Anatomy - The Thoracic cage Flashcards
Describe the external intercostal muscle?
- Only attached to the ribs 1-11 (not over costal cartilages)
- Runs down and medially across ribs (hands in pockets)
- form a sheet at the most anterior end of the ribs around the articulation with vertebrae at the back
- Originate at the lower border of the rib, inserting into the superior border of the rib below
Describe internal intercostal muscle?
- Separated from external intercostal muscle by a plural membrane
- run 90 degrees to external intercostal muscle (hands on chest)
- Originates from the lateral edge of the costal groove
- inserts into the superior surface of the rib below.
What membrane connects the cartilages between articulating rips?
anterior coastal membrane
What direction does the Oblique muscle and membrane run?
Same as external intercostal muscle (hands in pocket)
How are the intercostal muscles innervated?
Intercostal nerves T1-T11
What arteries supply the abdominal wall and diaphragm?
internal mammary arteries (aka internal thoracic arteries)
What is the difference between the visceral pleura and parietal pleura?
- visceral pleura is directly in contact with the lungs
- parietal pleura is directly on the chest wall, internal surfaces of the thoracic cavity
What is contained within the pleural cavity and what is its function?
- Serous fluid
- lubricates visceral layers
- creates tension between visceral layers so when thorax expands so do the lungs
Describe the pleural recesses?
- Where the pleural cavity is not completely filled by the lungs, parietal pleura touches
- costodiaphragmatic
- costomediastinal
- locations of pleural effusion
Describe the neurovascular supply of the 2 pleurae?
- Parietal pleura - sensitive to pain, pressure and temperature via phrenic and intercostal nerves, supplied by Intercostal arteries
- Visceral pleura - only detects stretch, autonomous innervation from pulmonary plexus, supplied by bronchial arteries
Name the connection between the lung and mediastinum? What does it contain?
- Called the hilum
- 1 pulmonary artery
- 2 pulmonary veins
- bronchus
- lymphatic vessels
- branches of vagus and sympathetic nerves
What can make impressions on the left and right lungs?
- Major mediastinal structures
- shows close contact ie spreading disease
Describe the diaphragm? How is it innervated?
- non-contracting central tendon
- peripheral muscle fibres
- innervated by phrenic nerves arises from C3, 4 and 5
What are the 2 effects of the diaphragm contracting?
- Glottis is open and air is drawn into the lungs
- blood is drawn from the inferior vena cava into the right atrium
What is a V/Q scan?
- V - ventilation, breath in radioactive gas alveoli usage is visualized
- Q - perfusion, technetium is injected into the blood, visualizes blockages of pulmonary arteries
What is an intercostal recession? What is it’s clinical relevance?
- intercostal spaces stuck in during inspiration
- sign of advanced respiratory distress, especially in the first 6th months of life
What is grafted to the left anterior descending coronary artery when it is narrowed?
left internal mammary artery
What is the function of the lungs?
Oxygenates blood by bringing inspired air into contact with O2 poor blood in the pulmonary capillaries.
What does the internal thoracic artery branch into?
- Musculophrenic - supplies the diaphragm.
- Superior epigastric arteries - supplies the front of the abdomen.
What is the pleural cavity?
A potential space between the visceral and parietal pleura.
Name 2 functions of the serous fluid within the pleural cavity?
- Lubricates the pleurae.
- Creates a surface tension helping the lungs to expand on inspiration.
What branch does the right main bronchus give off outside of the right lung?
Superior lobar bronchus.
What other smaller vessels are found at the hilum of the lung?
- Bronchial arteries. 2. Pulmonary plexus of autonomic nerves. 3. Lymph nodes.
Which lung are inhaled foreign bodies most likely to be found in and why?
The right lung. The right main bronchus is shorter and more vertical.
How many lobes does the right lung have and what are they called?
3 lobes. Superior, middle and inferior.
How many lobes does the left lung have and what are they called?
2 lobes. Superior and Inferior.
What is the fissure in the left lung called?
Oblique (lies along 6th rib).
What are the fissures in the right lung called?
Horizontal (extends from mid-axiallry line anteriorly along the 4th rib) and Oblique (lies along 6th rib).
Name the 3 surfaces of the lungs.
- Costal
- Mediastinal
- Diaphragmatic
Name the 3 borders of the lungs.
- Anterior
- Posterior
- Inferior
Describe the innervation of the lungs?
- Parasympathetic innervation derived from vagus nerve
- Sympathetic innervation derived from sympathetic trunks
- Visceral afferent - conducts pain impulses to sensory ganglion
What is the action of parasympathetic innervation in the lung?
Bronchoconstriction and vasodilation of pulmonary vessels.
What is the action of sympathetic innervation in the lung?
Bronchodilation and vasoconstriction of vessels that are poorly ventilated.
What is the surface marking for the apex of the lung?
2 finger breadths (3cm) above the medial clavicle in the neck.
What are the surface markings for the lower border of the lung?
6th rib anteriorly, 8th rib in the mid-axillary line and 10th rib posteriorly.
What are the surface markings for the lower border or the pleural cavity?
8th rib anteriorly, 10th rib in the mid-axillary line and 12th rib posteriorly.
