UAMS Department of Neurobiology and Developmental Sciences - Viscera of the Thorax

Gross Anatomy


Visceral Structures of the Thorax - Arranged Alphabetically

Organ/Part of Organ Location/Description Notes
apex tip of the left ventricle of the heart apex of the heart is located 3" to the left of the midline at the level of the 5th intercostal space
atrioventricular bundle part of the conduction system of the heart atrioventricular bundle is a strand of specialized myocardium that passes through the right fibrous trigone into the muscular part of the interventricular septum; it divides into right and left branches to supply the ventricles; also known as: bundle of His
atrioventricular node part of the conduction system of the heart atrioventricular node is located in the wall of the right atrium above the opening of the coronary sinus and the septal cusp of the tricuspid valve
atrioventricular valve, left heart valve located between the left atrium and the left ventricle left atrioventricular valve has two valve cusps; also known as: mitral or bicuspid valve
atrioventricular valve, right atrioventricular node between the right atrium and the right ventricle right atrioventricular valve has three valve cusps; also known as: tricuspid valve
atrium, right chamber of the heart that receives deoxygenated blood from the systemic circulation (body) right atrium forms the right margin of the heart; it receives blood from the superior vena cava, inferior vena cava and coronary sinus
atrium, left chamber of the heart that receives oxygenated blood from the pulmonic circulation (lungs) left atrium is located on the posterior aspect of the heart; it receives blood from the pulmonary vv.
auricle small appendage that projects anteriorly from the atrium paired, one on each atrium; right auricle lies beside the aorta and covers the right coronary artery; left auricle lies beside the pulmonary trunk
base the superior aspect of heart base of the heart is where the aorta, pulmonary trunk and superior vena cava exit/enter the heart
bronchi the air conducting passages of the lungs bronchi may be classified as primary, secondary (lobar), and tertiary (segmental)
bronchus, primary first branch of the air conducting system arising from the bifurcation of the trachea at T4/T5 intervertebral disc paired, right and left; one primary bronchus enters the hilus of each lung; the right primary bronchus is shorter, larger in diameter and more vertically oriented than the left so that aspirated foreign bodies tend to lodge in the right primary bronchus
bronchus, secondary a branch of the air conducting system arising from the primary bronchus there are 3 secondary bronchi in the right lung: upper, middle, lower; there are 2 secondary bronchi in the left lung: upper, lower; also known as: lobar bronchi
bronchus, tertiary a branch of the air conducting system arising from the secondary (lobar) bronchus there are 10 tertiary bronchi in the right lung: branching from the right superior lobar bronchus - apical, anterior, posterior; branching from the right middle lobar bronchus - medial, lateral; branching from the right inferior lobar bronchus - superior, anterior basal, posterior basal, medial basal, lateral basal; there are 8 tertiary bronchi in the left lung: branching from the left superior lobar bronchus - apicoposterior, anterior; branching from the lingular bronchus (off of the superior lobar bronchus) - superior lingular, inferior lingular; branching from the inferior lobar bronchus - superior, anteromedial basal, posterior basal, lateral basal; also known as: segmental bronchi
bronchus, segmental a branch of the air conducting system arising from the secondary (lobar) bronchus there are 10 tertiary bronchi in the right lung: branching from the right superior lobar bronchus - apical, anterior, posterior; branching from the right middle lobar bronchus - medial, lateral; branching from the right inferior lobar bronchus - superior, anterior basal, posterior basal, medial basal, lateral basal; there are 8 tertiary bronchi in the left lung: branching from the left superior lobar bronchus - apicoposterior, anterior; branching from the lingular bronchus (off of the superior lobar bronchus) - superior lingular, inferior lingular; branching from the inferior lobar bronchus - superior, anteromedial basal, posterior basal, lateral basal; also known as: segmental bronchi
carina keel-shaped cartilage lying within the tracheal bifurcation carina trachealis is an important landmark during endoscopy of the bronchial tree
chordae tendineae thin connective tissue cords that attach the atrioventricular valve cusps to the papillary mm. chordae tendineae are found only in the ventricles, not in the atria
coronary sulcus groove on the surface of the heart that separates the atria from the ventricles coronary sulcus contains the coronary sinus, circumflex a., and right coronary a.
crista terminalis ridge of cardiac muscle separating the smooth sinus venarum posteriorly from the roughened wall of the primitive atrium anteriorly the sinuatrial node lies within the superior end of the crista terminalis
cupula serous membrane lining the pleural cavity which extends above the level of the 1st rib into the root of the neck cupular pleura is continuous inferiorly with the costal and mediastinal parietal pleurae; it is reinforced by a specialization of scalene fascia (called Sibson's fascia or suprapleural membrane); also known as: cervical parietal pleura or cervical dome of pleura
esophagus the portion of the gastrointestinal tract between the pharynx and the stomach connects: superiorly with laryngopharynx at lower border of cricoid cartilage; inferiorly it passes through diaphragm at the T10 vertebral level to reach the stomach; the upper 1/3 is skeletal muscle innervated by the recurrent laryngeal, the lower 2/3rds is smooth muscle innervated by the vagus nn. via the esophageal plexus
fissure, oblique deep groove in the surface of the lung that separates the upper lobe from the lower lobe (both lungs), and the middle lobe from the lower lobe (right lung) oblique fissure extends from the level of the T3 vertebra posteriorly to the 6th costochondral junction anteriorly
fissure, horizontal deep groove in the surface of the lung that separates the middle lobe from the upper lobe (right lung only) horizontal fissure extends from the 5th rib at the mid-axillary line along the 4th rib to the sternum anteriorly
fossa ovalis shallow depression in the left wall of the right atrium fossa ovalis is the remnant of the foramen ovale which provided an open communication between the right atrium and left atrium in the fetus
heart muscular pump for blood located within middle mediastinum of the thorax heart is nearly surrounded by the pericardial sac and pericardial cavity
interventricular sulcus, anterior groove between the ventricles on the anterior surface of the heart anterior interventricular sulcus contains the anterior interventricular a. and the great cardiac v.; it marks the location of the interventricular septum
interventricular sulcus, posterior groove between the ventricles on the diaphragmatic surface of the heart posterior interventricular sulcus contains the posterior interventricular a. and the middle cardiac v.; it marks the location of the interventricular septum
ligamentum arteriosum fibrous cord of connective tissue that connects the left pulmonary a. near its origin with the undersurface of the aortic arch ligamentum arteriosum is a remnant of the ductus arteriosus; the left recurrent laryngeal n. passes beneath it
limbus fossa ovalis the ridge around the fossa ovalis in the left wall of the right atrium limbus fossa ovalis is the margin of the septum secundum
lobe, inferior the portion of the lung supplied by the inferior lobar bronchus inferior lobe of the right lung: possesses 5 bronchopulmonary segments - superior, anterior basal, posterior basal, medial basal, lateral basal; inferior lobe of the left lung: possesses 4 bronchopulmonary segments - superior, anteromedial basal, posterior basal, lateral basal
lobe, middle the portion of the right lung supplied by the middle lobar bronchus middle lobe is found in the right lung only; it possesses 2 bronchopulmonary segments: medial and lateral; lingula of the inferior lobe of the left lung is equivalent to the middle lobe of the right lung
lobe, superior the portion of the lung supplied by the superior lobar bronchus superior lobe of the right lung: possesses three bronchopulmonary segments - apical, anterior and posterior; superior lobe of the left lung: possesses four bronchopulmonary segments - apicoposterior, anterior, superior lingular, inferior lingular
lung the portion of the respiratory system where exchange of gasses occurs between the air and the blood; located in the thoracic cavity paired; right lung is divided into three lobes: superior, middle and inferior; left lung has two lobes: superior and inferior
mitral valve heart valve located between the left atrium and the left ventricle mitral valve has two valve cusps; it is named for the similarity of its shape to that of a bishop's miter; also known as: left atrioventricular valve or bicuspid valve
moderator band ridge of cardiac muscle spanning from the interventricular septum to the anterior papillary m. in the right ventricle septomarginal trabecula contains part of the right branch of the atrioventricular bundle; also known as: septomarginal trabecula
papillary muscle a small, nipple-like projection of cardiac muscle located within the ventricles papillary muscles attach to the cusps of the atrioventricular valves via chordae tendineae and act to keep the valve cusps from prolapsing under systolic blood pressure; there are three in the right atrium: anterior, posterior, septal; there are two in the left atrium: anterior, posterior
pectinate muscles prominent ridges of myocardium located on the inner surface of the right atrium pectinate muscles are very pronounced in the right atrium and in both auricles
pericardial sinus, oblique an area of the pericardial cavity located behind the left atrium of heart serous pericardium reflects onto the inferior vena cava and pulmonary vv. to define this space
pericardial sinus, transverse an area of the pericardial cavity located behind the aorta and pulmonary trunk and anterior to the superior vena cava transverse pericardial sinus was a simple structure when the heart tube began to form during development; it separates the outflow vessels from the inflow vessels of the heart
pericardium, fibrous a fibrous sac that attaches to the central tendon of the diaphragm and fuses with the adventitia of the great vessels superiorly fibrous pericardium contains the pericardial cavity and heart; it is lined on its inner surface by the parietal layer of serous pericardium; it defines the outermost boundary of the middle mediastinum
pericardium, parietal serous serous membrane lining the pericardial cavity; it is located on the inner surface of the fibrous pericardium parietal serous pericardium reflects onto the heart at the origins of the great vessels to become continuous with the visceral serous pericardium
pericardium, visceral serous serous membrane covering the surface of the heart visceral serous pericardium reflects onto the inner surface of the fibrous pericardium at the origins of the great vessels to become continuous with the parietal serous pericardium; also known as: epicardium
pleura serous membrane lining the pleural cavity there are two types of pleura: visceral pleura covers the lungs, parietal pleura lines the inner surfaces of the walls of pleural cavity; parietal pleura is sensitive to pain but visceral pleura is not sensitive to pain
pleura, cervical parietal serous membrane lining the pleural cavity which extends above the level of the 1st rib into the root of the neck cervical parietal pleura is continuous inferiorly with the costal and mediastinal parietal pleurae; it is reinforced by a specialization of scalene fascia (called Sibson's fascia or suprapleural membrane); also known as: cupula or cervical dome of pleura
pleura, costal parietal serous membrane lining the pleural cavity on the inner surfaces of the ribs, costal cartilages, and intercostal mm. costal parietal pleura is continuous anteriorly with the mediastinal parietal pleura at the costomediastinal reflection; it is continuous posteriorly with the mediastinal parietal pleural at the vertebral bodies; it is continuous inferiorly with the diaphragmatic parietal pleura at the costodiaphragmatic reflection; it is continuous superiorly with the cervical parietal pleura at the level of the 1st rib
pleura, diaphragmatic parietal serous membrane lining the pleural cavity on the superior surface of the diaphragm diaphragmatic parietal pleura is continuous superiorly with the costal parietal pleura at the costodiaphragmatic reflection; it is continuous superiorly with the mediastinal pleura at the inferomedial borders of the pleural cavities
pleura, mediastinal parietal serous membrane lining the pleural cavity on the lateral surface of the mediastinum mediastinal parietal pleura is continuous anteriorly with the costal parietal pleura at the costomediastinal reflection; it is continuous inferiorly with the diaphragmatic pleura at the inferomedial borders of the pleural cavities; it is continuous posteriorly with the costal parietal pleura lateral to the vertebral bodies; it is continuous superiorly with the cervical pleura at the level of the 1st rib
pleura, visceral serous membrane lining the surfaces of the lungs visceral pleura extends into the oblique and horizontal fissures of the lungs; it does not have pain fibers
pulmonary conus smooth area of the right ventricle below the opening into the pulmonary trunk pulmonary conus is the pulmonary part of the conus cordis which divides during development to form the outflow portions of the right and left ventricles
pulmonary ligament fold of pleura located below the root of the lung pulmonary ligament is where the visceral pleura and the mediastinal parietal pleura are continuous with each other
semilunar valves valve with three pocket-shaped cusps located in the base of the pulmonary trunk and ascending aorta semilunar valve has a thin endothelial free margin on each cusp called a lunula; a dense nodule is located at the midpoint of the free margin of each valve cusp; the pulmonary semilunar valve has anterior, left and right cusps; the aortic semilunar valve has right, left and posterior cusps
septomarginal trabecula ridge of cardiac muscle spanning from the interventricular septum to the anterior papillary m. in the right ventricle septomarginal trabecula contains part of the right branch of the atrioventricular bundle; also known as: moderator band
sinuatrial node part of the conduction system of the heart sinuatrial node is located within the crista terminalis near the superior vena cava; it is the "pacemaker" of the heart
sulcus terminalis groove on the external surface of the right atrium marking the location of the crista terminalis the sinuatrial node is located at the superior end of the crista terminalis
trabeculae carnae ridges of cardiac muscle located on the inner wall of both ventricles the word trabecula is derived from the Latin word trabs, which means a beam
trachea main airway that lies anterior to the esophagus trachea extends from vertebral level C6 to the level of the T4/5 intervertebral disc; superiorly it is connected to the cricoid cartilage via the cricotracheal ligament; it bifurcates into two primary bronchi
tricuspid valve a three cusped valve located at the ostium between the right atrium and the right ventricle tricuspid valve possesses anterior, posterior and septal cusps; also known as: right atrioventricular valve
ventricle, right heart chamber that pumps blood to the pulmonary circulation right ventricle has a septomarginal trabecula and 3 papillary mm.; it pumps blood into the pulmonary trunk
ventricle, left heart chamber that pumps blood to the systemic circulation left ventricle has 2 papillary mm.; it pumps blood into the ascending aorta


Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

The content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2009, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.
Unauthorized use is prohibited.




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