ENT (Otorhinolaryngology) · MU Sofia

19. Clinical anatomy of the nasal cavity and sinuses. Physiology of the nose and paranasal cavities.

Covers the anatomy of the nasal cavity, including the septum, lateral wall with its meatuses and turbinates, roof, floor, arterial supply and nerve supply, followed by the drainage and relations of the paranasal sinuses. Then explains nasal physiology: warming, humidification, filtration and mucociliary clearance, the nasal cycle, sinus functions and the sense of smell. It closes with a short list of clinical correlations such as OMC blockage and cribriform plate fracture.

Inside: 4 sections · 5 labelled pictures · 14 flashcards · 7 min

Topic 19 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 4 sections, about 1,020 words (7 min of reading), with 14 flashcards.

In this note

  1. Clinical Anatomy of the Nasal Cavity and Sinuses. Physiology of the Nose and Paranasal Cavities
  2. E. Arterial Blood Supply (The Nasal Casket)
  3. II. Clinical Anatomy of the Paranasal Sinuses
  4. III. Physiology of the Nose and Paranasal Cavities

Clinical Anatomy of the Nasal Cavity and Sinuses. Physiology of the Nose and Paranasal Cavities

I. Clinical Anatomy of the Nasal Cavity

The nasal cavity is the superior-most part of the upper respiratory tract, extending from the vestibule (nostrils) to the choanae (posterior openings) where it communicates with the nasopharynx.

  • Divided into - Right and left halves
  • Separated by the nasal septum

Functions

  • Air conduction
  • Air conditioning
  • Olfaction
  • Resonance for speech
  • Defense

A. The Nasal Septum (Medial Wall)

The septum divides the nasal cavity into two halves.

  • Bony Components (Posterior):
  • Vomer
  • Perpendicular Plate of the Ethmoid (PPE)
  • Cartilaginous Component (Anterior/Inferior):
  • Quadrangular Cartilage (Septal Cartilage)
  • Clinical Significance:
  • Deviated Nasal Septum (DNS): A common condition where the septum is crooked, causing nasal obstruction.
  • Septal Hematoma/Abscess: Collection of blood/pus between the septal cartilage and its perichondrium. Must be drained immediately to prevent pressure-induced necrosis of the avascular cartilage, leading to a saddle nose deformity.

B. The Lateral Wall- most imp wall

  • Superior turbinate/concha
  • Superior meatus: Contains the drainage opening for the Posterior Ethmoidal Sinuses
  • Middle turbinate: Key landmark for ESS (Endoscopic Sinus Surgery). Its removal or injury can affect drainage.
  • Middle meatus: Contains the Osteomeatal Complex (OMC), the primary drainage area for the Maxillary, Frontal, and Anterior Ethmoidal Sinuses
  • Inferior turbinate: largest, target for reduction (turbinoplasty/turbinotomy) to improve breathing
  • Inferior meatus: Contains the opening of the Nasolacrimal Duct (tear duct), making it the site for DCR surgery
  • Sphenoethmoidal recess: Site of drainage of the Sphenoid sinus

Concha- 👉 Increase surface area and turbulence

C. The Roof: Formed by:

Nasal bone

Frontal bone

Cribriform plate of ethmoid

Sphenoid body

Clinical

Olfactory filaments pass through cribriform plate

Fracture → CSF rhinorrhea + anosmia

D. Floor: Formed by (hard palate): Palatine process of maxilla Horizontal plate of palatine bone Separates nasal cavity from oral cavity

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