Basic topography of the upper respiratory tract Flashcards
What are the functions of the upper respiratory tract?
Humidify, warm and filter air
What are the bounderies of nasal cavities?
anterior- external nares
posterior- internal nares- opens into nasopharynx
medial- nasal septum- cartilage (ant. 1/3), vomer, perpendicular plate of ethmoid
Lateral- conchae
- Sup, Mid- ethmoid
- Inf. conchae
- Others
- Nasal
- Maxilla
- Lacrimal
- palatine
- sphenoid
Floor- palatine process of maxilla, horizontal plate of palatine
Roof- Nasal, nasal part of frontal, cribiform plate (ethmoid), sphenoid
Nasal septum
Ant 1/3- greater alar carulage and septal cartilage
Post 2/3- ethmoid+ vomer
How is the nasal cavity seperated from the cranial cavity?
Frontal, ethmoid and sphenoid
Describe the route of drainage for:
- Frontal sinus
- Maxillary sinus
- Ethmoid sinus-
- ant,
- mid,
- post
- Sphenoid sinus
- Frontal sinus- semi lunar hiatus- mid. meatus
- Maxillary sinus- semi lunar hiatus- mid. meatus
- Ethmoid
- Ant- semi lunar hiatus- mid. meatus
- Mid- ethmoid bulla- mid. meatus
- Post.- sup. meatus
- Sphenoid sinus- sphenoethmoidal recess
What are the 4 tonsils that make up the Waldeyers’s ring
- Palatine - between palatoglossal and palatopharyngeal archs
- Lingual- posterior base of the tongue
- Tubal- around the euchstachian tube
- Pharyngeal- (adenoids) roof of phraynx
What is the function of eustachian tube and which muscles open it>
equalise the pressure in the middle ear with the atmosphere
- Salpingopharyngeus
- muscles of soft palate- levator veil palatini, tensor veil palatini
What are the circular muscles of the pharynx?
Circular (All vagus)
- Superior pharyngeal constrictor- oropharynx, from pterygoid hamulus, pterygomandibular raphe, the mandible and the side of the tongue to the pharyngeal tubercle of occiput
- Middle pharyngeal constrictor- laryngopharynx- stylohyoid ligament and the horns of hyoid to the pharngeal raphe
- Inferior pharyngeal constrctor- laryngopharynx- Superior component- oblique fibres -attach to thyroid cartilage. Inferior componenet- horizontal fibres- attach to cricoid cartilage
What are the longitudinal muscles of pharynx?
- Stylopharyngeus- styloid process of temporal bone to pharynx (CN IX- glossopharyngeal)
- Palatopharyngeus- hard palate to pharynx (CNX- vagus)
- Salpingopharyngeus- eustachian tube to pharynx (CNX- vagus)
Which sinus is particularly susceptible to sinusitis and why?
Maxillary sinus because the frontal and anterior ethnoidal sinuses also drain into the nasal cavity via the semilunar hiatus
Infection in the ethmoidal sinuses often cause infection in other paranasal sinuses. Why?
Ethmoid sinus drain into three places, all of which are near the other sinuses
The ethmoid bones are thin and fragile and therefore liable to injury- a broken nose. Such injury often causes the nasal septum to deviate form the midline. what respiratory dysfunction might result?
diffuculty breathing through the nose, noisy breathing at night
infrequently, sharp foreign bodies are swallowed and become lodged in the laryngopharynx and may perforate the wall, resulting in infection. If the posterior wall is damaged, bacteria may enter the retropharyngeal space and may result in tracking of infection into posterior mediastinum. Where is the retropharyngeal space?
Space between the pretracheal and prevertebral layers. The retropharyngeal space extends into the thorax, infection can spread to mediastinal contents
Why might a sore throat cause reduced hearing?
The infection can spread from the upper respiratory tract to the ear via the eustachian tube. Infection of the eustachian tube causes swelling of the mucous linings, and the tube becomes blocked. This results in diminished hearing.
Trauma to the rood of nasal cavity may result in clear non viscous fluid leaving the nose. What is it and is it a serious problem
Fracture of cribiform plate can penetrate the meningeal linings of the brain, causing leakage of cerebro-spinal fluid. Exposing the brian to the outsude enviroment like this increases the risks of mengitis, encephalitis and cerebral abscesses.
The olfatory bulb may also be damaged, leading to anosmia- loss of smell
What is the blood supply to the nasal cavity?
Internal carotid
- ophthalmic- anterior ethmoidal, posterior ethmoidal
External carotid
- maxillary- sphenopalatine( arises in the pterygopalatine fossa, enters nasal cavity via the sphenopalatine foramen)
- maxillary- greater palatine
- Facial- superior labial
Kiesselbach area- anterior part of nasal septum where arteries anastamoses
Pterygopalatine fossa and sphenopalatine foramen
