Anatomy of Heart and Pericardium

Study Notes

Fibrous Pericardium

Related to the corresponding right and left lungs, pleura, and phrenic nerves
Functions:
- Maintains the central position of the heart within the chest
- Prevents over-distension of the heart

Anterior Surface of Fibrous Pericardium

Separated from the thoracic wall by the pleural membranes and the anterior edges of the lungs
Bare area of pericardium:
- Located at the cardiac notch, behind the lower part of the left half of the body of the sternum and the sternal ends of the left 4th to 6th costal cartilages
- In direct contact with the thoracic wall without lung in between
- Attached to the body of sternum by pericardio-sternal ligaments

Contents of Fibrous Pericardium

Serous pericardium and its sinuses
Heart and its blood supply
Great vessels of the heart:
- Ascending aorta
- Pulmonary trunk
- Lower 1/2 of SVC
- Termination of IVC
- Four pulmonary veins

Serous Pericardium

A closed serous sac formed of two layers:
- Visceral layer (epicardium of the heart)
- Parietal layer:
  - Lines the inner surface of the fibrous pericardium
  - Reflected around the roots of the great vessels to become continuous with the visceral layer

Borders of the Heart

Right border: formed by the right atrium, convex to the right
Left border: formed by the left ventricle and the left auricle
Lower border: formed by the right ventricle (mainly) and the left ventricle

Surface Anatomy of the Heart

Surface anatomy of the sterno-costal surface of the heart is represented by points:
- Point B: at Lt. 2nd c.c. (1 cm) from the sternum
- Point A: at Rt. 3rd c.c. (1 cm) from the sternum
- Point D: at Rt. 6th c.c. (1 cm) from the sternum
- Point C (apex): at Lt. 5th intercostal space, (9 cm) to the left from the median plane
Coronary groove: oblique line from Lt. 3rd to Rt. 6th sternocostal junctions

Pericardium Definition and Structure

Definition: a fibro-serous sac that surrounds the heart and the proximal parts of the great vessels
Structure:
- Outer fibrous pericardium layer
- Inner serous pericardium layer
Extension: from 2 to 6 costal cartilages
Shape: conical, having base, apex, and four surfaces (anterior, posterior, and two laterals)

Relations and Fixation of Pericardium

Base: directed downwards, firmly attached to the central tendon of the diaphragm
Apex: directed upwards, and fused with the outer coats of the great vessels
Posterior surface: related to the posterior mediastinum and its contents, fused with the adventitia of the descending thoracic aorta

Pericardial Cavity

Found between the visceral and parietal layers
Contains a thin film of fluid
Function of serous pericardium: responsible for lubrication of the heart, preventing friction during its movement

Pericardiocentesis

Surgical puncture of the pericardial cavity for the aspiration of fluid
Necessary to relieve the pressure of accumulated fluid on the heart in case of pericardial effusion

Pericardial Sinuses

Transverse sinus:
- A transverse passage lined by the serous pericardium
- Situated between the ascending aorta and pulmonary trunk in front, and the superior vena cava, and pulmonary veins behind
- Clinical significance: allows surgeons to isolate the pulmonary trunk and ascending aorta during cardiac surgery
Oblique sinus:
- A recess of the serous pericardium, lies behind the left atrium of the heart
- Parietal layer of serous pericardium and fibrous pericardium separate the oblique sinus from the structures of the posterior mediastinum

Arterial Supply of Pericardium

Fibrous pericardium and parietal layer of the serous pericardium:
- Supplied by the pericardiacophrenic artery
- Supplied by pericardial branches of the descending thoracic aorta

Description

This quiz covers the anatomy of the heart, pericardium, and surrounding structures, including the lungs, pleura, and phrenic nerves. It also explores the functions of the fibrous pericardium and the relationships between these structures.