Anatomy of the Nasal Cavity

Nasal Cavity

• The nasal cavity consists of the vestibule, olfactory region, and respiratory region.
• The nasal septum separates the nasal cavity into two halves.

Paranasal Sinuses

• The paranasal sinuses include:
  • Maxillary sinus
  • Frontal sinus
  • Sphenoidal sinus
  • Anterior ethmoidal sinus
  • Middle ethmoidal sinus
  • Posterior ethmoidal sinus
  • Superior ethmoidal sinus

Nasal Meatus and Nasolacrimal Duct

• The nasal meatus is a passage in the nasal cavity.
• The nasolacrimal duct connects the eye to the nasal cavity.

Pharynx

• The pharynx is divided into three parts:
  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• The pharynx contains the pharyngeal tonsil (third tonsil or adenoid) and the Eustachian salpinx (auditory tube).

Larynx

• The larynx is located at the level of C3-C6 and performs three main functions:
  • Respiratory duct
  • Swallowing
  • Phonation (voice production)
• The larynx is composed of several cartilages, including:
  • Single cartilages: thyroid, epiglottis, and cricoid
  • Paired cartilages: arytenoid, corniculate, and cuneiform
• The larynx contains laryngeal muscles and the vestibular fold and vocal fold.

Phonation

• Phonation involves the production of sound through the vibration of the vocal folds.
• The larynx is the source of energy for phonation, using the exhaled air.
• The vocal folds and the cavities of the mouth, nose, and sinuses modify and amplify the sound.

Laryngeal Ventricle

• The laryngeal ventricle is a small cavity between the vestibular and vocal folds.

Sex Differences

• The larynx of males and females differ in size:
  • Male: longitudinal diameter 44 mm, transverse diameter 43 mm, sagittal diameter 36 mm, and rima glottidis 23 mm
  • Female: longitudinal diameter 36 mm, transverse diameter 41 mm, sagittal diameter 26 mm, and rima glottidis 17 mm