Paranasal Sinuses - Regional Anatomy Flashcards
What age do the frontal and sphenoid become visible on a radiograph
6/7 years of age
What sinus develops last
Ethmoid
What is it lined by
Nasal mucous membrane e.g. ciliated columnar epithelium
What are the paranasal sinuses?
- Maxillary (2) - maxillary (facial) bones
- Frontal (2) - frontal (cranial) bones
- Ethmoid (many) - ethmoid (cranial) bones
- Sphenoid (cranial) bones
Maxillary sinus
- frontal view - pyramidal shaped
- anteriorly - bounded by facial surface of maxilla
- posteriorly - related to pterygopalatine fossa
- opening of maxillary sinus is into nasal cavity between inferior and middle conchae
Maxillary sinus complications?
Complications:
• Walls of the maxilla are very thin
• They are usually paired and fairly symmetric in size and shape
• Complications can occur when extracting molars
• Oral Antral Fistula can occur
• Infection called sinusitis occurs
Frontal sinuses
- occupy frontal bone above superior surface of orbit, posterior to the glabella
- rarely become aerated before age 6
- rarely symmetric
- separated by a septum
Ethmoid sinus
- contained within the lateral masses or labyrinths of the ethmoid bone
- these air cells are grouped into anterior, middle and posterior collections but they all intercommunicate
- side view -anterior ethmoid sinuses appear to fill the orbits - because portions of the ethmoid sinuses are contained in the lateral masses of the ethmoid bone, which helps form the medial wall of each orbit
Sphenoid sinus
- lies in body of the sphenoid bone directly below the sella turcica
- body of sphenoid containing these is cubic and frequently divided by a thin septum to form two cavities - septum may be incomplete or absent entirely, however, resulting in only one cavity
Functions of paranasal sinuses
• Aid in cleaning nasal passages
• Providing resonance to voice
• Warming and moistening air
• Reducing total weight of head
• Insulating brain from temperature extremes
Lymphatic Drainage - where does the lateral wall of the nose drain into
Submandibular nodes
Lymphatic Drainage - where does the posterior part of the nasal cavity drain into
Retropharangeal and upper deep cervical lymph nodes
Nerve supply - frontal
Supplied by supraorbital nerve from ophthalmic from ophthalmic division of the trigeminal
Nerve supply - sphenoidal and ethmoidal
Supplied by ethmoidal branches of maxillary division of the trigeminal nerve
Nerve supply - maxillary
Supplied by branches of superior alveolar and infraorbital nerves from maxillary division of trigeminal nerve