Human Respiratory System Anatomy

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Questions and Answers

Which of the following structures does the 2nd Intercostal nerve connect with?

Medial cutaneous nerve of the arm (correct)

Azygos vein

Phrenic nerve

Lateral cutaneous branch

What is the main function of the Azygos vein?

Supplies blood to the heart

Drains blood from the head and neck

Carries blood to the lungs

Connects the superior and inferior vena cava (correct)

What happens to the margins of the base of the lung during deep inspiration?

They disappear

They decline (correct)

They remain constant

They increase

What is the central tendon of the diaphragm?

A central aponeurosis that the peripheral muscular portion inserts into Signup and view all the answers

What is the name of the lower zone of the pleural cavity that the lung enlarges into during inspiration?

Costodiaphragmatic recess Signup and view all the answers

What are the three components of the muscular part of the diaphragm?

Vertebral, sternal, and costal Signup and view all the answers

What is the primary function of the phrenic nerves?

Motor innervation of the diaphragm Signup and view all the answers

What is the name of the part of the parietal pleura that extends into the root of the neck?

Cupola Signup and view all the answers

What is the function of the suprapleural membrane?

It covers the cervical pleura Signup and view all the answers

What is the sensory supply of the central part of the diaphragm?

Phrenic nerves Signup and view all the answers

Which artery rises above the subclavian artery?

Vertebral artery Signup and view all the answers

What is the relationship between the scalenus anterior muscle and the cervical pleura?

The muscle envelops the anterolateral part of the pleura Signup and view all the answers

What is the direction of the costocervical trunk?

It arcs towards the back Signup and view all the answers

What is the location of the first thoracic sympathetic ganglion in relation to the dome of the pleura?

Medial to the dome Signup and view all the answers

Which of these structures reinforce the cervical pleura?

Sibson fascia Signup and view all the answers

Where does the sternal line of pleural reflection occur?

Where the costal pleura meets the mediastinal pleura Signup and view all the answers

Which of these lines of pleural reflection is described as gradual and round?

Vertebral line Signup and view all the answers

Which of these structures is innervated by somatic afferent fibers?

Parietal pleura Signup and view all the answers

What is the main nerve innervating the diaphragmatic pleura?

Phrenic nerves Signup and view all the answers

What is the main nerve innervating the costal pleura?

Intercostal nerves Signup and view all the answers

Where does the visceral pleura become continuous with the parietal pleura?

At the hilum of the lung Signup and view all the answers

What is the relationship between the visceral pleura and the lung?

Firmly attached Signup and view all the answers

What is the inferior boundary of the Superior Mediastinum?

Transverse thoracic plane Signup and view all the answers

What is the main function of the thymus gland?

Production of white blood cells Signup and view all the answers

Where does the Superior Vena Cava enter the right atrium?

Level of the 3rd right costal cartilage Signup and view all the answers

Which of the following is NOT a branch of the aortic arch?

Right subclavian artery Signup and view all the answers

What is the Ligamentum arteriosum?

A fibrous remnant of the ductus arteriosus Signup and view all the answers

Which of the following nerves is NOT found in the Superior Mediastinum?

Facial nerve Signup and view all the answers

Which of the following is NOT a structure found in the Posterior Mediastinum?

Thymus gland Signup and view all the answers

What is the correct order of structures in the Superior Mediastinum, from anterior to posterior?

Thymus gland, Trachea, Great Vessels, Esophagus Signup and view all the answers

Where is the parietal pleura located?

Lines the chest wall and mediastinum Signup and view all the answers

What is the clinical significance of the pleural surface projection?

It guides the placement of central venous cannulas and abdominal surgery Signup and view all the answers

What is the location of the apex of the pleura relative to the clavicle?

2.5 cm above the medial third of the clavicle Signup and view all the answers

At what level does the pleura run toward the midline behind the angle of Louis?

Second costal cartilage Signup and view all the answers

Where does the right pleura continue downward?

Right side of the xiphisternal joint Signup and view all the answers

Which rib does the lower limit of the costal pleura cross in the midaxillary line?

Tenth rib Signup and view all the answers

What is the relationship between the surface markings of the lungs and the pleura?

The lung markings closely follow the pleural markings Signup and view all the answers

In quiet respiration, how much higher is the lower edge of the lung compared to the lower limit of the pleura?

5 cm Signup and view all the answers

Study Notes

Intercostal Nerve and Angina Pectoris

The 2nd intercostal nerve connects to the medial cutaneous nerve of the arm via the intercostobrachial nerve.
Pain from angina pectoris and myocardial infarction can be referred to the medial side of the arm, following this nerve pathway.
The upper six intercostal nerves innervate the skin, parietal pleura, and intercostal muscles within their respective spaces.

Azygos Vein

Connects the inferior vena cava (IVC) with the superior vena cava (SVC).
Originates in the abdomen from the IVC at the level of L2.
Enters the thorax through the aortic opening of the diaphragm on the right side of the thoracic duct and aorta.
Passes behind the right border of the esophagus and the root of the right lung in the posterior mediastinum.
Crosses above the root of the right lung in the superior mediastinum and enters the back of the SVC.

Respiratory Diaphragm

Separates the thoracic and abdominal cavities, consists of a peripheral muscular part and a central tendon.
The muscular part is derived from vertebral, sternal, and costal components.

Nerve Supply to the Diaphragm

Motor supply arises from the phrenic nerves (C3, C4, C5), primarily facilitating inspiration.
Sensory innervation to the diaphragm's periphery comes from lower intercostal nerves, while central sensory information is supplied by phrenic nerves.

Pleural Reflection Lines

Abrupt lines mark where parietal pleura shifts direction within the pleural cavity.
Sternal line: where costal pleura meets mediastinal pleura anteriorly.
Costal line: where costal pleura joins diaphragmatic pleura inferiorly.
Vertebral line: a gradual transition point for costal pleura connecting with mediastinal pleura posteriorly.

Innervation of Parietal Pleura

Somatic afferent fibers provide innervation to the parietal pleura.
Costal pleura innervated by intercostal nerves, causing pain sensation related to the thoracic wall.
Diaphragmatic and mediastinal pleura mainly receive sensory input from phrenic nerves, with referred pain to C3, C4, C5 dermatomes.

Visceral Pleura

Continuous with parietal pleura at the lung hilum, firmly adheres to lung surfaces.
The costodiaphragmatic recess is the space into which the lung expands during inspiration, found at the base.

Mediastinum Divisions

Divided into superior and inferior mediastinum by the transverse thoracic plane.
Superior mediastinum includes thymus, great vessels, vagus and phrenic nerves, trachea, esophagus, thoracic duct, and pleura.
Inferior mediastinum is subdivided into anterior (thymus remnants), middle (heart and great vessels), and posterior (esophagus, great vessels, vagus nerves, sympathetic trunks).

Superior Mediastinum Contents

Thymus gland located behind the manubrium, involutes post-puberty.
Great vessels include Brachiocephalic veins and superior vena cava.
Arch of the aorta spans from behind the 2nd right sternoclavicular joint to the 2nd left sternoclavicular joint; branches include Brachiocephalic trunk, left common carotid artery, and left subclavian artery.

Thoracic Inlet and Pleura Position

The thoracic inlet is defined by the first rib, with the pleural apex lying 2.5 cm above the medial end of the clavicle and more at the apex.
The pleura descends laterally towards the midline, with crucial surface projections detailed for clinical significance to avoid pneumothorax during procedures.

Lung Surface Markings

Lung edges are typically above pleural edges due to fluid separation, with the excursion during deep respiration reaching 7.5 cm.
The inferior lung border crosses the sixth rib at the midclavicular line, eighth rib at the midaxillary line, and tenth rib near the erector spinae.

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Description

Test your knowledge of the human respiratory system, including nerves, veins, lungs, and diaphragm anatomy.