Respiratory anatomy (including clinical scenarios) Flashcards
What are the boundaries of the anterior triangle of the neck?
superior boundary = inferior border of mandible
posterior boundary = anterior margin of sternocleidomastoid
anterior boundary = midline of neck
What is the function of the infrahyoid and suprahyoid muscles?
suprahyoid muscles = elevate hyoid/larynx
infrahyoid muscles = depress hyoid/larynx
Which cranial nerves do the laryngeal nerves branch from?
laryngeal nerves are branches of cranial nerve 10 (vagus nerve)
Which group of muscles does the recurrent laryngeal nerve innervate?
all of intrinsic muscles of the larynx (except for cricothyroid)
What are enclosed in the pretracheal fascia?
thyroid gland and trachea
How can the thyroid gland and trachea being enclosed in the pretracheal fascia cause a potential problem following a thyroidectomy?
fascia surrounds the thyroid gland, trachea and pharynx forming an enclosed space
if a vessel is damaged during a thyroidectomy, blood can fill this space, leading to an onset of asphyxiation and airway compromise
What are pleurae?
fluid-secreting membranes that line the internal thoracic wall, diaphragm, mediastinum and external surface of the lungs
What is the function of the parietal and visceral pleura?
produce serous fluid that allows the lungs to slide smoothly against the chest wall
surface tension of the pleural fluid provides the cohesion that keeps the lung surfaces in contact with the thoracic wall, resulting in the lungs expanding and filling with air when the thorax expands
What is the innervation of the parietal and visceral pleurae and why may this be clinically relevant?
parietal = somatic innervation
visceral = autonomic innervation (not very sensitive or specific to pain)
clinical relevance = a lesion/tumour affecting lung tissue (covered by visceral pleura) will not present as a sharp, localised pain
if it spreads and invades/comes into contact with the parietal pleura, the pain will become sharp and highly localised
What is the normal function of the costodiaphragmatic and costomediastinal recesses?
act as potential spaces for the lungs to expand into during forces inspiration
Why can the costodiaphragmatic and costomediastinal recesses be important clinically?
pleural effusions collect in the costodiaphragmatic recess when in the standing position
pleural taps often work in this space as there is a decreased risk of puncturing the lung
Which peripheral nerve (and nerve roots) innervate the diaphragm?
phrenic nerve (C3, C4, C5)
[3, 4, 5 keep the diaphragm alive)
Where might irritation of the diaphragm present referred pain to?
C3 and C4 also supply supraclavicular nerves, whilst C5 forms the upper root of the brachial plexus and receives sensation from the lateral arm and shoulder region
irritation of the diaphragmatic pleura or peritoneum can present as pain in the region above the clavicle and shoulder tip
What neurovascular structures lie in the groove between the attachments of the anterior and middle scalene muscles?
trunks of the brachial plexus
subclavian artery
What are the names of the 2 actions of rib movement?
pump handle action = intercostal muscles acting on upper ribs contract, rib cage expanded in antero-posterior plane
bucket handle action = lower ribs take a more oblique course from posterior to anterior, when the intercostal muscles pull on these ribs, they tend to swing out laterally
How do we cause air to move into the lungs?
increase intrathoracic volume
this drops the pressure below atmospheric pressure
air will move into the lungs in any way it can to equalise the pressure
Which muscles are involved in quiet respiration?
primarily the diaphragm
with assistance from the intercostals/scalene if needed
What are the accessory muscles of respiration?
sternocleidomastoid
pectoralis major
serratus anterior
latissimus dorsi (inspiration)
abdominal muscles (expiration)
What is a pneumothorax?
air in pleural cavity
What is a tension pneumothorax?
the opening in the pleura creates a flap that acts as a one-way valve
this allows air to enter the cavity during inspiration, but stops it from leaving during expiration
What is a haemothorax?
blood in the pleural cavity
What is a pleural effusion?
liquid in pleural cavity (commonly as a result of infection)
What is the difference between a primary and secondary spontaneous pneumothorax?
primary spontaneous pneumothorax = develops for no apparent reason in an otherwise healthy person, usually young adult
thought to be due to tiny tear of an outer part of the lung, commonly near the apex of the lung
secondary spontaneous pneumothorax = develops as a complication (a secondary event) of an existing lung disease
Briefly describe what happens during a spontaneous pneumothorax
small bleb/weakness ruptures - more common in tall patients
air in pleural space can result in pain - variable in intensity
feeling of breathlessness
air in pleural space may result in lung collapsing
Tension pneumothorax treatment
immediate decompression = inserting a needle into the thoracic cavity
When inserting a needle into an intercostal space, why should it be passed along the superior border of the rib?
to avoid hitting the neurovascular bundle in the costal groove on the inferior surface of the rib
What is the key landmark for insertion of a needle in a pneumothorax?
2nd intercostal space in the mid-clavicular line
What is the common surface landmark for needle insertion in a pleural effusion or haemothorax?
the ‘safe triangle’
5th intercostal space, at the upper border of the rib, just anterior to the mid-axillary line
What structures are at risk when inserting a needle at these locations within an intercostal space:
- 2nd intercostal space midclavicular
- 5th intercostal space just anterior to the mid-axillary line
2nd intercostal space midclavicular:
- if too medial, the internal thoracic vessels are at risk
5th intercostal space just anterior to the mid-axillary line:
- if too posterior, the long thoracic nerve is at risk
How can a lung cancer cause a hoarse voice?
right laryngeal nerve loops around right subclavian artery and ascends to innervate intrinsic muscles of larynx
compression of nerve by space-occupying lesion will cause vocal cords on affected side to be paralysed
How can a lung cancer cause wasting of intrinsic muscles of the hand?
intrinsic muscles of hand innervated by nerves carrying T1 nerve root
lower trunk of brachial plexus carries C8/T1 nerve roots and is related to the apex of the lung where the tumour has formed. causing compression of the trunk
If a tumour develops in the apex of the left lung, will the patient suffer from voice hoarseness?
no
recurrent laryngeal nerve on left loops around the aorta
Which structures are likely to be compressed to cause right eyelid drooping, right pupil contraction that doesn’t respond to reduced light, and absence of sweating on face and forehead?
right cervical sympathetic plexus or ganglion
provides sympathetic innervation to the head + neck
related to apex of lung (so can be affected in lung cancer)
muscles that dilate pupil paralysed
levator palpebrae superioris muscle lost sympathetic innervation, only has innervation from CN 3 and so can’t work as effectively
sweat glands will not secrete due to loss of innervation
How does each bronchopulmonary segment work semi-independently?
they have their own bronchus, arterial supply and venous drainage
cen resect one bronchopulmonary segment without affecting the function of the others
Why must a thoracic surgeon know the 3D anatomy and numbers of the segments when doing a flexible bronchoscopy?
vital for orientating yourself
if anything found (eg. a tumour), you can identify lobe and plan resection
Why would a chest physiotherapist treating CF patients need to know the 3D anatomy of the bronchi?
CF causes sticky mucus to build up in lungs and digestive system
clearing this mucus requires lungs to be drained under gravity
therefore, understanding 3D anatomy of bronchi is necessary to place patients in correct position to drain each segment
What’s the most likely location of an aspirated foreign object and why?
right main bronchus/right lower secondary bronchus
right main bronchus is wider, shorter and more vertically-orientated than left, therefore more likely foreign bodies will enter right bronchus
if small enough, objects may continue to right secondary lower bronchus
If someone stops breathing when choking, where is the foreign object lodged?
in trachea
obstructing entire airway
What is a bronchopulmonary segment?
each segment works as discrete unit of lung consisting of a pulmonary artery, pulmonary vein and bronchi
they contain alveoli where gas exchange occurs
How can bronchopulmonary segments be important surgically?
each segment = discrete anatomical + functional unit
therefore individual segments can be resecting without affecting function of others
What is the difference in the layout of structures in the left and right hilum of the lung and why?
left = artery superior to bronchus
right = bronchus superior to artery
What vertebral level is the hyoid bone at and what does it look like from above?
C3
semi-circle
What vertebral level is the thyroid cartilage at and what does it look like from above?
C4/5
V-shaped
What vertebral level is the cricoid cartilage at and what does it look like from above?
C6
Complete circle
What vertebral level is the trachea at and what does it look like from above?
C6-T3
Semi-circle with straight membrane across back
Function of nasal cavity
warm, filter and humidify air
Name the 4 sinuses
maxillary
ethmoid
sphenoid
frontal
Lining of nasopharynx
respiratory epithelium
Lining of oropharynx
stratified squamous epithelium
Lining of laryngopharynx
stratified squamous epithelium
Where do the sinuses drain?
nasal cavity
What are the 3 areas of the pharynx?
nasopharynx
oropharynx
laryngopharynx
Innervation of mucosa of larynx and cricothyroid muscle?
superior laryngeal nerve
Innervation of intrinsic muscles of larynx except cricothyroid muscle?
recurrent laryngeal nerve
What substances pass through the nasopharynx, oropharynx and laryngopharynx?
nasopharynx = food + air
oropharynx = food + air
laryngopharynx = where foodway and airway separate, oesophagus = posterior, trachea = anterior
What is the only part of the airway that is a complete ring?
cricoid cartilage
Where does the eustachian tube open into and what is it’s function?
opens into middle ear
maintains atmospheric pressure in middle ear
what cartilage attaches posteriorly to the vocal cords?
arytenoid cartilage
