Transcript Paranasal Air Sinuses and the URT

Great Vessels, Coronary aa,
Paranasal Air Sinuses and the URT
Harry Rhodes - 2011
Aims
1. Describe the position and supply of the great vessels
of the heart and the coronary aa
2. Follow the upper airway from the nasal cavity to the
larynx and name structures along the way
3. Examine the architecture of the nasal cavity and its
surroundings
4. Learn the structure and function of the 4 paranasal
sinuses
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Maxillary, frontal, ethmoidal, sphenoidal
Imaging
Recap of Cardiac
Blood Flow
The Aortic Arch and Its Branches
•
There are three main components
to the thoracic part of aorta:
– Ascending aorta
– Arch of the aorta
– Descending aorta
•
The arch of the aorta has three
main branches
– The brachiocephalic trunk
– Left common carotid artery
– Left subclavian artery
•
The brachiocephalic trunk splits
into
– Right subclavian aa  right upper
limb
– Right common carotid  right
head and neck
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Left common carotid aa  Left
head and neck
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Left subclavian  left upper limb
Superior and Inferior Vena Cava
• The SVC and IVC enter the right
atrium penetrating the pericardial
sac, draining the upper and lower
body of venous blood
• The IVC has to penetrate the
diaphragm (T8) in order to reach
the heart
• Left and right brachiocephalic
veins, which lie anterior to the
aortic arch branches, drain into the
SVC
• Left and right internal jugular veins
(draining the head and neck) and
subclavian veins (draining the
upper limb) feed into their
respective brachiocephalic veins
Coronary Supply
• There are two coronary aa
which supply the myocardium
– Left and right
– Arise from ascending aorta
(aortic sinuses)
– Circle the heart in the
coronary sulcus
– Have marginal and
interventricular branches
which merge near the apex of
the heart
• Venous blood is returned to
the coronary sinus in the right
atrium via the cardiac veins
Right Coronary Artery
• It is the most dominant of the
two arteries and supplies
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Right atrium and ventricle
SAN and AVN
Interatrial septum
Posteroinferior 1/3 of the
interventricular septum
– A portion of the posterior part
of the left ventricle
• Descends anteriorly and to the
right from the right aortic sinus
within the coronary sulcus,
continuing posteriorly
• Has three main branches:
– Atrial branch  SAN branch
– Right marginal branch 
towards apex
– Posterior interventricular
branch  base/ diaphragmatic
surface
Left Coronary Artery
• Arises from the left aortic
sinus and supplies:
– Most of the left atrium and
ventricle
– Most of the interventricular
septum (AV bundle and
branches)
• Splits into 2 main branches
between the pulmonary
trunk and left auricle:
– Anterior interventricular
branch (LAD)  apex
• Diagonal branches
– Circumflex branch  base/
diaphragmatic
• Left marginal branch
Overview of the URT
(Sphenoid
sinus)
(Frontal
sinus)
Nasal cavity
Uvula
Nasopharynx
Hard palate
Tongue
Oropharynx
Laryngopharynx
Laryngeal cartilages
The Nasal Cavities
• Uppermost part of the respiratory tract
• There are 2 cavities, separated by a midline septum
• Air flow travels from anterior nares to posterior choanae
• There are 3 key areas of the cavity
– Nasal vestibules
– Respiratory regions
– Olfactory regions
• They have 2 main functions:
– Respiration
– Olfaction
• Branches of the olfactory nerve* (CN I) innervate this region
• Sense of smell
Airflow: Conchae and Meati
Respiratory
epithelium
Clean,
warm
and
humidify
air
Organised passage
of air
Conchi Vs.
meati
Paranasal Sinuses
• Outgrowths from nasal cavities
and erode into surrounding bones,
named after their bone
• Lined by respiratory mucosa
(ciliated and mucous secreting)
• Open into nasal cavities
• Innervated by the trigeminal
nerve* (CN5)
• Function still unsure, several ideas:
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Warming/ humidifying air
Immune function
Lightening the skull
Change vocal resonance
• Frontal sinus
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Superior
One on each side
Triangular shaped
Bridge of the nose to
1/3 way along upper
margin of the orbit
– Drains into the lateral
wall of the middle
meatus via the
frontonasal duct
• Maxillary sinuses
• Ethmoidal cells
– Clusters of ‘mini
sinuses’ in the lateral
most parts of the
ethmoid bone 
labyrinths
– Between orbit and
medial wall of the
labyrinths
– Divided into anterior
middle and posterior
clusters
• Anterior  ethmoidal
infundibulum/
frontonasal duct
• Middle  ethmoidal
bulla or lateral wall just
above
• Posterior  lateral wall
of the superior nasal
meatus
– The largest of the sinuses
– Pyramidal shaped and occupy most of the maxillary bones
– Opens superiorly into the lateral wall of the middle meatus
via the hiatus semilunaris
Sphenoid Sinus
• There are 2 sinuses within
the body of the sphenoid
• Open into the nasal cavity
via apertures on the
posterior wall the
sphenoethmoidal recess
Paranasal Air Sinuses (Imaging)
Paranasal Air Sinuses (Imaging)
Great Vessels, Coronary aa,
Paranasal Air Sinuses and the URT
Harry Rhodes - 2011