Thorax - Lecture 1 Flashcards
What structures does the thoracic wall protect?
- lungs
- heart
- great vessels
- liver
- spleen
what are the skeletal components of the thoracic wall?
- 12 thoracic vertebrae
- 12 pairs of ribs
- sternum
What are the parts of the sternum?
- manubrium
- body
- xiphoid process
what important structure on the manubrium of the sternum can you palpate?
jugular notch
What is the first rib you can palpate?
cartilage of the 2nd rib
What is the importance of the Angle of Louis?
It is a landmark to find the 2nd rib
what are 2 joints found in the the sternum?
- manubriosternal joint
2. Xiphisternal joint
what ribs are true ribs?
1st-7th
what ribs are floating ribs?
11th-12th
what ribs are false ribs?
8-10th
True (vertebrosternal) ribs
They attach directly to the sternum through their own costal cartilages
false (vertebrochondral) ribs
Their cartilages are connected to the cartilage of the rub above them; thus their connection with the sternum is indirect
Floating (vertebral, free) ribs
The rudimentary cartilages of these ribs do not connect even indirectly with the sternum; instead they end in the posterior abdominal musculature
what ribs are considered “typical ribs”
3rd - 9th
Which ribs are atypical ribs?
1, 2, 10-12th
What kind of joints connect the ribs to the vertebrae?
synovial joints
What is the purpose of the costal groove?
to protect intercostal vessels and nerves (VAN)
What does elevation of the lower ribs during inspiration do?
increases transverse diameter of thoracic cavity
What does elevation of the sternum do?
increases A-P dimension of thoracic cavity
The muscles of the thoracic wall are innervated by what nerve?
intercostal nerves
the scalene muscles are innervated by?
branches of the cervical plexus
what muscles are used during inspiration?
- scalenus muscles
2. external intercostal muscles
what muscles are used during expiration?
- internal intercostal muscles
- innermost intercostal muscles
- transverse thoracic muscle
- subcostal muscles
what action does the scalenus and external intercostal muscles perform?
they elevate the ribs during inspiration
what action do the muscles of expiration perform?
depression of ribs during expiration
what does the diaphragm separate?
separates the thoracic cavity from abdominal region
Which side of the diaphragm is higher? Why?
the right side because the liver is directly underneath . It is on the level of T8
What level of the diaphragm is the left side on?
T9
What are the 3 major openings in the diaphragm?
- vena caval aperture
- aortic aperture
- esophageal aperture
what are some examples of actions that the diaphragm take part in?
- coughing
- forced defecation
- weight lifting
- principle muscle of respiration
what nerve innervates the diaphragm?
phrenic nerve
where is the phrenic nerve derived from?
C3, C4, C5 - the cervical plexus because the diaphragm develops in the neck and travels downward to the diaphragm
what arteries are the posterior and anterior intercostal arteries derived from?
posterior intercostal artery –> the thoracic aorta
the subclavian artery
–> anterior intercostal arteries
Where are the major blood vessels found in relation to the ribs?
they are found on the underside of the rib.
what important vein does the azygos vein merge with?
the superior vena cava
the subcostal nerve comes from the ventral ramus of what vertebrae?
ventral rams of T12
what does the subcostal nerve innervate?
antero-lateral abdominal region
thoracoabdominal nerves
T7-T12
which nerves give rise to the intercostobrachial nerves ?
2nd and 3rd
what is found in the 11 intercostal spaces?
- intercostal muscles
- blood vessels
- nerves
where is the endothoracic fascia attached?
to ribs and muscles
where is the parietal pleura attached?
to endothoracic fascia
visceral pleura
attached to lung surface
parietal pleura
attached to the inner surface of the chest wall
what are the 2 nerves supplies that innervate the parietal pleura?
- intercostal nerves - costal pleura
2. phrenic nerve - mediastinal and diaphragmatic pleura
how many lobes does the right lung have?
3
how many lobes does the left lung have?
2
which fascia is attached to the ribs and muscles?
Endothoracic fascia
true or false, the parietal pleura is attached to endothoracic fascia
TRUE
serous fluid
A thin film that separates visceral and parietal pleura and reduces friction during breathing
name the different parts of the parietal pleura
- cervical pleura
- mediastinal pleura
- costal pleura
- diaphragmatic pleura
what are the components of the hilum?
- pulmonary artery
- pulmonary veins
- bronchus
- autonomous nerves
- lymph nodes
- bronchial arteries
- bronchial veins
- lymphatic vessels
In which bonchus does aspiration of foreign bodies occur? Why?
right; because it is not angled and is very direct
how many brochopulmonary segments does the right lung have?
10
how many brochopulmonary segments does the left lung have ?
9
which lung lobes drain into the right lymphatic duct?
The 3 lobes of the right lung and the lower lobe of the left lung.
What lung lobes drain into the left lymphatic (thoracic) duct?
only the upper lobe of the left lung
What lymph nodes drain the lungs, heart and mediastinal organs?
- tracheobronchial
2. retro and partracheal lymph nodes
What is the mediastinum?
space between the pleural cavities
what are the major organs of the mediastinum?
- trachea
- esophagus
- lymph vessels and nodes
- thymus
- great vessels
- heart
- nerves
What arteries make up the aortic arch?
- brachiocephalic trunk
- left common carotid artery
- left subclavian artery
Where does the phrenic nerve originate?
cervical plexus (C3-C5)
what is the sensory innervation of the phrenic nerve?
- pericardium
- parietal pleura - mediastinal, diaphragmatic
- parietal peritoneum - underside of diaphragm
in relation to the anterior scalenus muscle, where does the phrenic nerve run?
ventral to the anterior scalenus muscle. also descends anterior to the roots of the lungs and between the fibrous pericardium and the mediastinal pleura
what is the recurrent laryngeal nerve?
It is a branch of the vagus nerve that provides motor innervation to most of the muscles of the larynx. Also provides sensory innervation to the inferior larynx and courses lateral to the trachea
why does lung cancer cause hoarseness in the voice?
results from invasion of the recurrent laryngeal nerve
where does the thoracic duct drain into?
the left jugular-subclavian junction
where does 3/4 of the body drain venous blood into?
the thoracic duct