Nose, Nasal cavity & Paranasal sinuses Flashcards
Nose
Part of respiratory system that contains organ of smell
Location: superior to hard palate
Parts
- External nose
- Nasal cavity (R & L; nasal septum)
Functions
- Olfaction
- Respiration
- Filtration of dust
- Humidification of inspired air
- Reception and elimination of secretions from paranasal sinuses and nasolacrimal ducts
external nose
- Visible portion of nose that projects from the face
- Skeleton is mostly cartilaginous
- Skin covers all the nose, including the vestibule
- Parts
- Dorsum: from root superiorly to apex (tip) anteroinferior
- Nares (nostrils) inferior openings of the nose in the anterior aspect
- Alae (wings): bound nares laterally
- Vestibule: initial part of nasal cavity lined with skin. Hairs in the vestibule help filter dust particles
*nose (lateral & anterior view)
skeleton of external nose
- Skeleton
- Bones: nasal, frontal, and frontal process of maxillae
- Cartilages
- Lateral (2)
- Alar (2): moveable by muscles acting on nose
- Septal (1)
*skeleton of external nose
septum of external nose
- Septum
- Divides nasal chamber into two nasal cavities
- Components
- Bones: perpendicular plate of the ethmoid & vomer
- Cartilage: septal cartilage
nasal cavities
Location: superior to hard palate; communicates anteriorly (with the exterior) through nares, and posteriorly (with nasopharynx) through choana
Mucosa
- Lines the nasal cavities, except the vestibule (lined with skin)
- Olfactory mucosa: superior 1/3rd. Contains peripheral organ of smell
- Respiratory mucosa: inferior 2/3rd. Warms and moisturizes air before passing to lungs
Boundaries
- Roof: is curved and narrow, except at the posterior end, and it has three parts named after the bones that form them
- Frontonasal
- Ethmoidal
- Sphenoidal
- Floor: wider than the roof, formed by the palatine process of the maxilla and the horizontal plate of the palatine bone (hard palate)
- Medial wall: formed by the nasal septum
- Lateral wall: made of the scroll-shaped elevations called the nasal conchae
*nasal cavities
Turbinates
conchae covered on mucosa. Offer vast surface for heat exchange. Superior, middle, and inferior conchae
Nasal meatus
- passages underlying each of the turbinates
- Sphenoethmoidal recess
- Superior nasal meatus
- Middle nasal meatus
- Inferior nasal meatus
- Common nasal meatus
Sphenoethmoidal recess
Sphenoethmoidal recess: superoposterior to superior concha
- Opening of sphenoidal sinus
Superior nasal meatus
Superior nasal meatus: between superior and middle conchae
- Opening(s) of posterior ethmoidal sinuses
Middle nasal meatus
Middle nasal meatus: between middle and inferior conchae.
- Ethmoidal infundibulum: communication with frontal sinus via the frontonasal duct
- Semilunar hiatus: semicircular groove with openings of frontal, anterior ethmoidal, and maxillary sinuses
- Ethmoidal bulla: rounded elevation superior to the hiatus, contains opening of the middle ethmoidal sinus
Inferior nasal meatus
Inferior nasal meatus: inferolateral to inferior nasal concha
- Opening of nasolacrimal duct in anterior portion
Common nasal meatus
Common nasal meatus: medial part of nasal cavity, between nasal conchae and septum, where lateral recesses and meatus open
arteries of nasal cavity
- Ophthalmic a.
- Anterior and Posterior ethmoidal aa.
- Maxillary a.
- Sphenopalatine a.
- Greater palatine a.
- Facial a.
- Septal branch of the superior labial a.
- Kiesselbach area: anterior part of nasal septum where arteries anastomose
veins of nasal cavity
- Submucosal venous plexus drains into:
- Sphenopalatine v.
- Facial v.
- Ophthalmic v.
*vasculature of nasal cavities
nerves of nasal septum
- Olfactory (CN I)
- Trigeminal (CN V)
- Nasopalatine n. (V2)
- Anterior ethmoidal n. (V1)
*nerves of nasal septum
nerves in lateral wall of nasal cavity
- Posterior superior and inferior lateral branches (V2)
- Greater palatine nerve (V2)
- Anterior ethmoidal n. (V1)
*nerves in lateral wall of nasal cavity
Paranasal sinuses
- Air-filled extensions of the respiratory part of the nasal cavity
- Communicate with the nasal cavity through openings beneath the conchae on the lateral wall of the nasal cavity
(2) frontal sinuses
- Posterior to superciliary arches and root of nose
- R & L drain through a frontonasal duct in the ethmoidal infundibulum, which opens in the semicircular hiatus
(3-18) ethmoidal cells sinuses
- Fragile and easily shattered on hard impact. Medial to orbit and lateral to nasal cavity
- Divisions
- Anterior: drains into the infundibulum
- Middle: drains into ethmoidal bulla
- Posterior: superior nasal meatus
(2) sphenoid sinuses
- 1 on each side within the body of the sphenoid bone, inferior to the sella turcica
- Drain into the sphenoethmoidal recess
- Clinical relevance: inflammation in this sinus is a serious medical condition requiring immediate attention, with either antibiotics or direct cleaning of the sinus
(2) maxillary sinuses
- Largest of the paranasal sinuses
- lies in the prominence of the cheek within the maxilla, lateral to nasal cavity.
- Clinical relevance: infraorbital n. (CN V2) runs along the mucosa of the maxillary sinus to go to the upper teeth. Swelling in this sinus can make the teeth hurt, but is not a dental problem.
- Drain into the middle nasal meatus. Drainage is in the superior aspect of the sinus, which it makes it hard to drain.
*paranasal sinuses
*paranasal sinuses
nerves & vessels of sinuses:
frontal sinuses:
ethmoid sinuses:
sphenoid sinuses:
maxillary sinuses:
- Frontal sinuses: supraorbital nerve and artery
- Ethmoid sinuses: anterior and posterior ethmoidal arteries and nerves
- Sphenoid sinuses: posterior ethmoidal arteries and nerves
- Maxillary sinuses: anterior, middle, and posterior superior alveolar nerves and arteries
