Nose, Nasal cavity

1
(No Transcript)
2
Nose, Nasal cavity Paranasal Sinuses
Dr. Zeenat Zaidi
3
Nose

• Only externally visible part of the respiratory
  system
• Has a free tip and is attached to the forehead by
  the root or the bridge
• Has two openings, the anterior (external) nares
  or nostrils, which lead to the nasal cavity
• Each nostril is bounded laterally by the ala and
  medially by the nasal septum

root
tip
ala
septum
external nares
4
Nose Structure

• Nose consists of bony cartilaginous framework
• Formed above by the
• Nasal bones
• Frontal processes of maxillae
• Nasal part of frontal bone
• Formed below by plates of hyaline cartilage,
  which include upper lower nasal cartilages and
  the septal cartilage

Nasal part of Frontal bone
5
Nasal Cavity

• Extends from the external (anterior) nares to the
  posterior nares (choanae)
• Divided into right left halves by the nasal
  septum
• Each half has a
• Floor
• Roof
• Lateral wall
• Medial wall (septum)

6

• Roof
• Is narrow formed (from behind forward) by the
• Body of sphenoid
• Cribriform plate of ethmoid bone
• Frontal bone
• Nasal bone cartilage
• Floor
• Separates it from the oral cavity
• Formed by the hard (bony) palate

7

• Medial Wall (Nasal Septum)
• Osteocartilaginous partition, only rarely lying
  in the midline
• Covered by the mucoperiosteum
• Formed
• Superiorly by the vertical (perpendicular) plate
  of ethmoid bone
• Posteriorly by the vomer bone
• Anteriorly by the septal cartilage

8

• Lateral Wall
• Shows three horizontal bony projections, covered
  by mucous membrane, the superior, middle
  inferior conchae (turbinates)
• The superior and middle conchae are parts of the
  ethmoid bone, whereas the inferior concha is a
  separate bone
• The cavity below each concha is called a meatus
  and are named as superior, middle inferior
  corresponding to the conchae

9

• The small space above the superior concha is
  called the sphenoethmoidal recess
• The middle meatus is continuous in front with a
  depression called the atrium
• Atrium is limited bove by a ridge called agar
  nasi
• Below and in front of atrium, and just within the
  nostril lies the vestibule

10

• The conchae increase the surface area of the
  nasal cavity
• The recess meati receive the openings of the
• Paranasal sinuses
• Nasolacrimal duct

11

• Sphenoethmoidal recess Receives the opening of
  the sphenoidal sinus
• Superior meatus Receives the opening of the
  posterior ethmoidal sinus
• Inferior meatus Receives the opening of the
  nasolacrimal duct. The opening is guarded by a
  valve, a fold of mucous membrane

12

• Middle meatus
• Shows a rounded eminence, the ethmoidal bulla,
  caused by the bulging of the underlying middle
  ethmoidal sinus, which opens on its upper border.
• A curved groove, hiatus semilunaris, lies below
  the bulla. Hiatus receives the opening of the
  maxillary sinus
• Anterior end of hiatus leads to funnel-shaped
  infundibulum, which receives the openings of the
  frontal the anterior ethmoidal sinuses

13
Lining of the Nasal Cavity

• Vestibule is lined by modified skin, and has
  short, curved hair called vibrissae
• The roof, upper part of the septum, upper surface
  of the superior concha, and the sphenoethmoidal
  recess are lined by the olfactory mucosa
• The rest of the cavity is lined by the
  respiratory mucosa

A
V
V
14
Olfactory Mucosa

• Contains olfactory cells (bipolar sensory
  ganglion cells), which serve as receptors for
  olfactory stimuli.
• Distinct smells are far more numerous than tastes
• The sense of smell plays a major role in the
  flavor of foods and it is common for individuals
  who lose their sense of smell to report that food
  loses its taste. (food seems somewhat tasteless
  when a person has cold)
• Most air breathed in normally flows through the
  nose but only a small part reaches the olfactory
  mucosa, enough to get a response to an odor.
  Sniffing, however, increases the flow of air over
  the smell receptor cells, greatly increasing
  their exposure to odors.

15
Respiratory Mucosa

• Pseudostratified ciliated columnar epithelium
  with goblet cells
• Rests on thick network of thin walled veins that
  warms the air as it flows through the cavity
• Glands produce mucus, which
• moisten the air
• cleans the air by trapping the incoming bacteria
  and foreign debris
• Cilia help in moving the contaminated mucus
  posteriorly towards the throat, where it is
  swallowed and digested by the stomach juices

16
Nerve Supply

• Nasal cavity receives sensory visceral
  innervation
• Sensory innervation
• Olfactory mucosa supplied by olfactory nerves
• Nerves of general sensation are derived from
  opthalmic maxillary nerves
• Anterior part supplied by the anterior ethmoidal
  nerve (branch of opthalmic nerve)
• Posterior part supplied by nasal, nasopalatine
  and palatine branches (of maxillary nerve)

17

• Visceral Innervation
• Sympathetic fibers arise from neurons of superior
  cervical ganglion and are distributed through
  plexuses around the arteries, supply mainly
  vascular smooth muscle
• Parasympathetic fibers arise from neurons of the
  pterygopalatine ganglion that course in the
  nasopalatine nerve (branch of maxillary) and its
  branches, supply the mucosal glands.

18
Arterial Supply

• Sphenopalatine artery (branch of the maxillary
  artery) is the main supply
• Alar and septal branches of superior labial
  artery (branch of the facial artery)
• Anterior posterior ethmoidal arteries (branches
  of the ophthalmic artery)
• The arteries make a rich anastomosis in the
  region of the vestibule, and anterior portion of
  the septum

19

• Venous Drainage
• Veins begin as a rich plexus in the submucosa,
  accompany the corresponding arteries, and drain
  into the facial, ophthalmic, and sphenopalatine
  veins.
• Lymphatic Drainage
• The lymphatics from the
• Vestibule drain into the submandibular lymph
  nodes
• Rest of the cavity drains into the upper deep
  cervical lymph nodes

20
Functions of Nose Nasal Cavities

• Air conditioning warming, cleaning and
  humidifying the inhaled air
• Add resonance to the voice
• Vocal sounds are also produced in the nasal
  cavity thus aiding in vocalisation
• Involved in the special sense of smell
• Central role of the nose in facial appearance
• ??

21
Paranasal Sinuses

• Air filled cavities located in the bones around
  the nasal cavity ethmoid, sphenoid, frontal
  bones maxillae
• Lined by respiratory mucosa which is continuous
  with the mucosa of the nasal cavity
• Drain into the nasal cavity through relatively
  small apertures
• Drainage of the sinuses mainly depends on the
  movement of the cilia, which propel the mucus
  toward their openings in the nasal cavity

22

• The development of sinuses begins in 3-4 month,
  but only maxillary ethmoid sinuses are present
  in rudimentary form at birth. The frontal
  sphenoidal sinuses are not clinically perceptible
  at birth and can rarely be demonstrated on plain
  x-ray before two years of age.
• Continue to grow postnatally
• Enlarge appreciably after 8th year become fully
  formed at adolescence

E
M
From a 3 months old fetus, showing ethmoid
maxillary sinuses
23
Functions

• Lighten the skull
• Act as resonant chambers for speech
• The respiratory mucosal lining helps in warming,
  cleaning and moistening the incoming air

24
Maxillary Sinuses

• Located within the body of the maxilla
• Pyramidal in shape with the base forming the
  lateral wall of nose the apex lies in the
  zygomatic process of the maxilla
• Roof formed by the floor of the orbit
• Floor formed by the alveolar border. Roots of
  1st and 2nd premolars and the 3rd molar
  (sometimes canines) project into the sinus
• Opens into the middle meatus through the hiatus
  semilunaris
• Supplied by superior alveolar infraorbital
  nerves

M
25
Frontal Sinuses

• Two in number
• Located within the frontal bone, separated from
  each other by a bony septum
• Triangular in shape, extending backward into the
  roof of the orbit
• Opens into the middle meatus through the
  infundibulum
• Supplied by the supraorbital nerve

26
Ethmoidal Sinuses

• Located within the ethmoid bone, between the nose
  and the orbit
• Divided into three groups anterior, middle
  posterior
• Anterior group opens into the infundibulum,
  middle opens on the bulla, and posterior into the
  superior meatus
• Supplied by the anterior and posterior ethmoidal
  nerves

27
Sphenoidal Sinuses

• Two in number
• Located within the body of sphenoid
• Open into the sphenoethmoidal recess
• Supplied by the posterior ethmoidal nerve

28
Clinical Notes

• Epistaxis Littles area, common site of bleeding
  from nose
• Inflammation of the nasal mucosa, Rhinitis,
  results in nasal congestion and excessive
  production of mucus leading to postnasal drip
• Infections of the nasal cavity can extend to the
• Paranasal sinuses
• Nasolacrimal duct lacrimal sac

29

• Inflammation of mucosa of the sinuses, Sinusitis,
  causes excessive production of mucus leading to
  obstruction of the drainage of sinuses. This
  results in headache and change in the voice
• Infection of frontal anterior ethmoidal sinus
  can easily spread to maxillary sinus because of
  the location of their openings
• Infection of upper teeth can lead to inflammation
  of the maxillary sinus
• Extraction of an infected upper tooth may result
  in a fistula

30

• The maxillary sinus is most commonly the site of
  infection
• The inflamed mucosa results in excessive
  production of mucus as well as narrowing of its
  opening in the nasal cavity
• The position of the drain causes problems in that
  mucus can collect in the sinus below the drain.
  In this situation, the sinus will only drain if
  the patient lies on their opposite side.
• Pressure from the trapped fluid/mucus causes
  sinus pain

31
Thank You Good Luck