Thorax IV: Superior and Posterior Mediastinum

A set of flashcards to help students review the anatomy and physiology of the thorax, specifically the superior and posterior mediastinum, as covered in MSBS 611 Anatomy.

What is the central compartment of the thoracic cavity known as?

Mediastinum.

What structures does the mediastinum contain?

All thoracic viscera and structures except the lungs.

What are the anatomical boundaries of the mediastinum?

Extends from the superior thoracic aperture to the diaphragm, anteriorly by the sternum, and posteriorly by the thoracic vertebrae.

How does the structure of the mediastinum relate to its mobility?

It is composed mainly of hollow structures which allow for high mobility.

What divides the mediastinum into subdivisions?

Transverse thoracic plane.

Name the subdivisions of the mediastinum.

Superior, anterior, middle, and posterior mediastinum.

Where is the superior mediastinum located?

Between the sternal angle and T4/T5 vertebrae.

What is located in the middle mediastinum?

The pericardium, heart, and roots of great vessels.

What is the main function of the esophagus within the thoracic cavity?

To transport food from the throat to the stomach.

How does the vagus nerve function in the mediastinum?

It provides parasympathetic innervation to various thoracic organs.

What are the major blood vessels located in the mediastinum?

Aorta, superior vena cava, and esophagus.

What is the fibrous pericardium?

The tough outer layer of the pericardium that stabilizes the heart.

What connects the fibrous pericardium to the sternum?

Sternopericardial ligaments.

What lies within the pericardial cavity?

A thin film of fluid that facilitates heart movement.

What is the main artery supplying the pericardium?

Pericardiacophrenic artery.

What is the significance of the pericardiacophrenic ligament?

It connects the fibrous pericardium to the diaphragm.

What does the oblique pericardial sinus surround?

Reflections of the serous pericardium around the venous vessels.

What are the two main sources of venous drainage for the pericardium?

Pericardiacophrenic veins and tributaries of the brachiocephalic veins.

What is the primary sensory nerve supplying the pericardium?

Phrenic nerve.

Where do the phrenic nerves originate?

C3 to C5 spinal levels.

What anatomical landmark does the pericardial cavity represent a potential space for?

Between the parietal and visceral layers of the serous pericardium.

What type of pain is associated with irritation of the fibrous pericardium?

Somatic pain referred to the dermatomes of the body wall.

What anatomical structures does the pericardium protect?

The heart within the thoracic cavity.

What happens to connective tissue in the mediastinum with age?

It becomes more fibrous and reduces mediastinal mobility.

How does the heart's position relate to the median plane?

About two-thirds of the heart lies to the left of the median plane.

What clinical significance does the transverse pericardial sinus have during surgery?

It allows access to major vessels for procedures like coronary artery bypass grafting.

Where is the oblique pericardial sinus located?

Posterior to the base of the heart.

What does the transverse pericardial sinus provide access to?

Major vessels like the ascending aorta and pulmonary trunk.

What is the role of the mesothelium in the pericardium?

Lines the fibrous pericardium and covers the heart surface.

What is one effect of rapid lung growth on the mediastinum?

It can lead to the separation of pleuropericardial membranes.

How does the position of the aorta change when lying supine?

The arch of the aorta lies superior to the transverse thoracic plane.

What is the position of the tracheal bifurcation when standing?

It is positioned inferior to the transverse thoracic plane.

What effect does the diaphragm's position have on the mediastinum?

It impacts the location of thoracic structures during breathing.

What surrounds the ventricles of the heart as part of its anatomy?

The visceral layer of the serous pericardium.

What does the central tendon of the diaphragm connect to?

The fibrous pericardium.

What is the anatomical relevance of the sympathetic trunk?

It plays a role in autonomic regulation in the mediastinum.

What potential space exists between the heart and pericardial sac?

Pericardial cavity.

How does the serous pericardium relate to the heart?

It reduces friction as the heart beats.

What is unique about the structure of the fibrous pericardium?

It protects against sudden overfilling due to its unyielding structure.

What connects the phrenic nerves to the pericardium?

They run between the heart and lungs.

What type of tissue surrounds the mediastinum?

Connective tissue, blood, and lymphatic vessels.

What lymphatics are associated with the mediastinum?

Lymph nodes and lymph vessels.

How can the heart's position be visually approximated?

By turning the head 45° to the left without moving the shoulders.

What is the course of the esophagus in the mediastinum?

It runs behind the trachea and heart, terminating in the stomach.

What anatomical feature helps to stabilize the heart?

Fibrous pericardium.

Name the primary organs found in the mediastinum.

Heart, aorta, superior vena cava, esophagus.

What is significant about the anatomic orientation of the heart?

It is not centered but tilted to the left.

What does the term 'anterior mediastinum' refer to?

The area in front of the pericardium.

What is the role of connective tissue in the mediastinum?

It serves as a supportive framework for vessels and nerves.

What happens to mediastinal contents during respiration?

They shift slightly with diaphragmatic movements.

What does the middle mediastinum include?

The pericardium and elements within it.

What ligaments support the pericardium?

Sternopericardial ligaments.

Which vessels are accompanied by the pericardiacophrenic artery?

Phrenic nerve.

What anatomical change occurs with aging in the mediastinum?

Increased fibrous tissue and decreased mobility.

What are pericardial sinuses?

Recesses formed by reflections of serous pericardium.

Where does the oblique pericardial sinus lie in relation to the heart?

Posterior to the base of the heart.

What is a potential complication during thoracic surgery concerning the mediastinum?

Damage to the nerves or vessels can occur during manipulation.

What anatomical structure does the pericardial cavity separate?

The heart and the layers of the pericardium.

How does the fibrous pericardium assist in heart function?

Prevents over-expansion and anchors the heart.

What anatomical change occurs to the position of structures in the mediastinum when transitioning from supine to upright?

Shifts in relation to the transverse thoracic plane.

What vessels are found in the posterior mediastinum?

Descending aorta and associated tributaries.

How does the position of the diaphragm influence thoracic structures?

It alters the alignment and position of the heart and great vessels.

What is the clinical importance of massive fluid accumulation in the pericardial cavity?

It may lead to cardiac tamponade.

What distinguishes the visceral layer of serous pericardium from the parietal layer?

The visceral layer directly covers the heart.

How do the pericardial sinuses develop?

From reflections of serous pericardium around vessels.

What anatomical relationship does the phrenic nerve maintain?

It runs alongside the pericardiacophrenic vessels.

What is the impact of excessive mobility of the mediastinum?

It can enhance respiratory capacity.

What type of surgical approach utilizes the transverse pericardial sinus?

Cardiac surgery to control blood flow.

What structures can be accessed through the transverse pericardial sinus?

Ascending aorta and pulmonary trunk.

Why is the pericardial cavity clinically significant?

It allows for the examination of pericardial conditions.

What changes occur to the orientation of the heart with changes in body position?

The heart's tilt can affect blood flow dynamics.

What kind of pain might indicate issues with the pericardium?

Pain referred to C3 to C5 dermatomes.

What does the phrenic nerve primarily carry?

Sensory fibers related to the diaphragm and pericardium.

What anatomical feature stabilizes the relationship between the heart and diaphragm?

The pericardiacophrenic ligament.

What happens to mediastinal structures with age?

They may lose flexibility and become more fibrous.

What is the clinical significance of the oblique pericardial sinus?

Allows for access to surrounding great vessels.