T2-T5); blood supply (bronchial vessels); lymphatics (bronchopulmonary lymph nodes).

Clinical Correlations of Pleural Cavity

• Pneumothorax, hydrothorax, hydropneumothorax, hemothorax, empyema, pleurisy (pleuritis).

Lungs

• Color: Rosy pink (newborns, clean environment); mottled brown/black (polluted areas, smokers).
• Right lung: Shorter and broader (liver).
• Left lung: Longer and narrower (heart).

External Features of Lungs

• Apex (covered by cervical pleura and Sibson's fascia).
• Base/diaphragmatic surface.
• Costal surface (upper ribs in midclavicular, midaxillary, and scapular lines).
• Medial surface (vertebral and mediastinal parts).

Mediastinal Surface Grooves (Right Lung)

• Azygos vein, superior vena cava (SVC), inferior vena cava (IVC), esophagus, eparterial bronchus, hyparterial bronchus.

Lobes and Fissures of Lungs

• Right lung: Superior, middle, inferior lobes; oblique and horizontal fissures.
• Left lung: Superior, inferior lobes; oblique fissure.

Hilum of Lungs

• Right: Eparterial bronchus, right pulmonary artery, hyparterial bronchus, superior and inferior pulmonary veins.
• Left: Left pulmonary artery, bronchus, superior and inferior pulmonary veins.

Arterial Supply and Venous Drainage of Lungs

• Arterial supply: Bronchial and pulmonary arteries.
• Venous drainage: Bronchial (deoxygenated) and pulmonary (oxygenated) veins.
• Lymphatic drainage: Bronchopulmonary (hilar) lymph nodes.

Test your knowledge on the anatomy and functions related to the diaphragm and nasal cavity. This quiz covers key concepts including motor functions, blood supply, and relevant conditions that affect these structures. Perfect for students studying human anatomy or related medical fields.