Thoracic Wall & Pleura Flashcards
What does the thoracic skeleton consist of?
Thoracic skeleton consists of:
- 12 pairs of ribs and costal cartilages
- 12 thoracic vertebra and IVD
- Sternum
How many ribs are there?
How can they be classified?
Which are typical and which are atypical?
Ribs
Ribs classified into:
1) True Ribs
2) False ribs
3) Floating ribs.
Another classification:
1) Typical ribs – 3- 9 th ribs
2) Atypical ribs – 1, 2, 10, 11, 12
What is the cervical rib?
Clinical significance?
- A cervical rib = a rib arising from the anterior tubercle of the transverse process of the 7th cervical vertebra.
- The importance of a cervical rib is that it can cause pressure on the lower trunk of the brachial plexus in some patients, producing pain down the medial side of the forearm and hand and wasting of the small muscles of the hand.
- It can also exert pressure on the overlying subclavian artery and interfere with the circulation of the upper limb.
What is flail chest?
Flail Chest
- In severe crush injuries, a number of ribs may break.
- This causes flail chest.
- The flail segment is sucked in during inspiration and driven out during expiration, producing paradoxical and ineffective respiratory movements.
A flail chest is a chest in which sections of broken ribs are isolated from, and interfering with, normal chest movements. That means the chest cannot expand properly and cannot properly draw air into the lungs. This is why stabilization after blunt trauma is important.
What are the intercostal spaces?
Which 3 muscles run here?
In what order do the intercostal vein, arteries and nerves run?
Intercostal spaces
- The spaces between the ribs contain three muscles of respiration: the external intercostal, the internal intercostal, and the innermost intercostal muscle.
- The intercostal nerves and blood vessels run between the intermediate and deepest layers of muscles.
- They are arranged in the following order from above downward: intercostal vein, intercostal artery, and intercostal nerve (i.e., VAN).
What are the intercostal spaces?
Which 3 muscles run here?
In what order do the intercostal vein, arteries and nerves run?
Intercostal spaces
- The spaces between the ribs contain three muscles of respiration: the external intercostal, the internal intercostal, and the innermost intercostal muscle.
- The intercostal nerves and blood vessels run between the intermediate and deepest layers of muscles.
- They are arranged in the following order from above downward: intercostal vein, intercostal artery, and intercostal nerve (i.e., VAN).
Which nerves supply the intercostal muscles?
The intercostal muscles are supplied by the corresponding intercostal nerves.
The intercostal nerves are the anterior rami of the first 11 thoracic spinal nerves. The anterior ramus of the 12th thoracic nerve lies in the abdomen and runs forward in the abdominal wall as the subcostal nerve.
Intercostal nerve block
The needle is directed toward the rib near the lower border.
How many arteries does each intercostal space have?
What is the origin of the posterior intercostal arteries?
What is the origin of the anterior intercostal arteries?
Each intercostal space contains a large single posterior intercostal artery and two small anterior intercostal arteries.
The posterior intercostal arteries of the first two spaces are branches from the superior intercostal artery, a branch of the costocervical trunk of the subclavian artery. The posterior intercostal arteries of the lower nine spaces are branches of the descending thoracic aorta.
The anterior intercostal arteries of the first six spaces are branches of the internal thoracic artery, which arises from the first part of the subclavian artery. The anterior intercostal arteries of the lower spaces are branches of the musculophrenic artery, one of the terminal branches of the internal thoracic artery.
Where do the intercostal veins drain into?
The corresponding posterior intercostal veins drain backward into the azygos or hemiazygos veins, and the anterior intercostal veins drain forward into the internal thoracic and the musculophrenic veins.
How does the chest cavity communicate with the root of the neck?
Boundaries?
Clinical significance?
- The chest cavity communicates with the root of the neck through an opening called the thoracic outlet.
- Important vessels and nerves emerge from the thorax here to enter the neck and upper limbs.
- The opening is bounded posteriorly by the 1st thoracic vertebra, laterally by the medial borders of the 1st ribs and their costal cartilages, and anteriorly by the superior border of the manubrium sterni.
- Thoracic outlet syndrome → symptoms are caused by pressure on the lower trunk of the plexus producing pain down the medial side of the forearm and hand and wasting of the small muscles of the hand. Pressure on the blood vessels may compromise the circulation of the upper limb.
What are the pleura? 2 layers?
What does the parietal pleura adhere to? (3)
4 parts of the parietal pleura?
Pleura
- Each pulmonary cavity is lined by a pleural membrane (pleura) that also reflects onto and covers the external surface of the lungs occupying the cavities.
- The visceral pleura (pulmonary pleura) closely covers the lung.
- The parietal pleura lines the pulmonary cavities, thereby adhering to the thoracic wall, mediastinum, and diaphragm.
- The parietal pleura consists of four parts—costal, mediastinal, and diaphragmatic and the cervical pleura.
- The pleural cavity between the two layers of the pleural sac is empty, except for a lubricating film of pleural fluid. The pleural fluid prevents the lungs from collapse and causes the lungs to expand when the thorax expands for inhalation.
What are the following Lines of orientation:
- Midsternal line
- Midclavicular line
- Anterior axillary line
- Posterior axillary line
- Midaxillary line Scapular line
Where does the anterior border of the RIGHT pleura run?
Where does the anterior border of the LEFT pleura run?
The anterior border of the right pleura runs down behind the sternoclavicular joint, almost reaching the mid- line behind the sternal angle.
It continues downward until it reaches the xiphisternal joint.
The anterior border of the left pleura has a similar course, but at the level of the fourth costal cartilage it deviates laterally and extends to the lateral margin of the sternum to form the cardiac notch.
Where do the lower borders of the pleura run?
The lower border of the pleura on both sides follows a curved line, which crosses the 8th rib in the midclavicular line and the 10th rib in the midaxillary line, and reaches the 12th rib adjacent to the vertebral column.
The lower margins of the lungs cross the 6th, 8th, and 10th ribs at the midclavicular lines, the midaxillary lines, and the sides of the vertebral column, respectively The lower margins of the pleura cross, at the same points, the 8th, 10th, and 12th ribs, respectively.
What are the 2 recesses of the pleura?
Recess
- Because the lungs do not completely fill the pulmonary cavities, and because of the
protrusion of the diaphragm and underlying abdominal viscera into the inferior thoracic aperture, the costodiaphragmatic recess is
formed. - Extrapulmonary fluids accumulate in this space when the trunk is erect.
