Thoracic wall, pleura, diaphragm

Question 1

Describe features of the sternum and their positioning

Answer 1

manubrium, body and xiphoid process

Jugular notch is important part of the manubrium. T3

The joint between the manubrium and body (manubriosternal joint/sternal angle) marks the level of the intervertebral disc between thoracic vertebrae 4 and 5, which is an important landmark for the boundary between the superior and inferior mediastinum.

Xiphisternal joint is a cartilaginous symphysis joint and lies at the level of T9/T10. ossifies about the 40th year

Coastal margin can be palpated by the coastal cartilage. Subcoastal angle is where coastal margins meet

Question 2

What are the two thoracic apertures

Answer 2

Superior and inferior thoracic apertures

Question 3

Describe the Superior Thoracic Aperture

Answer 3

formed from the superior borders of the first ribs and their costal cartilages, the jugular notch of the sternum and T1 vertebra.

The apices of the lungs extend through this aperture and the trachea, oesophagus, brachiocepahlic veins, brachiocephalic trunk, left common carotid and left subclavian arteries traverse the superior thoracic aperture.

Question 4

Describe the Inferior Thoracic Aperture

Answer 4

bounded by the costal margins, xiphisternum, 12th rib and T12 vertebra.

• Structures traverse the inferior thoracic aperture only by travelling through the apertures of the thoracic diaphragm as this diaphragm attaches to the boundaries of the inferior thoracic aperture and closes it.
• These structures include the descending aorta, vagus nerves, inferior vena cava and oesophagus.

Question 5

Scapula positioning

Answer 5

Scapular spine (length) is in T3. Inferior angle is at T7

Question 6

Internal Thoracic Arteries

Answer 6

Origin - collateral branches of subclavian arteries

Course - travels inferiorly, lateral to the sternum and supplies blood to anterior intercostal arteries

Question 7

Anterior Intercostal Arteries

Answer 7

Origin - collateral branches of internal thoracic arteries
Course - travels through and supplies blood to the anterior intercostal spaces
Supply tissue within IC spaces and overlying skin
Forms anastomoses with Posterior IA

Question 8

Posterior Intercostal Arteries

Answer 8

Origin - collateral branches of thoracic aorta
Course - travels through and supplies blood to the posterior intercostal spaces
Supply tissue within IC spaces and overlying skin
Right arteries are a bit longer

Question 9

Azygos Vein

Answer 9

Ascends on the right side of the vertebral bodies through the thoracic cavity to drain into the superior vena cava. Receives blood from the right posterior intercostal veins (drains posterior and lateral thoracic wall).

Question 10

Hemiazygos Vein

Answer 10

Ascends on the left side of the vertebral bodies and passes anteriorly across the vertebral bodies to flow into the azygos vein on the right side. Receives blood from the left inferior posterior intercostal veins (drains posterior and lateral thoracic wall).

Question 11

Accessory Hemiazygos Vein

Answer 11

Descends on the left side of the vertebral bodies and also passes anteriorly across the vertebral bodies to flow into the azygos vein on the right side. Receives blood from the left superior posterior intercostal veins (drains posterior and lateral thoracic wall).

Question 12

Location and features of female breast

Answer 12

Body
Base of breast (circular portion) and Apex (areola)

Axillary tail
Extension of the base towards and into the axilla, formed by glandular tissue

Retromammary space
Loose CT plane between breast and deep pectoral fascia. Fatty tissue allows movement

Breast is connected to dermis by suspensory ligaments

Question 13

Internal features of breast

Answer 13

Each lobe:
- Drained by one major lactiferous duct
- Contains numerous lobules
- Contains branches and sub-branches of a major lactiferous duct
Separated by and contains varying amounts of adipose tissue and general CT

Question 14

Domes of the Thoracic Diaphragm

Answer 14

The thoracic diaphragm consists of a right and left dome. The summit of the right dome is located at the 4th intercostal space and thoracic vertebra 9. The summit of the left dome is located at the 5th intercostal space and thoracic vertebra 10.

Question 15

central tendon

Answer 15

The central tendon of the thoracic diaphragm is a trifoliate (3 leaves/parts) aponeurosis into which all of the muscle fibres of the thoracic diaphragm insert. Attached to the pericardium of the heart.

Question 16

The left and right crura

Answer 16

The left and right crura of the thoracic diaphragm are elongated muscle fibres that are located on either side of the aorta.

Question 17

3 major apertures of the thoracic diaphragm

Answer 17

Caval foramen: located in the central tendon at T8/9; the inferior vena cava and branches of the phrenic nerve traverse this foramen.

Oesophageal hiatus: located in the right crus of the thoracic diaphragm at T10; the oesophagus and vagus nerves traverse this passageway.

Aortic hiatus: located posterior to the crura of the thoracic diaphragm at T12; the descending aorta, thoracic duct, inferior intercostal lymphatic trunks and the azygos and hemiazygos veins traverse this passageway.

Question 18

Innervation of Thoracic Diaphragm

Answer 18

1. phrenic nerves

2. intercoastal nerves

Question 19

Cardiophrenic recess positioning

Answer 19

The cardiophrenic recess lies between the pericardial sac and the thoracic diaphragm

Question 20

Costophrenic recesses

Answer 20

the costophrenic recess lies between the thoracic cage and the thoracic diaphragm.
The costophrenic recess can be described in three parts: anterior, lateral and posterior. The costophrenic recesses are typically not filled with lung tissue at rest and only fill with lung tissue during forced inspiration. They are therefore the ideal location for collecting pleural fluid for diagnostic purposes.

Question 21

Lingula of superior lobe of left lung

Answer 21

Lingula meaning ‘tongue’ is the most anteroinferior part of the superior lobe of the left lung which elongates around the heart inferiorly.

Question 22

Cardiac notch of superior lobe of left lung

Answer 22

Indent in anteromedial border of the superior lobe of the left lung due to the position of the heart moreso to the left side of the thoracic cavity.

Question 23

Blood supply to the lungs

Answer 23

The bronchial arteries supply oxygenated blood to the bronchi, walls of large vessels and visceral pleura. The bronchial arteries originate as collateral branches of the thoracic aorta

Question 24

Hilum of lung

Answer 24

The root of the lung consists of all of the structures entering and exiting from the hilum. All structures are envoloped in visceral pleura, called the pleural sleeve.