Respiratory Anatomy

Question 0

State the features of a typical rib and thoracic vertebrae

Answer 0

Ribs:
Two articular facets separated by crest, head, neck, articular surface, shaft, costal groove on inferior surface
Thoracic vertebrae:
Transverse processes

Question 1

Describe the structure of the bony thorax

Answer 1

12 thoracic vertebrae, 12 ribs, sternum
Superior thoracic aperture, clavicular notch, jugular notch, manubrium sterni, sternal angle, body, costal cartilage, xiphoid process, costal margin, inferior thoracic aperture
Ribs 1-7 - connected to sternum by costal cartilage
Ribs 8-10 - connected to the costal cartilage above
Ribs 11-12 - floating ribs, end free in abdominal muscles

Question 2

Describe how ribs 1+2 and 11+12 are different to typical ribs

Answer 2

Rib 1 - shortest, broadest, most curved head, has a single facet
Rib 2 - poorly marked costal groove, roughened area on upper surface (serratus anterior)
Rib 11+12 - floating, have a single facet on head, no tubercle, tapering at anterior end

Question 3

Describe the relations and arrangement of muscles in the thoracic wall and diaphragm, and state briefly their functions and nerve supply

Answer 3

Intercostal muscles (end where costal cartilage starts):
External intercostal - down, anterior
Internal intercostal - down, posterior
Innermost 
Function - respiration
Nerve supply - intercostal nerves

Question 4

Describe the distribution of the intercostal nerves, arteries and veins

Answer 4

In costal groove on inferior surface of rib

Question 5

Describe the pleural cavity and pleura, and stare the lines of pleural reflections

Answer 5

Parietal pleura, visceral pleura 
Pleural cavity (containing pleural fluid)

Question 6

Describe the structure and arrangement of airways and blood vessels in the lungs

Answer 6

Trachea –> bronchi –> bronchioles –> alveolar ducts –> alveoli
Arteries - thoracic aorta –> posterior intercostal artery, subclavian artery –> internal thoracic artery –> anterior intercostal artery
Veins - hemiazygos vein –> azygos vein –> SVC

Question 7

Describe the muscles in respiration

Answer 7

Inspiration - external intercostal, diaphragm, sternocleidomastoid, scalenes
Forced expiration - internal intercostal, anterior abdominals (rectus abdominis)

Question 8

Describe the anatomy of the diaphragm and relevant openings

Answer 8

Right crus --> L4
Left crus --> L3
Openings - T8 (vena cava), T10 (oesophagus) T12 (aorta) 
Phrenic nerve 
Arcuate ligaments

Question 9

Describe the mediastina and their contents

Answer 9

Central compartment in thoracic cavity
Middle - heart enclosed in pericardium, ascending aorta, bifurcation of trachea, pulmonary vessels, phrenic nerve
Anterior - loose areolar CT, lymphatic vessels, lymph nodes, thymus
Superior - aortic arch, brachiocephalic, vagus nerve, cardiac nerve, phrenic nerve, left recurrent laryngeal nerve, trachea, oesophagus
Posterior - descending aorta, (hemi)azygos vein, vagus nerve, oesophagus
Inferior

Question 10

Describe in general terms the structure of the pulmonary circulation and the characteristics that distinguish it from the systemic circulation

Answer 10

IVC/SVC –> RA –> RV –> pulmonary arteries –> lungs –> pulmonary veins
Pulmonary veins –> LA –> LV –> aorta
Pulmonary circulation - lower pressure

Question 11

Define the terms ‘Functional Residual Capacity’, ‘Residual Volume’, ‘Vital Capacity’ and ‘Inspiratory Capacity’

Answer 11

Functional residual capacity - volume of air in lungs at resting expiratory level
Residual volume - volume left in lungs at maximal expiration
Vital capacity - maximum inspiration –> maximum expiration
Inspiratory capacity - biggest breath that can be taken

Question 12

Define the terms ‘Serial Dead Space’ and ‘Physiological Dead Space’ and state in general terms how these variables are measured

Answer 12

Serial dead space - parts of airway that do not participate in gas exchange e.g. nasal cavity, nasopharynx, oropharynx, laryngopharynx, trachea, bronchi etc.
Physiological dead space - parts of the lung that do not support gas exchange e.g. dead/damaged alveoli, alveoli with poor perfusion

Question 13

Calculate alveolar ventilation rate when given the pulmonary ventilation rate, dead space volume and respiratory rate

Answer 13

AVR = pulmonary ventilation rate - dead space ventilation rate
Pulmonary ventilation rate = tidal volume x respiratory rate
Dead space ventilation rate = dead space ventilation x respiratory rate